1.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
2.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
3.
Mollusca
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The molluscs compose the large phylum Mollusca of invertebrate animals. Around 85,000 extant species of molluscs are recognized, molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats and they are highly diverse, not just in size and in anatomical structure, but also in behaviour and in habitat. The phylum is divided into 9 or 10 taxonomic classes. The gastropods are by far the most numerous molluscs in terms of classified species, the three most universal features defining modern molluscs are a mantle with a significant cavity used for breathing and excretion, the presence of a radula, and the structure of the nervous system. Other than these things, molluscs express great morphological diversity, so many textbooks base their descriptions on an ancestral mollusc. This has a single, limpet-like shell on top, which is made of proteins and chitin reinforced with calcium carbonate, the underside of the animal consists of a single muscular foot. Although molluscs are coelomates, the coelom tends to be small, the main body cavity is a hemocoel through which blood circulates, their circulatory systems are mainly open. The generalized mollusc has two paired nerve cords, or three in bivalves, the brain, in species that have one, encircles the esophagus. Most molluscs have eyes, and all have sensors to detect chemicals, vibrations, the simplest type of molluscan reproductive system relies on external fertilization, but more complex variations occur. All produce eggs, from which may emerge trochophore larvae, more complex veliger larvae, good evidence exists for the appearance of gastropods, cephalopods and bivalves in the Cambrian period 541 to 485.4 million years ago. Molluscs have, for centuries, also been the source of important luxury goods, notably pearls, mother of pearl, Tyrian purple dye and their shells have also been used as money in some preindustrial societies. Mollusc species can also represent hazards or pests for human activities, the bite of the blue-ringed octopus is often fatal, and that of Octopus apollyon causes inflammation that can last for over a month. Stings from a few species of large tropical cone shells can also kill, schistosomiasis is transmitted to humans via water snail hosts, and affects about 200 million people. Snails and slugs can also be serious pests, and accidental or deliberate introduction of some snail species into new environments has seriously damaged some ecosystems. The words mollusc and mollusk are both derived from the French mollusque, which originated from the Latin molluscus, from mollis, molluscus was itself an adaptation of Aristotles τα μαλακά, the soft things, which he applied to cuttlefish. The scientific study of molluscs is accordingly called malacology, as it is now known these groups have no relation to molluscs, and very little to one another, the name Molluscoida has been abandoned. The most universal features of the structure of molluscs are a mantle with a significant cavity used for breathing and excretion
4.
Cephalopod
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A cephalopod is any member of the molluscan class Cephalopoda. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, fishermen sometimes call them inkfish, referring to their common ability to squirt ink. The study of cephalopods is a branch of known as teuthology. Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids, the class now contains two, only distantly related, extant subclasses, Coleoidea, which includes octopuses, squid, and cuttlefish, and Nautiloidea, represented by Nautilus and Allonautilus. In the Coleoidea, the shell has been internalized or is absent, whereas in the Nautiloidea. About 800 living species of cephalopods have been identified, two important extinct taxa are the Ammonoidea and Belemnoidea. There are over 800 extant species of cephalopod, although new species continue to be described, an estimated 11,000 extinct taxa have been described, although the soft-bodied nature of cephalopods means they are not easily fossilised. Cephalopods are found in all the oceans of Earth, none of them can tolerate freshwater, but the brief squid, Lolliguncula brevis, found in Chesapeake Bay, is a notable partial exception in that it tolerates brackish water. Cephalopods are thought to be unable to live in due to multiple biochemical constraints. Cephalopods occupy most of the depth of the ocean, from the plain to the sea surface. Their diversity is greatest near the equator and decreases towards the poles, Cephalopods are widely regarded as the most intelligent of the invertebrates, and have well developed senses and large brains. The nervous system of cephalopods is the most complex of the invertebrates, the brain is protected in a cartilaginous cranium. Cephalopods have also known to climb out of their aquaria, maneuver a distance of the lab floor, enter another aquarium to feed on the crabs. Cephalopods are social creatures, when isolated from their own kind, some cephalopods are able to fly through the air for distances of up to 50 m. While cephalopods are not particularly aerodynamic, they achieve these impressive ranges by jet-propulsion, the animals spread their fins and tentacles to form wings and actively control lift force with body posture. Cephalopods have advanced vision, can detect gravity with statocysts, and have a variety of sense organs. Octopuses use their arms to explore their environment and can use them for depth perception, most cephalopods rely on vision to detect predators and prey, and to communicate with one another. Consequently, cephalopod vision is acute, training experiments have shown that the octopus can distinguish the brightness, size, shape
5.
Octopus
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The octopus is a cephalopod mollusc of the order Octopoda. It has two eyes and four pairs of arms and, like other cephalopods, it is bilaterally symmetric and it has a beak, with its mouth at the center point of the arms. It has no internal or external skeleton, allowing it to squeeze through tight places, octopuses are among the most intelligent and behaviorally diverse of all invertebrates. Octopuses inhabit diverse regions of the ocean, including reefs, pelagic waters. They trail their eight arms behind them as they swim, all octopuses are venomous, but only one group, the blue-ringed octopuses, is known to be deadly to humans. Around 300 species are recognized, which is over one-third of the number of known cephalopod species. The term octopus may also be used to specifically to the genus Octopus. Octopuses appear in mythology as sea monsters like the Kraken of Norway and the Akkorokamui of the Ainu, a battle with an octopus appears in Victor Hugos book Toilers of the Sea, inspiring other works such as Ian Flemings Octopussy. Octopuses appear in Japanese erotic art, shunga and they are eaten in many parts of the world, especially the Mediterranean and the Asian seas. The scientific Latin term octopus was derived from Ancient Greek ὀκτώπους, related to the word octopus are the terms Octopoda and the adjectival octopoid. The standard pluralized form of octopus in the English language is octopuses /ˈɒktəpʊsɪz/, the alternative plural octopi – which misguidedly assumes it is a Latin -us-word – is considered grammatically incorrect. It is nevertheless used frequently enough to make it notable, and was acknowledged by the descriptivist Merriam-Webster 11th Collegiate Dictionary. The Oxford English Dictionary lists octopuses, octopi, and octopodes, in order, labeling octopodes as rare. The underside of the arms are covered in circular, adhesive suckers, while often called tentacles, the arms of octopuses are often distinguished from the pair of feeding tentacles found in squid and cuttlefish. The bulbous and hollow mantle is fused to the back of the head, Most of the vital organs are contained in the mantle while the central brain is located in the head. The eyes of the octopus are located at the top of the head, anatomical and embryological evidence shows that the tentacles are part of the ventral side, while the abdomen is dorsal, the head forms forms the anterior and the mantle posterior. The mouth of an octopus, located underneath the tentacles, contains a hard beak on the outside and a radula. Both of these structures are made of chitin, Most of the octopus body is made of soft material allowing it to lengthen, contract, and contort itself
6.
Octopus (genus)
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Octopus is the largest genus of octopuses, comprising more than 100 species. These species are widespread throughout the worlds oceans, many species formerly placed in the genus Octopus are now assigned to other genera within the family Octopodidae. The word heritages from the number eight, octo and pous. The species listed above with an asterisk are questionable and need further study to determine if they are valid species or synonyms, species brought into synonymy CephBase, Octopus Tree of Life website gives information about the classification of cephalopod groups
7.
Binomial nomenclature
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Such a name is called a binomial name, a binomen, binominal name or a scientific name, more informally it is also called a Latin name. The first part of the name identifies the genus to which the species belongs, for example, humans belong to the genus Homo and within this genus to the species Homo sapiens. The formal introduction of system of naming species is credited to Carl Linnaeus. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus. Although the general principles underlying binomial nomenclature are common to these two codes, there are differences, both in the terminology they use and in their precise rules. Similarly, both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a name is usually given, at least when it is first mentioned. In zoology Patella vulgata Linnaeus,1758, the original name given by Linnaeus was Fringilla domestica, the parentheses indicate that the species is now considered to belong in a different genus. The ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, in botany Amaranthus retroflexus L. – L. is the standard abbreviation used in botany for Linnaeus. – Linnaeus first named this bluebell species Scilla italica, Rothmaler transferred it to the genus Hyacinthoides, the ICN does not require that the dates of either publication be specified. Prior to the adoption of the binomial system of naming species. Together they formed a system of polynomial nomenclature and these names had two separate functions. First, to designate or label the species, and second, to be a diagnosis or description, such polynomial names may sometimes look like binomials, but are significantly different. For example, Gerards herbal describes various kinds of spiderwort, The first is called Phalangium ramosum, Branched Spiderwort, is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia. The Latin phrases are short descriptions, rather than identifying labels, the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné. It was in his 1753 Species Plantarum that he first began using a one-word trivial name together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as an epithet or specific name
8.
Georges Cuvier
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Jean Léopold Nicolas Frédéric Cuvier, known as Georges Cuvier, was a French naturalist and zoologist, sometimes referred to as the father of paleontology. Cuvier is also known for establishing extinction as a fact—at the time, in his Essay on the Theory of the Earth Cuvier was interpreted to have proposed that new species were created after periodic catastrophic floods. In this way, Cuvier became the most influential proponent of catastrophism in geology in the early 19th century and his study of the strata of the Paris basin with Alexandre Brongniart established the basic principles of biostratigraphy. Cuvier is also remembered for strongly opposing theories of evolution, which at the time were mainly proposed by Jean-Baptiste de Lamarck, Cuvier believed there was no evidence for evolution, but rather evidence for cyclical creations and destructions of life forms by global extinction events such as deluges. Cuvier supported function and rejected Lamarcks thinking and his most famous work is Le Règne Animal. In 1819, he was created a peer for life in honor of his scientific contributions, thereafter, he was known as Baron Cuvier. He died in Paris during an epidemic of cholera, some of Cuviers most influential followers were Louis Agassiz on the continent and in the United States, and Richard Owen in Britain. His name is one of the 72 names inscribed on the Eiffel Tower, Cuvier was born in Montbéliard, France, where his Protestant ancestors had lived since the time of the Reformation. His father, Jean George Cuvier, was a lieutenant in the Swiss Guards, at the time, the town, which was annexed to France on 10 October 1793, belonged to the Duchy of Württemberg. His mother, who was younger than his father, tutored him diligently throughout his early years. During his gymnasium years, he had trouble acquiring Latin and Greek, and was always at the head of his class in mathematics, history. At the age of 10, soon entering the gymnasium, he encountered a copy of Conrad Gessners Historiae Animalium. He then began frequent visits to the home of a relation, all of these he read and reread, retaining so much of the information, that by the age of 12, he was as familiar with quadrupeds and birds as a first-rate naturalist. He remained at the gymnasium for four years, Cuvier spent an additional four years at the Caroline Academy in Stuttgart, where he excelled in all of his coursework. Although he knew no German on his arrival, after nine months of study. Upon graduation, he had no money on which to live as he awaited appointment to an academic office, so in July 1788, he took a job at Fiquainville chateau in Normandy as tutor to the only son of the Comte dHéricy, a Protestant noble. There, during the early 1790s, he began his comparisons of fossils with extant forms, Cuvier regularly attended meetings held at the nearby town of Valmont for the discussion of agricultural topics. There, he acquainted with Henri Alexandre Tessier, who had assumed a false identity
9.
