1.
Latin
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Latin is a classical language belonging to the Italic branch of the Indo-European languages. The Latin alphabet is derived from the Etruscan and Greek alphabets, Latin was originally spoken in Latium, in the Italian Peninsula. Through the power of the Roman Republic, it became the dominant language, Vulgar Latin developed into the Romance languages, such as Italian, Portuguese, Spanish, French, and Romanian. Latin, Italian and French have contributed many words to the English language, Latin and Ancient Greek roots are used in theology, biology, and medicine. By the late Roman Republic, Old Latin had been standardised into Classical Latin, Vulgar Latin was the colloquial form spoken during the same time and attested in inscriptions and the works of comic playwrights like Plautus and Terence. Late Latin is the language from the 3rd century. Later, Early Modern Latin and Modern Latin evolved, Latin was used as the language of international communication, scholarship, and science until well into the 18th century, when it began to be supplanted by vernaculars. Ecclesiastical Latin remains the language of the Holy See and the Roman Rite of the Catholic Church. Today, many students, scholars and members of the Catholic clergy speak Latin fluently and it is taught in primary, secondary and postsecondary educational institutions around the world. The language has been passed down through various forms, some inscriptions have been published in an internationally agreed, monumental, multivolume series, the Corpus Inscriptionum Latinarum. Authors and publishers vary, but the format is about the same, volumes detailing inscriptions with a critical apparatus stating the provenance, the reading and interpretation of these inscriptions is the subject matter of the field of epigraphy. The works of several hundred ancient authors who wrote in Latin have survived in whole or in part and they are in part the subject matter of the field of classics. The Cat in the Hat, and a book of fairy tales, additional resources include phrasebooks and resources for rendering everyday phrases and concepts into Latin, such as Meissners Latin Phrasebook. The Latin influence in English has been significant at all stages of its insular development. From the 16th to the 18th centuries, English writers cobbled together huge numbers of new words from Latin and Greek words, dubbed