Synonym (taxonomy)
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For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies. This name is no longer in use, it is now a synonym of the current scientific name which is Picea abies, unlike synonyms in other contexts, in taxonomy a synonym is not interchangeable with the name of which it is a synonym. In taxonomy, synonyms are not equals, but have a different status, for any taxon with a particular circumscription, position, and rank, only one scientific name is considered to be the correct one at any given time. A synonym cannot exist in isolation, it is always an alternative to a different scientific name, given that the correct name of a taxon depends on the taxonomic viewpoint used a name that is one taxonomists synonym may be another taxonomists correct name. Synonyms may arise whenever the same taxon is described and named more than once, independently. They may also arise when existing taxa are changed, as when two taxa are joined to one, a species is moved to a different genus. To the general user of scientific names, in such as agriculture, horticulture, ecology, general science. A synonym is a name that was used as the correct scientific name but which has been displaced by another scientific name. Thus Oxford Dictionaries Online defines the term as a name which has the same application as another. In handbooks and general texts, it is useful to have mentioned as such after the current scientific name. Synonyms used in this way may not always meet the strict definitions of the synonym in the formal rules of nomenclature which govern scientific names. Changes of scientific name have two causes, they may be taxonomic or nomenclatural, a name change may be caused by changes in the circumscription, position or rank of a taxon, representing a change in taxonomic, scientific insight. A name change may be due to purely nomenclatural reasons, that is, based on the rules of nomenclature, the earliest such name is called the senior synonym, while the later name is the junior synonym. One basic principle of zoological nomenclature is that the earliest correctly published name, synonyms are important because if the earliest name cannot be used, then the next available junior synonym must be used for the taxon. Objective synonyms refer to taxa with the type and same rank. For example, John Edward Gray published the name Antilocapra anteflexa in 1855 for a species of pronghorn, however, it is now commonly accepted that his specimen was an unusual individual of the species Antilocapra americana published by George Ord in 1815. Ords name thus takes precedence, with Antilocapra anteflexa being a subjective synonym. Objective synonyms are common at the level of genera, because for various reasons two genera may contain the type species, these are objective synonyms
10.
Mediterranean Sea
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The sea is sometimes considered a part of the Atlantic Ocean, although it is usually identified as a separate body of water. The name Mediterranean is derived from the Latin mediterraneus, meaning inland or in the middle of land and it covers an approximate area of 2.5 million km2, but its connection to the Atlantic is only 14 km wide. The Strait of Gibraltar is a strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Gibraltar. In oceanography, it is called the Eurafrican Mediterranean Sea or the European Mediterranean Sea to distinguish it from mediterranean seas elsewhere. The Mediterranean Sea has a depth of 1,500 m. The sea is bordered on the north by Europe, the east by Asia and it is located between latitudes 30° and 46° N and longitudes 6° W and 36° E. Its west-east length, from the Strait of Gibraltar to the Gulf of Iskenderun, the seas average north-south length, from Croatia’s southern shore to Libya, is approximately 800 km. The Mediterranean Sea, including the Sea of Marmara, has an area of approximately 2,510,000 square km. The sea was an important route for merchants and travelers of ancient times that allowed for trade, the history of the Mediterranean region is crucial to understanding the origins and development of many modern societies. In addition, the Gaza Strip and the British Overseas Territories of Gibraltar and Akrotiri, the term Mediterranean derives from the Latin word mediterraneus, meaning amid the earth or between land, as it is between the continents of Africa, Asia and Europe. The Ancient Greek name Mesogeios, is similarly from μέσο, between + γη, land, earth) and it can be compared with the Ancient Greek name Mesopotamia, meaning between rivers. The Mediterranean Sea has historically had several names, for example, the Carthaginians called it the Syrian Sea and latter Romans commonly called it Mare Nostrum, and occasionally Mare Internum. Another name was the Sea of the Philistines, from the people inhabiting a large portion of its shores near the Israelites, the sea is also called the Great Sea in the General Prologue by Geoffrey Chaucer. In Ottoman Turkish, it has also been called Bahr-i Sefid, in Modern Hebrew, it has been called HaYam HaTikhon, the Middle Sea, reflecting the Seas name in ancient Greek, Latin, and modern languages in both Europe and the Middle East. Similarly, in Modern Arabic, it is known as al-Baḥr al-Mutawassiṭ, in Turkish, it is known as Akdeniz, the White Sea since among Turks the white colour represents the west. Several ancient civilisations were located around the Mediterranean shores, and were influenced by their proximity to the sea. It provided routes for trade, colonisation, and war, as well as food for numerous communities throughout the ages, due to the shared climate, geology, and access to the sea, cultures centered on the Mediterranean tended to have some extent of intertwined culture and history. Two of the most notable Mediterranean civilisations in classical antiquity were the Greek city states, later, when Augustus founded the Roman Empire, the Romans referred to the Mediterranean as Mare Nostrum
11.
England
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England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west, the Irish Sea lies northwest of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east, the country covers five-eighths of the island of Great Britain in its centre and south, and includes over 100 smaller islands such as the Isles of Scilly, and the Isle of Wight. England became a state in the 10th century, and since the Age of Discovery. The Industrial Revolution began in 18th-century England, transforming its society into the worlds first industrialised nation, Englands terrain mostly comprises low hills and plains, especially in central and southern England. However, there are uplands in the north and in the southwest, the capital is London, which is the largest metropolitan area in both the United Kingdom and the European Union. In 1801, Great Britain was united with the Kingdom of Ireland through another Act of Union to become the United Kingdom of Great Britain and Ireland. In 1922 the Irish Free State seceded from the United Kingdom, leading to the latter being renamed the United Kingdom of Great Britain, the name England is derived from the Old English name Englaland, which means land of the Angles. The Angles were one of the Germanic tribes that settled in Great Britain during the Early Middle Ages, the Angles came from the Angeln peninsula in the Bay of Kiel area of the Baltic Sea. The earliest recorded use of the term, as Engla londe, is in the ninth century translation into Old English of Bedes Ecclesiastical History of the English People. According to the Oxford English Dictionary, its spelling was first used in 1538. The earliest attested reference to the Angles occurs in the 1st-century work by Tacitus, Germania, the etymology of the tribal name itself is disputed by scholars, it has been suggested that it derives from the shape of the Angeln peninsula, an angular shape. An alternative name for England is Albion, the name Albion originally referred to the entire island of Great Britain. The nominally earliest record of the name appears in the Aristotelian Corpus, specifically the 4th century BC De Mundo, in it are two very large islands called Britannia, these are Albion and Ierne. But modern scholarly consensus ascribes De Mundo not to Aristotle but to Pseudo-Aristotle, the word Albion or insula Albionum has two possible origins. Albion is now applied to England in a poetic capacity. Another romantic name for England is Loegria, related to the Welsh word for England, Lloegr, the earliest known evidence of human presence in the area now known as England was that of Homo antecessor, dating to approximately 780,000 years ago. The oldest proto-human bones discovered in England date from 500,000 years ago, Modern humans are known to have inhabited the area during the Upper Paleolithic period, though permanent settlements were only established within the last 6,000 years
12.
Senegal
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Senegal, officially the Republic of Senegal, is a country in West Africa. Senegal is bordered by Mauritania in the north, Mali to the east, Guinea to the southeast, and Guinea-Bissau to the southwest. Senegal also borders The Gambia, a country occupying a narrow sliver of land along the banks of the Gambia River, Senegal also shares a maritime border with Cape Verde. Senegals economic and political capital is Dakar and it is the westernmost country in the mainland of the Old World, or Afro-Eurasia, and owes its name to the Senegal River, which borders it to the east and north. The name Senegal comes from the Wolof Sunuu Gaal, which means Our Boat, Senegal covers a land area of almost 197,000 square kilometres and has an estimated population of about 15 million. The climate is Sahelian, but there is a rainy season, the territory of modern Senegal has been inhabited by various ethnic groups since prehistory. Organized kingdoms emerged around the century, and parts of the country were ruled by prominent regional empires such as the Jolof Empire. The present state of Senegal has its roots in European colonialism, which began during the mid-15th century, the establishment of coastal trading posts gradually led to control of the mainland, culminating in French rule of the area by the 19th century, albeit amid much local resistance. Senegal peacefully attained independence from France in 1960, and has since been among the politically stable countries in Africa. Senegals economy is centered mostly on commodities and natural resources, major industries are fish processing, phosphate mining, fertilizer production, petroleum refining, construction materials, and ship construction and repair. As in most African nations, agriculture is a sector, with Senegal producing several important cash crops, including peanuts, sugarcane, cotton, green beans, tomatoes, melons. Owing to its stability, tourism and hospitality are also burgeoning sectors. A multiethnic and secular nation, Senegal is predominantly Sunni Muslim with Sufi, French is the official language, although many native languages are spoken and recognized. Since April 2012 Senegals president has been Macky Sall, Senegal has been a member of the Organisation internationale de la Francophonie since 1970. Senegal is named after the Senegal River, the etymology of which is contested, one popular theory is that it stems from the Wolof phrase sunu gaal, which means our canoe, resulting from a miscommunication between 15th-century Portuguese sailors and Wolof fishermen. The our canoe theory has been embraced in modern Senegal for its charm. It is frequently used in appeals to national solidarity, frequently heard in the media, modern historians believe the name probably refers to the Sanhaja, Berbers who lived on the northern side of the river. A competing theory is that it derives from the town of Sanghana
13.
Africa
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Africa is the worlds second-largest and second-most-populous continent. At about 30.3 million km² including adjacent islands, it covers 6% of Earths total surface area and 20.4 % of its land area. With 1.2 billion people as of 2016, it accounts for about 16% of the human population. The continent includes Madagascar and various archipelagos and it contains 54 fully recognized sovereign states, nine territories and two de facto independent states with limited or no recognition. Africas population is the youngest amongst all the continents, the age in 2012 was 19.7. Algeria is Africas largest country by area, and Nigeria by population, afarensis, Homo erectus, H. habilis and H. ergaster – with the earliest Homo sapiens found in Ethiopia being dated to circa 200,000 years ago. Africa straddles the equator and encompasses numerous climate areas, it is the continent to stretch from the northern temperate to southern temperate zones. Africa hosts a diversity of ethnicities, cultures and languages. In the late 19th century European countries colonized most of Africa, Africa also varies greatly with regard to environments, economics, historical ties and government systems. However, most present states in Africa originate from a process of decolonization in the 20th century, afri was a Latin name used to refer to the inhabitants of Africa, which in its widest sense referred to all lands south of the Mediterranean. This name seems to have referred to a native Libyan tribe. The name is connected with Hebrew or Phoenician ʿafar dust. The same word may be found in the name of the Banu Ifran from Algeria and Tripolitania, under Roman rule, Carthage became the capital of the province of Africa Proconsularis, which also included the coastal part of modern Libya. The Latin suffix -ica can sometimes be used to denote a land, the later Muslim kingdom of Ifriqiya, modern-day Tunisia, also preserved a form of the name. According to the Romans, Africa lay to the west of Egypt, while Asia was used to refer to Anatolia, as Europeans came to understand the real extent of the continent, the idea of Africa expanded with their knowledge. 25,4, whose descendants, he claimed, had invaded Libya, isidore of Seville in Etymologiae XIV.5.2. Suggests Africa comes from the Latin aprica, meaning sunny, massey, in 1881, stated that Africa is derived from the Egyptian af-rui-ka, meaning to turn toward the opening of the Ka. The Ka is the double of every person and the opening of the Ka refers to a womb or birthplace
14.
Azores
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Its main industries are agriculture, dairy farming, livestock, fishing, and tourism, which is becoming the major service activity in the region. In addition, the government of the Azores employs a large percentage of the population directly or indirectly in the service, the main settlement of the Azores is Ponta Delgada. There are nine major Azorean islands and a cluster, in three main groups. These are Flores and Corvo, to the west, Graciosa, Terceira, São Jorge, Pico, and Faial in the centre, and São Miguel, Santa Maria, and they extend for more than 600 km and lie in a northwest-southeast direction. All the islands have volcanic origins, although some, such as Santa Maria, have had no recorded activity since the islands were settled, mount Pico, on the island of Pico, is the highest point in Portugal, at 2,351 m. The Azores are actually some of the tallest mountains on the planet, measured from their base at the bottom of the ocean to their peaks, which thrust high above the surface of the Atlantic. The climate of the Azores is very mild for such a location, being influenced by its distance to continents. Due to the influence, temperatures remain mild year-round. Daytime temperatures normally fluctuate between 16 °C and 25 °C depending on season, temperatures above 30 °C or below 3 °C are unknown in the major population centres. It is also generally wet and cloudy, the culture, dialect, cuisine, and traditions of the Azorean islands vary considerably, because these once-uninhabited and remote islands were settled sporadically over a span of two centuries. However, these kinds of structures have always used in the Azores to store cereals. Detailed examination and dating to authenticate the validity of these speculations is lacking and it is unclear whether these structures are natural or man-made and whether they predate the 15th-century Portuguese colonization of the Azores. Solid confirmation of a human presence in the archipelago has not yet been published. The islands were known in the century and parts of them appear in the Atlas Catalan. In 1427, a captain sailing for Henry the Navigator, possibly Gonçalo Velho, rediscovered the Azores, but this is not certain. In Thomas Ashes 1813 work, A History of the Azores, the author identified a Fleming, Joshua Vander Berg of Bruges and he stated that the Portuguese explored the area and claimed it for Portugal. Other stories note the discovery of the first islands by sailors in the service of Henry the Navigator, although there are few documents to support the claims. Although it is said that the archipelago received its name from the goshawk
15.
Canary Islands
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The Canary Islands, also known as the Canaries, are an archipelago and autonomous community of Spain located on the Atlantic Ocean,100 kilometres west of Morocco. The Canaries are among the outermost regions of the European Union proper and it is also one of the eight regions with special consideration of historical nationality recognized as such by the Spanish Government. The main islands are Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, the archipelago also includes a number of islands and islets, La Graciosa, Alegranza, Isla de Lobos, Montaña Clara, Roque del Oeste and Roque del Este. In ancient times, the chain was often referred to as the Fortunate Isles. The Canary Islands is the most southerly region of Spain and the largest and most populated archipelago of the Macaronesia region, the islands have a subtropical climate, with long hot summers and moderately warm winters. The precipitation levels and the level of maritime moderation varies depending on location and elevation, green areas as well as desert exist on the archipelago. Due to their location above the inversion layer, the high mountains of these islands are ideal for astronomical observation. For this reason, two professional observatories, Teide Observatory on the island of Tenerife and Roque de los Muchachos Observatory on the island of La Palma, have built on the islands. Las Palmas de Gran Canaria has been the largest city in the Canaries since 1768, between the 1833 territorial division of Spain and 1927 Santa Cruz de Tenerife was the sole capital of the Canary Islands. In 1927 a decree ordered that the capital of the Canary Islands be shared, the third largest city of the Canary Islands is San Cristóbal de La Laguna on Tenerife. This city is home to the Consejo Consultivo de Canarias. During the time of the Spanish Empire, the Canaries were the main stopover for Spanish galleons on their way to the Americas, who came south to catch the prevailing northeasterly trade winds. The name Islas Canarias is likely derived from the Latin name Canariae Insulae, meaning Islands of the Dogs, according to the historian Pliny the Elder, the Mauretanian king Juba II named the island Canaria because it contained vast multitudes of dogs of very large size. Another speculation is that the dogs were actually a species of monk seal, critically endangered. The dense population of seals may have been the characteristic that most struck the few ancient Romans who established contact with these islands by sea. Alternatively, it is said that the inhabitants of the island, Guanches, used to worship dogs, mummified them. The ancient Greeks also knew about a people, living far to the west, who are the dog-headed ones, who worshipped dogs on an island. Some hypothesize that the Canary Islands dog-worship and the ancient Egyptian cult of the god, Anubis are closely connected
16.
Cape Verde
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Located 570 kilometres off the coast of West Africa, the islands cover a combined area of slightly over 4,000 square kilometres. The Cape Verde archipelago was uninhabited until the 15th century, when Portuguese explorers discovered and colonized the islands, ideally located for the Atlantic slave trade, the islands grew prosperous throughout the 16th and 17th centuries, attracting merchants, privateers, and pirates. The end of slavery in the 19th century led to economic decline, Cape Verde gradually recovered as an important commercial center and stopover for shipping routes. Incorporated as a department of Portugal in 1951, the islands continued to agitate for independence. Since the early 1990s, Cape Verde has been a representative democracy. Lacking natural resources, its economy is mostly service-oriented, with a growing focus on tourism. Its population of around 512,000 is mostly of mixed European and sub-Saharan African heritage, a sizeable diaspora community exists across the world, slightly outnumbering inhabitants on the islands. Historically, the name Cape Verde has been used in English for the archipelago and, since independence in 1975, for the country. In 2013, the Cape Verdean government determined that the Portuguese designation Cabo Verde would henceforth be used for official purposes, such as at the United Nations, Cape Verde is a member of the African Union. The name of the stems from the nearby Cap-Vert, on the Senegalese coast. In 1444 Portuguese explorers had named that landmark as Cabo Verde, on 24 October 2013, the countrys delegation announced at the United Nations that the official name should no longer be translated into other languages. Instead of Cape Verde, the designation Republic of Cabo Verde is to be used, before the arrival of Europeans, the Cape Verde Islands were uninhabited. The islands of the Cape Verde archipelago were discovered by Genoese and Portuguese navigators around 1456, according to Portuguese official records, the first discoveries were made by Genoa-born António de Noli, who was afterwards appointed governor of Cape Verde by Portuguese King Afonso V. Other navigators mentioned as contributing to discoveries in the Cape Verde archipelago are Diogo Gomes, Diogo Dias, Diogo Afonso, in 1462, Portuguese settlers arrived at Santiago and founded a settlement they called Ribeira Grande. Ribeira Grande was the first permanent European settlement in the tropics, in the 16th century, the archipelago prospered from the Atlantic slave trade. Pirates occasionally attacked the Portuguese settlements, sir Francis Drake, an English corsair privateering under a letter of marque granted by the English crown, twice sacked the capital Ribeira Grande in 1585 when it was a part of the Iberian Union. After a French attack in 1712, the town declined in relative to nearby Praia. Decline in the trade in the 19th century resulted in an economic crisis
17.
Mantle (mollusc)
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The mantle is a significant part of the anatomy of molluscs, it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself. In many species of molluscs the epidermis of the mantle secretes calcium carbonate and conchiolin, in sea slugs there is a progressive loss of the shell and the mantle becomes the dorsal surface of the animal. The words mantle and pallium both originally meant cloak or cape, see mantle, the mantle cavity is a central feature of molluscan biology. This cavity is formed by the skirt, a double fold of mantle which encloses a water space. This space contains the gills, anus, osphradium, nephridiopores. The mantle cavity functions as a chamber in most molluscs. In bivalves it is part of the feeding structure. In some molluscs the mantle cavity is a chamber, and in cephalopods and some bivalves such as scallops. In cephalopods the contraction of the mantle is used to water through a tubular siphon, the hyponome. In gastropods it is used as a kind of foot for locomotion over the surface, in Patella the foot includes the entire ventral surface of the animal. The foot of the Bivalvia is a fleshy process adapted by its form to digging rather than to locomotion, in shelled molluscs, the mantle is the organ that forms the shell, and adds to the shell to increase its size and strength as the animal grows. Shell material is secreted by the cells of the mantle tissue. The mantle of many gastropods is usually fully or partially hidden inside the gastropod shell, in species where the shell is small compared to the size of the body, more of the mantle shows. Shell-less slugs have the mantle fully visible, the dorsal surface of the mantle is called the notum, while the ventral surface of the mantle is called the hyponotum. In the family Philomycidae, the covers the whole back side of the body. Mollusc shell, which is formed by the mantle Siphon, which is a part of the mantle in some groups of molluscs
18.
Animals (Scientific Procedures) Act 1986
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The Animals Act 1986, sometimes referred to as ASPA, is an Act of the Parliament of the United Kingdom passed in 1986, which regulates the use of animals used for research in the UK. Revised legislation came into force on January 1st 2013, prior to ASPA, the use of animals in the UK was regulated by the Cruelty to Animals Act 1876, which enforced a licensing and inspection system for vivisection. Animal cruelty was previously regulated by the Protection of Animals Act 1911 and more recently by the Animal Welfare Act 2006, specific exemptions apply to experiments licensed under the 1986 Act. A1993 amendment added a single species, the common octopus. The Act applied only to protected animals from halfway through their gestation or incubation periods or from when they became capable of independent feeding, primates, cats, dogs and horses had additional protection over other vertebrates under the Act. Revised legislation came into force on January 1st 2013, other considerations in the Act include animal sources, housing conditions, identification methods and the humane killing of animals. This legislation is widely regarded as the strictest in the world protecting animals used in research and those applying for a license must explain why such research cannot be done through non-animal or in-vitro methods. The project must also pass an ethical review panel which aims to decide if the benefits outweigh any suffering for the animals involved. ASPA involves three levels of regulation — person, project, and place, the person level is achieved by the granting of a personal licence to a researcher wishing to carry out regulated procedures on a protected animal. Having undergone a defined sequence of training, a researcher can apply for a PIL permitting specified techniques to be carried out on named species of animals, the project level of regulation is governed by the granting of a project licence to a suitably qualified senior researcher. Typically a large and detailed document, the PPL precisely defines which techniques may be applied to particular animals and it is an offence under ASPA to carry out regulated procedures on a protected animal unless authorised by a personal licence, a project licence, and a certificate of designation. A report by Animal Aid called the Act a vivisectors charter, alleging that it allows researchers to do as they please, a 2002 House of Lords select committee inquiry compared the Act to legislation from France, the U. S. and Japan. Note that costs are explicitly in terms of effects on animals. In 2005, Patricia Hewitt, then British Secretary of State for Trade and Industry, Animal law Pain in animals Pain in invertebrates Animal welfare in the United Kingdom
19.
Cephalopod intelligence
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Cephalopod intelligence has an important comparative aspect in the understanding of intelligence because it relies on a nervous system fundamentally different from that of vertebrates. The cephalopod class of molluscs, particularly the Coleoidea subclass, are thought to be the most intelligent invertebrates, the scope of cephalopod intelligence is controversial, complicated by the challenges of studying these elusive and fundamentally different creatures. In spite of this, the existence of impressive spatial learning capacity, navigational abilities, unlike most other molluscs, all cephalopods are active predators. Their requirement to locate and capture their prey has been a driving force behind the development of their intelligence. The Humboldt squid hunts schools of fish, showing extraordinary cooperation and communication in its hunting techniques and this is the first observation of such behaviour in invertebrates. In the face of challenges, octopuses will instead seek out lobster traps. They are also known to climb aboard fishing boats and hide in the containers that hold dead or dying crabs, dexterity, an ability essential for tool use and manipulation, is also found in cephalopods. The highly sensitive suction cups and prehensile arms of octopuses, squid, at the Sea Star Aquarium in Coburg, Germany, an octopus named Otto was known to juggle his fellow tankmates around, as well as throw rocks and smash the aquarium glass. On more than one occasion, Otto even caused short circuits by crawling out of his tank, Octopus opening a container with a screw cap Another example of cephalopod intelligence is the communication that takes place between the more social species of squid. Some cephalopods are capable of changes in skin colour and pattern through nervous control of chromatophores. This ability almost certainly evolved primarily for camouflage, but squid use colour, patterns, caribbean reef squid can send one message using colour patterns to a squid on their right, while they send another message to a squid on their left. The octopus has repeatedly shown to exhibit flexibility in the use of tools. It is surmised that the originally used bivalves for the same purpose. Classical conditioning of cephalopods has been reported, one study concluded that octopuses are capable of using observational learning, however, this is disputed. Cuttlefish and octopus have the highest brain-to-body mass ratios of all invertebrates, due to their intelligence, cephalopods are commonly protected by animal testing regulations that do not usually apply to invertebrates. In the UK from 1993 to 2012, the octopus was the only invertebrate protected under the Animals Act 1986. Cephalopods are the only invertebrates protected under the 2010 European Union directive on the protection of animals used for scientific purposes, Octopus intelligence Nautilus intelligence Animal consciousness So you think youre smarter than a cephalopod. By Wendy Williams, At the Smithsonians Ocean Portal, what behavior can we expect of octopuses
20.
Salinity
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Salinity is the saltiness or amount of salt dissolved in a body of water. This is usually measured in g salt k g sea water, a contour line of constant salinity is called an isohaline – or sometimes isohale. Salinity in rivers, lakes, and the ocean is conceptually simple, conceptually the salinity is the quantity of dissolved salt content of the water. Salts are compounds like sodium chloride, magnesium sulfate, potassium nitrate, the concentration of dissolved chloride ions is sometimes referred to as chlorinity. Operationally, dissolved matter is defined as that which can pass through a fine filter. Salinity can be expressed in the form of a mass fraction, Seawater typically has a mass salinity of around 35 g/kg, although lower values are typical near coasts where rivers enter the ocean. Rivers and lakes can have a range of salinities, from less than 0.01 g/kg to a few g/kg. The Dead Sea has a salinity of more than 200 g/kg, whatever pore size is used in the definition, the resulting salinity value of a given sample of natural water will not vary by more than a few percent. A bottled seawater product known as IAPSO Standard Seawater is used by oceanographers to standardize their measurements with enough precision to meet this requirement, measurement and definition difficulties arise because natural waters contain a complex mixture of many different elements from different sources in different molecular forms. The chemical properties of some of these depend on temperature and pressure. Many of these forms are difficult to measure with high accuracy, different practical definitions of salinity result from different attempts to account for these problems, to different levels of precision, while still remaining reasonably easy to use. For many purposes this sum can be limited to a set of eight major ions in natural waters, the major ions dominate the inorganic composition of most natural waters. Exceptions include some pit lakes and waters from some hydrothermal springs, the concentrations of dissolved gases like oxygen and nitrogen are not usually included in descriptions of salinity. However, carbon dioxide gas, which when dissolved is partially converted into carbonates and bicarbonates, is often included. Silicon in the form of acid, which usually appears as a neutral molecule in the pH range of most natural waters. The term salinity is, for oceanographers, usually associated with one of a set of measurement techniques. As the dominant techniques evolve, so do different descriptions of salinity, the distinctions between these different descriptions are important to physical oceanographers but are obscure and confusing to nonspecialists. Salinities were largely measured using titration-based techniques before the 1980s, titration with silver nitrate could be used to determine the concentration of halide ions to give a chlorinity
21.
Stroke volume
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In cardiovascular physiology, stroke volume is the volume of blood pumped from the left ventricle per beat. The term stroke volume can apply to each of the two ventricles of the heart, although it refers to the left ventricle. The stroke volumes for each ventricle are generally equal, both being approximately 70 mL in a healthy 70-kg man, because stroke volume decreases in certain conditions and disease states, stroke volume itself correlates with cardiac function. Its value is obtained by subtracting end-systolic volume from end-diastolic volume for a given ventricle. S V = E D V − E S V In a healthy 70-kg man, ESV is approximately 50 mL and EDV is approximately 120mL, stroke work refers to the work, or pressure of the blood multiplied by the stroke volume. Men, on average, have higher volumes than women due to the larger size of their hearts. However, stroke volume depends on factors such as heart size, contractility, duration of contraction, preload. Prolonged aerobic exercise training may also increase stroke volume, which results in a lower heart rate. Reduced heart rate prolongs ventricular diastole, increasing volume. Stroke volume is controlled by preload. An increase in the volume or speed of venous return will increase preload and, through the Frank–Starling law of the heart, decreased venous return has the opposite effect, causing a reduction in stroke volume. Though not usually affecting stroke volume in healthy individuals, increased afterload will hinder the ventricles in ejecting blood, increased afterload may be found in aortic stenosis and arterial hypertension. Similar to cardiac index, is a method of relating the stroke volume to the size of the person Body surface area. S V I = S V B S A = B S A = C O H R × B S A Berne, Robert M. Levy, cS1 maint, Multiple names, authors list Boron, Walter F. Boulpaep, Emile L. Medical Physiology, A Cellular and Molecular Approach, cS1 maint, Multiple names, authors list The Gross Physiology of the Cardiovascular System The Determinants of Cardiac Output
22.
Metabolism
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Metabolism is the set of life-sustaining chemical transformations within the cells of living organisms. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, usually, breaking down releases energy and building up consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in one chemical is transformed through a series of steps into another chemical. Enzymes act as catalysts that allow the reactions to proceed more rapidly, enzymes also allow the regulation of metabolic pathways in response to changes in the cells environment or to signals from other cells. The metabolic system of a particular organism determines which substances it will find nutritious, for example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the rate, influences how much food an organism will require. A striking feature of metabolism is the similarity of the metabolic pathways. These striking similarities in metabolic pathways are likely due to their appearance in evolutionary history. Most of the structures that make up animals, plants and microbes are made from three classes of molecule, amino acids, carbohydrates and lipids. These biochemicals can be joined together to make such as DNA and proteins. Proteins are made of amino acids arranged in a linear chain joined together by peptide bonds, many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Lipids are the most diverse group of biochemicals and their main structural uses are as part of biological membranes both internal and external, such as the cell membrane, or as a source of energy. Lipids are usually defined as hydrophobic or amphipathic biological molecules but will dissolve in organic solvents such as benzene or chloroform, the fats are a large group of compounds that contain fatty acids and glycerol, a glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Several variations on this structure exist, including alternate backbones such as sphingosine in the sphingolipids. Steroids such as cholesterol are another class of lipids. Carbohydrates are aldehydes or ketones, with hydroxyl groups attached. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy, the basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose
23.
Gill
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A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water and excretes carbon dioxide. The gills of species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a surface area to the external environment. Many microscopic aquatic animals, and some larger but inactive ones, can absorb oxygen through the entire surface of their bodies. However, more complex or more active aquatic organisms usually require a gill or gills, Gills usually consist of thin filaments of tissue, branches, or slender, tufted processes that have a highly folded surface to increase surface area. A high surface area is crucial to the gas exchange of aquatic organisms, a cubic meter of air contains about 250 grams of oxygen at STP. The concentration of oxygen in water is lower than in air, in fresh water, the dissolved oxygen content is approximately 8 cm3/L compared to that of air which is 210 cm3/L. Water is 777 times more dense than air and is 100 times more viscous, oxygen has a diffusion rate in air 10,000 times greater than in water. The use of sac-like lungs to remove oxygen from water would not be efficient enough to sustain life, rather than using lungs, aseous exchange takes place across the surface of highly vascularised gills over which a one-way current of water is kept flowing by a specialised pumping mechanism. The density of the water prevents the gills from collapsing and lying on top of each other, with the exception of some aquatic insects, the filaments and lamellae contain blood or coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body, carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in groups of aquatic animals, including mollusks, crustaceans, insects, fish. The gills of vertebrates typically develop in the walls of the pharynx, most species employ a countercurrent exchange system to enhance the diffusion of substances in and out of the gill, with blood and water flowing in opposite directions to each other. The gills are composed of filaments, the gill lamellae. When a fish breathes, it draws in a mouthful of water at regular intervals, then it draws the sides of its throat together, forcing the water through the gill openings, so it passes over the gills to the outside. Fish gill slits may be the ancestors of the tonsils, thymus glands. Adjacent slits are separated by a gill arch from which projects a cartilaginous gill ray. This gill ray is the support for the sheet-like interbranchial septum, the base of the arch may also support gill rakers, projections into the pharyngeal cavity that help to prevent large pieces of debris from damaging the delicate gills
24.
Lamella (surface anatomy)
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In surface anatomy, a lamella is a thin plate-like structure, often one amongst many lamellae very close to one another, with open space between. Aside from respiratory organs, they appear in other roles including filter feeding. In fish gills there are two types of lamellae, primary and secondary, the primary gill lamellae come out of the interbranchial septum at the fish gill filament to increase the contact area between the water and the blood capillaries that lie in the fish gill filaments. The secondary gill lamellae are small lamellae that come out of the ones and are used to further increase the contact area. Both types of lamellae are used to increase the amount of intake of the blood. Both types of lamellae contain huge amounts of capillaries and are the sites where the exchange of oxygen from the water, pecten – the similar structure in birds
25.
In vitro
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In vitro studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. In contrast, in studies are those conducted in animals, including humans. In vitro studies are conducted using components of an organism that have been isolated from their biological surroundings, such as microorganisms, cells. For example, microrganisms or cells can be studied in artificial culture media, colloquially called test-tube experiments, these studies in biology, medicine, and their subdisciplines are traditionally done in test tubes, flasks, Petri dishes, etc. They now involve the range of techniques used in molecular biology. In contrast, studies conducted in living beings are called in vivo, polymerase chain reaction is a method for selective replication of specific DNA and RNA sequences in the test tube. Protein purification involves the isolation of a protein of interest from a complex mixture of proteins. In vitro fertilization is used to allow spermatozoa to fertilize eggs in a culture dish before implanting the resulting embryo or embryos into the uterus of the prospective mother and these ADME process parameters can then be integrated into so called physiologically based pharmacokinetic models or PBPK. In vitro studies permit a species-specific, simpler, more convenient, just as studies in whole animals more and more replace human trials, so are in vitro studies replacing studies in whole animals. This complexity makes it difficult to identify the interactions between individual components and to explore their basic biological functions, in vitro work simplifies the system under study, so the investigator can focus on a small number of components. Another advantage of in vitro methods is that cells can be studied without extrapolation from an experimental animals cellular response. Investigators doing in vitro work must be careful to avoid over-interpretation of their results, for example, scientists developing a new viral drug to treat an infection with a pathogenic virus may find that a candidate drug functions to prevent viral replication in an in vitro setting. However, before this drug is used in the clinic, it must progress through a series of in vivo trials to determine if it is safe and effective in intact organisms. Results obtained from in vitro experiments cannot usually be transposed, as is, building a consistent and reliable extrapolation procedure from in vitro results to in vivo is therefore extremely important. However, increasingly sophisticated in vitro experiments collect increasingly numerous, complex, mathematical models, such as systems biology models, are much needed here. In pharmacology, IVIVE can be used to approximate pharmacokinetics or pharmacodynamics and that indicates that extrapolating effects observed in vitro needs a quantitative model of in vivo PK. Physiologically based PK models are generally accepted to be central to the extrapolations, in these conditions, developing a simple PD model of the dose–response relationship observed in vitro, and transposing it without changes to predict in vivo effects is not enough
26.
Hemocyanin
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Hemocyanins are proteins that transport oxygen throughout the bodies of some invertebrate animals. These metalloproteins contain two atoms that reversibly bind a single oxygen molecule. They are second only to hemoglobin in frequency of use as a transport molecule. Unlike the hemoglobin in red cells found in vertebrates, hemocyanins are not bound to blood cells but are instead suspended directly in the hemolymph. Oxygenation causes a change between the colorless Cu deoxygenated form and the blue Cu oxygenated form. Hemocyanins are found only in the Mollusca and Arthropoda, the earliest hemocyanins were found in the snail Helix pomatia, also, larval storage proteins in many insects appear to be derived from hemocyanins. The arthropod hemocyanin superfamily is composed of phenoloxidases, hexamerins, pseudohemocyanins or cryptocyanins and these proteins are involved in the process of sclerotization of arthropod cuticle, in wound healing, and humoral immune defense. Phenoloxidase is synthesized by zymogens and are activated by cleaving a N-terminal peptide, hexamerins are storage proteins commonly found in insects. These proteins are synthesized by the fat body and are associated with molting cycles or nutritional conditions. Pseudohemocyanin and cryptocyanins genetic sequences are related to hemocyanins in crustaceans. These proteins have a structure and function, but lack the copper binding sites. The evolutionary changes within the phylogeny of the superfamily are closely related to the emergence of these different proteins in various species. The understanding of proteins within this superfamily would not be understood without the extensive studies of hemocyanin in arthropods. Although the respiratory function of hemocyanin is similar to that of hemoglobin, there are a significant number of differences in its molecular structure, whereas hemoglobin carries its iron atoms in porphyrin rings, the copper atoms of hemocyanin are bound as prosthetic groups coordinated by histidine residues. The active site of hemocyanin is composed of a pair of copper cations which are coordinated to the protein through the driving force of imidazolic rings of six histidine residues. It has been noted that species using hemocyanin for oxygen transportation include crustaceans living in environments with low oxygen pressure. Under these circumstances hemoglobin oxygen transportation is less efficient than hemocyanin oxygen transportation, nevertheless, there are also terrestrial arthropods using hemocyanin, notably spiders and scorpions, that live in warm climates. Most hemocyanins bind with oxygen non-cooperatively and are roughly one-fourth as efficient as hemoglobin at transporting oxygen per amount of blood, Hemoglobin binds oxygen cooperatively due to steric conformation changes in the protein complex, which increases hemoglobins affinity for oxygen when partially oxygenated
27.
Citric acid cycle
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Its central importance to many biochemical pathways suggests that it was one of the earliest established components of cellular metabolism and may have originated abiogenically. The name of this pathway is derived from citric acid that is consumed. In addition, the cycle consumes acetate and water, reduces NAD+ to NADH, the NADH generated by the TCA cycle is fed into the oxidative phosphorylation pathway. The net result of two closely linked pathways is the oxidation of nutrients to produce usable chemical energy in the form of ATP. In eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion, components of the TCA cycle were derived from anaerobic bacteria, and the TCA cycle itself may have evolved more than once. Theoretically there are alternatives to the TCA cycle, however. If several TCA alternatives had evolved independently, they all appear to have converged to the TCA cycle, the citric acid cycle is a key metabolic pathway that connects carbohydrate, fat, and protein metabolism. The reactions of the cycle are carried out by 8 enzymes that completely oxidize acetate, in the form of acetyl-CoA, through catabolism of sugars, fats, and proteins, the two-carbon organic product acetyl-CoA is produced which enters the citric acid cycle. The NADH and FADH2 generated by the citric acid cycle are in used by the oxidative phosphorylation pathway to generate energy-rich adenosine triphosphate. Acetyl-CoA may also be obtained from the oxidation of fatty acids, the citrate then goes through a series of chemical transformations, losing two carboxyl groups as CO2. The carbons lost as CO2 originate from what was oxaloacetate, not directly from acetyl-CoA, the carbons donated by acetyl-CoA become part of the oxaloacetate carbon backbone after the first turn of the citric acid cycle. Loss of the acetyl-CoA-donated carbons as CO2 requires several turns of the citric acid cycle. However, because of the role of the citric acid cycle in anabolism, they not be lost. Most of the energy available by the oxidative steps of the cycle is transferred as energy-rich electrons to NAD+. For each acetyl group that enters the citric cycle, three molecules of NADH are produced. Electrons are also transferred to the electron acceptor Q, forming QH2, at the end of each cycle, the four-carbon oxaloacetate has been regenerated, and the cycle continues. Two carbon atoms are oxidized to CO2, the energy from these reactions is transferred to other processes through GTP. The NADH generated in the TCA cycle may later be oxidized to drive ATP synthesis in a type of process called oxidative phosphorylation, FADH2 is covalently attached to succinate dehydrogenase, an enzyme which functions both in the CAC and the mitochondrial electron transport chain in oxidative phosphorylation
28.
Carbonic acid
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Not to be confused with Carbolic acid, an antiquated name for phenol. Carbonic acid is a compound with the chemical formula H2CO3. It is also a name given to solutions of carbon dioxide in water. In physiology, carbonic acid is described as acid or respiratory acid. It plays an important role in the buffer system to maintain acid–base homeostasis. Carbonic acid, which is an acid, forms two kinds of salts, the carbonates and the bicarbonates. In geology, carbonic acid causes limestone to dissolve producing calcium bicarbonate which leads to many features such as stalactites and stalagmites. It was long believed that carbonic acid could not exist as a pure compound, however, in 1991 it was reported that NASA scientists had succeeded in making solid H2CO3 samples. 7×10−3 in pure water and ≈1. 2×10−3 in seawater. Hence, the majority of the dioxide is not converted into carbonic acid. In the absence of a catalyst, the equilibrium is reached quite slowly, the rate constants are 0.039 s−1 for the forward reaction and 23 s−1 for the reverse reaction. The addition of two molecules of water to CO2 would give orthocarbonic acid, C4, which only in minute amounts in aqueous solution. Addition of base to an excess of acid gives bicarbonate. With excess base, carbonic acid reacts to give carbonate salts, bicarbonate is an intermediate in the transport of CO2 out of the body via respiratory gas exchange. This catalysed reaction is reversed in the lungs, where it converts the bicarbonate back into CO2 and this equilibration plays an important role as a buffer in mammalian blood. A2016 theoretical report suggests that carbonic acid may play a role in protonating various nitrogen bases in blood serum. The oceans of the world have absorbed almost half of the CO2 emitted by humans from the burning of fossil fuels and it has been theorized that the extra dissolved carbon dioxide has caused the oceans average surface pH to shift by about −0.1 unit from pre-industrial levels. This theory is known as acidification, even though the ocean remains basic. Carbonic acid is a polyprotic acid — specifically it is diprotic meaning it has two protons which may dissociate from the parent molecule
29.
Bohr effect
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Since carbon dioxide reacts with water to form carbonic acid, an increase in CO2 results in a decrease in blood pH, resulting in hemoglobin proteins releasing their load of oxygen. Conversely, a decrease in carbon dioxide provokes an increase in pH, in the early 1900s, Christian Bohr was a professor at the University of Copenhagen in Denmark, already well known for his work in the field of respiratory physiology. Hüfner had suggested that the oxygen-haemoglobin binding curve was hyperbolic in shape, but after extensive experimentation, furthermore, in the process of plotting out numerous dissociation curves, it soon became apparent that high partial pressures of carbon dioxide caused the curves to shift to the right. Further experimentation while varying the CO2 concentration quickly provided conclusive evidence, while this has never been proven, Verigo did in fact publish a paper on the haemoglobin-CO2 relationship in 1892. However, his model was flawed, and Bohr harshly criticized it in his own publications. Another challenge to Bohrs discovery comes from within his lab, though there is some evidence to support this, retroactively changing the name of a well-known phenomenon would be extremely impractical, so it remains known as the Bohr effect. The Bohr effect increases the efficiency of transportation through the blood. After hemoglobin binds to oxygen in the due to the high oxygen concentrations. When a tissues metabolic rate increases, so does its carbon dioxide waste production and this causes the pH of the blood to decrease, which promotes the dissociation of oxygen from haemoglobin, and allows the surrounding tissues to obtain enough oxygen to meet their demands. These opposing protonation and deprotonation reactions occur at an equal rate, the Bohr effect enables the body to adapt to changing conditions and makes it possible to supply extra oxygen to tissues that need it the most. For example, when muscles are undergoing strenuous activity, they require large amounts of oxygen to conduct cellular respiration and these waste products lower the pH of the blood, which increases oxygen delivery to the active muscles. Carbon dioxide is not the only molecule that can trigger the Bohr effect, if muscle cells arent receiving enough oxygen for cellular respiration, they resort to lactic acid fermentation, which releases lactic acid as a byproduct. This increases the acidity of the far more than CO2 alone. The magnitude of the Bohr effect is given by the formula Δ l o g Δ p H. Here. The Bohr effect hinges around allosteric interactions between the hemes of the tetramer, a mechanism first proposed by Max Perutz in 1970. Haemoglobin exists in two conformations, a high-affinity R state and a low-affinity T state, when oxygen concentration levels are high, as in the lungs, the R state is favored, enabling the maximum amount of oxygen to be bound to the hemes. In the capillaries, where oxygen levels are lower, the T state is favored. The Bohr effect is dependent on this allostery, as increases in CO2 and H+ help stabilize the T state and this is evidenced by the fact that myoglobin, a monomer with no allostery, does not exhibit the Bohr effect
30.
Diffusion
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Diffusion is the net movement of molecules or atoms from a region of high concentration to a region of low concentration. This is also referred to as the movement of a substance down a concentration gradient, a gradient is the change in the value of a quantity with the change in another variable. The word diffusion derives from the Latin word, diffundere, which means to spread out, a distinguishing feature of diffusion is that it results in mixing or mass transport, without requiring bulk motion. Thus, diffusion should not be confused with convection, or advection, an example of a situation in which bulk flow and diffusion can be differentiated is the mechanism by which oxygen enters the body during external respiration. The lungs are located in the cavity, which expands as the first step in external respiration. This expansion leads to an increase in volume of the alveoli in the lungs and this creates a pressure gradient between the air outside the body and the alveoli. The air moves down the gradient through the airways of the lungs and into the alveoli until the pressure of the air. The air arriving in the alveoli has a concentration of oxygen than the “stale” air in the alveoli. The increase in oxygen concentration creates a concentration gradient for oxygen between the air in the alveoli and the blood in the capillaries that surround the alveoli, oxygen then moves by diffusion, down the concentration gradient, into the blood. The other consequence of the air arriving in alveoli is that the concentration of carbon dioxide in the alveoli decreases and this creates a concentration gradient for carbon dioxide to diffuse from the blood into the alveoli. The pumping action of the heart then transports the blood around the body, as the left ventricle of the heart contracts, the volume decreases, which increases the pressure in the ventricle. This creates a gradient between the heart and the capillaries, and blood moves through blood vessels by bulk flow. The concept of diffusion is widely used in, physics, chemistry, biology, sociology, economics, however, in each case, the object that is undergoing diffusion is “spreading out” from a point or location at which there is a higher concentration of that object. In the phenomenological approach, diffusion is the movement of a substance from a region of high concentration to a region of low concentration without bulk motion, according to Ficks laws, the diffusion flux is proportional to the negative gradient of concentrations. It goes from regions of higher concentration to regions of lower concentration, some time later, various generalizations of Ficks laws were developed in the frame of thermodynamics and non-equilibrium thermodynamics. From the atomistic point of view, diffusion is considered as a result of the walk of the diffusing particles. In molecular diffusion, the molecules are self-propelled by thermal energy. Random walk of small particles in suspension in a fluid was discovered in 1827 by Robert Brown, the theory of the Brownian motion and the atomistic backgrounds of diffusion were developed by Albert Einstein
31.
Epithelium
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Epithelial is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of blood vessels and organs throughout the body, there are three principal shapes of epithelial cell, squamous, columnar, and cuboidal. All glands are made up of epithelial cells, functions of epithelial cells include secretion, selective absorption, protection, transcellular transport, and sensing. Epithelial layers contain no blood vessels, so they must receive nourishment via diffusion of substances from the connective tissue. Cell junctions are well-employed in epithelial tissues, in general, epithelial tissues are classified by the number of their layers and by the shape and function of the cells. The three principal shapes associated with epithelial cells are—squamous, cuboidal and columnar, squamous epithelium has cells that are wider than their height. Cuboidal epithelium has cells whose height and width are approximately the same, columnar epithelium has cells taller than they are wide. However, when taller simple columnar epithelial cells are viewed in cross section showing several nuclei appearing at different heights and this kind of epithelium is therefore described as pseudostratified columnar epithelium. Transitional epithelium has cells that can change from squamous to cuboidal, Simple epithelium is a single layer of cells with every cell in direct contact with the basement membrane that separates it from the underlying connective tissue. In general, it is found where absorption and filtration occur, the thinness of the epithelial barrier facilitates these processes. In general, simple epithelial tissues are classified by the shape of their cells, the four major classes of simple epithelium are, simple squamous, simple cuboidal, simple columnar, pseudostratified. Simple squamous, which is found lining areas where passive diffusion of gases occur, E. g. skin, walls of capillaries, linings of the pericardial, pleural, and peritoneal cavities, as well as the linings of the alveoli of the lungs. Simple cuboidal, these cells may have secretory, absorptive, or excretory functions, examples include small collecting ducts of kidney, pancreas and salivary gland. Simple columnar, cells can be secretory, absorptive, or excretory, Simple columnar epithelium can be ciliated or non-ciliated, ciliated columnar is found in the reproductive tract. Non-ciliated epithelium can also possess microvilli, pseudostratified columnar epithelium, can be ciliated or non-ciliated. The ciliated type is called respiratory epithelium as it is almost exclusively confined to the larger respiratory airways of the nasal cavity, trachea. Stratified epithelium differs from simple epithelium in that it is multilayered and it is therefore found where body linings have to withstand mechanical or chemical insult such that layers can be abraded and lost without exposing subepithelial layers. Cells flatten as the layers become more apical, though in their most basal layers the cells can be squamous, stratified epithelia can have the following specializations, The basic cell types are squamous, cuboidal, and columnar classed by their shape
32.
Aorta
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The aorta is the main artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries. The aorta distributes oxygenated blood to all parts of the body through the systemic circulation, in anatomical sources, the aorta is usually divided into sections. One way of classifying a part of the aorta is by anatomical compartment, the aorta then continues downward as the abdominal aorta diaphragm to the aortic bifurcation. Another system divides the aorta with respect to its course and the direction of blood flow, in this system, the aorta starts as the ascending aorta then travels superiorly from the heart and then makes a hairpin turn known as the aortic arch. Following the aortic arch, the aorta then travels inferiorly as the descending aorta, the descending aorta has two parts. The aorta begins to descend in the cavity, and consequently is known as the thoracic aorta. After the aorta passes through the diaphragm, it is known as the abdominal aorta, the aorta ends by dividing into two major blood vessels, the common iliac arteries and a smaller midline vessel, the median sacral artery. The ascending aorta begins at the opening of the valve in the left ventricle of the heart. It runs through a common pericardial sheath with the pulmonary trunk and these two blood vessels twist around each other, causing the aorta to start out posterior to the pulmonary trunk, but end by twisting to its right and anterior side. The transition from ascending aorta to aortic arch is at the reflection on the aorta. At the root of the aorta, the lumen has three small pockets between the cusps of the aortic valve and the wall of the aorta, which are called the aortic sinuses or the sinuses of Valsalva. The left aortic sinus contains the origin of the coronary artery. Together, these two arteries supply the heart, the posterior aortic sinus does not give rise to a coronary artery. For this reason the left, right and posterior aortic sinuses are also called left-coronary, right-coronary and non-coronary sinuses, in addition to these blood vessels, the aortic arch crosses the left main bronchus. Between the aortic arch and the trunk is a network of autonomic nerve fibers. The left vagus nerve, which passes anterior to the arch, gives off a major branch, the recurrent laryngeal nerve. It then runs back to the neck, the aortic arch has three major branches, from proximal to distal, they are the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. The brachiocephalic trunk supplies the right side of the head and neck as well as the arm and chest wall
33.
Hemoglobin
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Hemoglobin in the blood carries oxygen from the respiratory organs to the rest of the body. There it releases the oxygen to permit aerobic respiration to provide energy to power the functions of the organism in the process called metabolism, in mammals, the protein makes up about 96% of the red blood cells dry content, and around 35% of the total content. Hemoglobin has a capacity of 1.34 mL O2 per gram. The mammalian hemoglobin molecule can bind up to four oxygen molecules, Hemoglobin is involved in the transport of other gases, It carries some of the bodys respiratory carbon dioxide as carbaminohemoglobin, in which CO2 is bound to the globin protein. The molecule also carries the important regulatory molecule nitric oxide bound to a globin protein thiol group, Hemoglobin is also found outside red blood cells and their progenitor lines. Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, in these tissues, hemoglobin has a non-oxygen-carrying function as an antioxidant and a regulator of iron metabolism. Hemoglobin and hemoglobin-like molecules are found in many invertebrates, fungi. In these organisms, hemoglobins may carry oxygen, or they may act to transport and regulate other small molecules and ions such as carbon dioxide, nitric oxide, hydrogen sulfide and sulfide. In 1825 J. F. Engelhard discovered that the ratio of Fe to protein is identical in the hemoglobins of several species, from the known atomic mass of iron he calculated the molecular mass of hemoglobin to n ×16000, the first determination of a proteins molecular mass. This hasty conclusion drew a lot of ridicule at the time from scientists who could not believe that any molecule could be that big, gilbert Smithson Adair confirmed Engelhards results in 1925 by measuring the osmotic pressure of hemoglobin solutions. The oxygen-carrying protein hemoglobin was discovered by Hünefeld in 1840, hemoglobins reversible oxygenation was described a few years later by Felix Hoppe-Seyler. In 1959, Max Perutz determined the structure of myoglobin by X-ray crystallography. This work resulted in his sharing with John Kendrew the 1962 Nobel Prize in Chemistry, the role of hemoglobin in the blood was elucidated by French physiologist Claude Bernard. The name hemoglobin is derived from the heme and globin. Each heme group contains one iron atom, that can bind one oxygen molecule through ion-induced dipole forces, the most common type of hemoglobin in mammals contains four such subunits. Hemoglobin consists of subunits, and these proteins, in turn, are folded chains of a large number of different amino acids called polypeptides. The amino acid sequence of any polypeptide created by a cell is in turn determined by the stretches of DNA called genes, in all proteins, it is the amino acid sequence that determines the proteins chemical properties and function. There is more than one gene, in humans, hemoglobin A is coded for by the genes, HBA1, HBA2
34.
Blood plasma
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Blood plasma is a straw coloured liquid component of blood that normally holds the blood cells in whole blood in suspension, this makes plasma the extracellular matrix of blood cells. It makes up about 55% of the total blood volume. It is the fluid part of extracellular fluid. It is mostly water, and contains dissolved proteins, glucose, clotting factors, electrolytes, hormones, carbon dioxide, Plasma also serves as the protein reserve of the human body. It plays a role in an intravascular osmotic effect that keeps electrolytes in balanced form and protects the body from infection. Blood plasma is prepared by spinning a tube of fresh blood containing an anticoagulant in a centrifuge until the blood fall to the bottom of the tube. The blood plasma is then poured or drawn off, Blood plasma has a density of approximately 1025 kg/m3, or 1.025 g/ml. Blood serum is blood plasma without clotting factors, in other words, plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration. Fresh frozen plasma is on the WHO Model List of Essential Medicines, Blood plasma volume may be expanded by or drained to extravascular fluid when there are changes in Starling forces across capillary walls. For example, when blood pressure drops in circulatory shock, Starling forces drive fluid into the interstitium, standing still for a prolonged period will cause an increase in transcapillary hydrostatic pressure. As a result, approximately 12% of blood plasma volume will cross into the extravascular compartment and this causes an increase in hematocrit, serum total protein, blood viscosity and, as a result of increased concentration of coagulation factors, it causes orthostatic hypercoagulability. The use of plasma as a substitute for whole blood and for transfusion purposes was proposed in March 1918, in the correspondence columns of the British Medical Journal. Dried plasmas in powder or strips of material format were developed, prior to the United States involvement in the war, liquid plasma and whole blood were used. The Blood for Britain program during the early 1940s was quite successful based on Charles Drews contribution, a large project began in August 1940 to collect blood in New York City hospitals for the export of plasma to Britain. Drew was appointed supervisor of the Plasma for Britain project. His notable contribution at this time was to transform the test tube methods of many blood researchers into the first successful mass production techniques. Nonetheless, the decision was made to develop a dried plasma package for the forces as it would reduce breakage and make the transportation, packaging. The resulting dried plasma package came in two tin cans containing 400 cc bottles, one bottle contained enough distilled water to reconstitute the dried plasma contained within the other bottle
35.
Viscosity
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The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the concept of thickness, for example. Viscosity is a property of the fluid which opposes the motion between the two surfaces of the fluid in a fluid that are moving at different velocities. For a given velocity pattern, the stress required is proportional to the fluids viscosity, a fluid that has no resistance to shear stress is known as an ideal or inviscid fluid. Zero viscosity is observed only at low temperatures in superfluids. Otherwise, all fluids have positive viscosity, and are said to be viscous or viscid. A fluid with a high viscosity, such as pitch. The word viscosity is derived from the Latin viscum, meaning mistletoe, the dynamic viscosity of a fluid expresses its resistance to shearing flows, where adjacent layers move parallel to each other with different speeds. It can be defined through the situation known as a Couette flow. This fluid has to be homogeneous in the layer and at different shear stresses, if the speed of the top plate is small enough, the fluid particles will move parallel to it, and their speed will vary linearly from zero at the bottom to u at the top. Each layer of fluid will move faster than the one just below it, in particular, the fluid will apply on the top plate a force in the direction opposite to its motion, and an equal but opposite one to the bottom plate. An external force is required in order to keep the top plate moving at constant speed. The magnitude F of this force is found to be proportional to the u and the area A of each plate. The proportionality factor μ in this formula is the viscosity of the fluid, the ratio u/y is called the rate of shear deformation or shear velocity, and is the derivative of the fluid speed in the direction perpendicular to the plates. Isaac Newton expressed the forces by the differential equation τ = μ ∂ u ∂ y, where τ = F/A. This formula assumes that the flow is moving along parallel lines and this equation can be used where the velocity does not vary linearly with y, such as in fluid flowing through a pipe. Use of the Greek letter mu for the dynamic viscosity is common among mechanical and chemical engineers. However, the Greek letter eta is used by chemists, physicists
36.
Hemolymph
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Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod body remaining in direct contact with the animals tissues. It is composed of a plasma in which hemolymph cells called hemocytes are suspended. In addition to hemocytes, the plasma also contains many chemicals and it is the major tissue type of the open circulatory system characteristic of arthropods. In addition, some such as molluscs possess a hemolymphatic circulatory system. In the grasshopper, the portion of the system consists of tubular hearts. The hearts pump hemolymph into the sinuses of the hemocoel where exchanges of materials take place, the volume of hemolymph needed for such a system is kept to a minimum by a reduction in the size of the body cavity. The hemocoel is divided into chambers called sinuses, coordinated movements of the body muscles gradually bring the hemolymph back to the dorsal sinus surrounding the hearts. Between contractions, tiny valves in the wall of the hearts open, hemolymph fills all of the interior of the animals body and surrounds all cells. When not oxygenated, hemolymph quickly loses its color and appears grey, muscular movements by the animal during locomotion can facilitate hemolymph movement, but diverting flow from one area to another is limited. When the heart relaxes, blood is drawn back toward the heart through open-ended pores called ostia, note that the term ostia is not specific to insect circulation, it literally means doors or openings, and must be understood in context. Hemolymph can contain nucleating agents that confer extra cellular freezing protection, such nucleating agents have been found in the hemolymph of insects of several orders, i. e. Coleoptera, Diptera, and Hymenoptera. Hemolymph is composed of water, inorganic salts, and organic compounds, the primary oxygen transporter molecule is hemocyanin. Arthropod hemolymph contains high levels of amino acids. Most amino acids are present but their relative concentrations vary from species to species, concentrations of amino acids vary according to the arthropod stage of development. An example of this is the silkworm and its need for glycine in the production of silk Proteins present in the hemolymph vary in quantity during the course of development. These proteins are classified by their functions, chroma proteins, protease inhibitors, storage, lipid transport, enzymes, the vitellogenins, some hemolymphic proteins incorporate carbohydrates and lipids into the structure. Nitrogen metabolism end products are present in the hemolymph in low concentrations and these include ammonia, allantoin, uric acid, and urea. Arthropod hormones are present most notably the juvenile hormone, trehalose can be present and sometimes in great amounts along with glucose
37.
Pericardial fluid
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Pericardial fluid is the serous fluid secreted by the serous layer of the pericardium into the pericardial cavity. The pericardium consists of two layers, a fibrous layer and the inner serous layer. This serous layer has two membranes which enclose the pericardial cavity into which is secreted the pericardial fluid, the fluid is similar to the cerebrospinal fluid of the brain which also serves to cushion and allow some movement of the organ. The pericardial fluid reduces friction within the pericardium by lubricating the epicardial surface allowing the membranes to glide over each other with each heart beat, ben-Horin et al. studied the composition of pericardial fluid in patients undergoing open heart surgery. They found that the fluid is made up of a concentration of lactate dehydrogenase, protein. In a healthy adult there is up to 50 ml of clear, however, there is little data on the normal composition of pericardial fluid to serve as a reference. In patients with heart disease there is an accumulation of angiogenic growth factors in the pericardial fluid. These contribute to angiogenesis and arteriogenesis and this helps to prevent myocardial ischemia. A pericardial effusion is the presence of excessive pericardial fluid, this can be confirmed using an echocardiogram, small effusions are not necessarily dangerous and are commonly caused by infection such as HIV or can occur after cardiac surgery. Large and rapidly accumulating effusions may cause cardiac tamponade, a life-threatening complication, pericardiocentesis is a procedure used to remove the pericardial fluid from the pericardial cavity. It is performed using a needle and under the guidance of an ultrasound and this can also be used to treat pericardial effusion or cardiac tamponade
38.
Urine
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Urine is a liquid by-product of metabolism in the bodies of many animals, including humans. It is expelled from the kidneys and flows through the ureters to the urinary bladder, cellular metabolism generates numerous by-products, many nitrogenous, that require clearance from the bloodstream. These by-products are eventually expelled from the body during urination, the method for excreting water-soluble chemicals from the body. These chemicals can be detected and analyzed by urinalysis, of the many such substances that exist, the three main nitrogenous wastes of the mammalian body are urea, uric acid, and creatinine. Animal urine forms part of the nitrogen cycle, in balanced ecosystems it fertilizes soil and plants, which in turn continue to support the animal population. Some animals use it to mark their territories, human urine and human feces are collectively referred to as human waste, as sewage, they require sewage treatment in places where population density is high. Livestock urine and feces similarly require proper management if the population density is high. Such management is part of ecological sanitation, most animals have excretory systems for elimination of soluble toxic wastes. In humans, soluble wastes are excreted primarily by the system and, to a lesser extent in terms of urea. The urinary system consists of the kidneys, ureters, urinary bladder, the system produces urine by a process of filtration, reabsorption, and tubular secretion. The kidneys extract the soluble wastes from the bloodstream, as well as water, sugars. The resulting urine contains high concentrations of urea and other substances, urine flows from the kidney through the ureter, bladder, and finally the urethra before passing from the body. Research looking at the duration of urination in a range of species found that 9 larger species urinated for 21 ±13 seconds irrespective of body size. Smaller species including rodents and bats cannot produce jets and instead urinate with a series of drops, producing too much or too little urine needs medical attention. Polyuria is a condition of excessive production of urine, oliguria when <400 mL are produced, about 91-96% of urine consists of water. Urine also contains an assortment of inorganic salts and organic compounds, including proteins, hormones, the total solids in urine are on average 59 g per person per day. Organic matter makes up between 65% and 85% of urine dry solids, with volatile solids comprising 75–85% of total solids, urea is the largest constituent of the solids, constituting more than 50% of the total. On an elemental level, human urine contains 6.87 g/L carbon,8.12 g/L nitrogen,8.25 g/L oxygen, the exact proportions vary with individuals and with factors such as diet and health
39.
Osmoregulation
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Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the pressure of a solution, the more water tends to move into it. Pressure must be exerted on the side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water. Two major types of osmoregulation are osmoconformers and osmoregulators, osmoconformers match their body osmolarity to their environment actively or passively. Most marine invertebrates are osmoconformers, although their ionic composition may be different from that of seawater, osmoregulators tightly regulate their body osmolarity, maintaining constant internal conditions. They are more common in the animal kingdom, osmoregulators actively control salt concentrations despite the salt concentrations in the environment. The gills actively uptake salt from the environment by the use of mitochondria-rich cells, water will diffuse into the fish, so it excretes a very hypotonic urine to expel all the excess water. A marine fish has an internal osmotic concentration lower than that of the seawater, so it tends to lose water. It actively excretes salt out from the gills, most fish are stenohaline, which means they are restricted to either salt or fresh water and cannot survive in water with a different salt concentration than they are adapted to. However, some show a tremendous ability to effectively osmoregulate across a broad range of salinities, fish with this ability are known as euryhaline species. Flounder have been observed to inhabit two utterly disparate environments — marine and fresh water — and it is inherent to adapt to both by bringing in behavioral and physiological modifications. Some marine fish, like sharks, have adopted a different, efficient mechanism to conserve water and they retain urea in their blood in relatively higher concentration. Urea damages living tissues so, to cope with this problem and this provides a better solution to ureas toxicity. Sharks, having slightly higher concentration, do not drink water like fresh water fish. Strong winds, low humidity and high temperatures all increase evapotranspiration from leaves, abscisic acid is an important hormone in helping plants to conserve water — it causes stomata to close and stimulates root growth so that more water can be absorbed. Plants share with animals the problems of obtaining water but, unlike in animals, certain plants have evolved methods of water conservation. Xerophytes are plants that can survive in dry habitats, such as deserts, succulent plants such as the cacti store water in the vacuoles of large parenchyma tissues. Other plants have modifications to reduce water loss, such as needle-shaped leaves, sunken stomata
40.
Osmotic pressure
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Osmotic pressure is the minimum pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane. It is also defined as the measure of the tendency of a solution to take in water by osmosis, potential osmotic pressure is the maximum osmotic pressure that could develop in a solution if it were separated from distilled water by a selectively permeable membrane. The phenomenon of osmosis arises from the propensity of a solvent to move through a semi-permeable membrane. This process is of importance in biology as the cells membrane is semipermeable. Sugar has been added to the water on one side and this process will stop once the pressures of the water and sugar water on both sides of the membrane become equal. T is the temperature in kelvins and this formula states that osmotic pressure is simply proportional to the solute concentration. It applies when the concentration is sufficiently low that the solution can be treated as an ideal solution. The proportionality to concentration means that pressure is a colligative property. Van t Hoff was the first recipient of the Nobel prize for chemistry for his work on osmotic pressure, a simple extension of this equation was proposed by Harmon Northrop Morse Π = i c solutes R T, where i is a dimensionless correction factor. This formula extends the range of applicability to more concentrated solutions. Historically, van t Hoffs law and osmotic pressure measurement have been used for the molecular weights. The Pfeffer cell was developed for the measurement of pressure in biology. Osmotic pressure is an important factor affecting cells, osmoregulation is the homeostasis mechanism of an organism to reach balance in osmotic pressure. Hypertonicity is the presence of a solution that causes cells to shrink, hypotonicity is the presence of a solution that causes cells to swell. Isotonicity is the presence of a solution that produces no change in cell volume, when a biological cell is in a hypotonic environment, the cell interior accumulates water, water flows across the cell membrane into the cell, causing it to expand. In plant cells, the cell wall restricts the expansion, resulting in pressure on the wall from within called turgor pressure. Turgor pressure allows plants to stand upright. It is also the factor for how plants regulate the aperture of their stomata
41.
Ion
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An ion is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge. Ions can be created, by chemical or physical means. In chemical terms, if an atom loses one or more electrons. If an atom gains electrons, it has a net charge and is known as an anion. Ions consisting of only a single atom are atomic or monatomic ions, because of their electric charges, cations and anions attract each other and readily form ionic compounds, such as salts. In the case of ionization of a medium, such as a gas, which are known as ion pairs are created by ion impact, and each pair consists of a free electron. The word ion comes from the Greek word ἰόν, ion, going and this term was introduced by English physicist and chemist Michael Faraday in 1834 for the then-unknown species that goes from one electrode to the other through an aqueous medium. Faraday also introduced the words anion for a charged ion. In Faradays nomenclature, cations were named because they were attracted to the cathode in a galvanic device, arrhenius explanation was that in forming a solution, the salt dissociates into Faradays ions. Arrhenius proposed that ions formed even in the absence of an electric current, ions in their gas-like state are highly reactive, and do not occur in large amounts on Earth, except in flames, lightning, electrical sparks, and other plasmas. These gas-like ions rapidly interact with ions of charge to give neutral molecules or ionic salts. These stabilized species are commonly found in the environment at low temperatures. A common example is the present in seawater, which are derived from the dissolved salts. Electrons, due to their mass and thus larger space-filling properties as matter waves, determine the size of atoms. Thus, anions are larger than the parent molecule or atom, as the excess electron repel each other, as such, in general, cations are smaller than the corresponding parent atom or molecule due to the smaller size of its electron cloud. One particular cation contains no electrons, and thus consists of a single proton - very much smaller than the parent hydrogen atom. Since the electric charge on a proton is equal in magnitude to the charge on an electron, an anion, from the Greek word ἄνω, meaning up, is an ion with more electrons than protons, giving it a net negative charge. A cation, from the Greek word κατά, meaning down, is an ion with fewer electrons than protons, there are additional names used for ions with multiple charges
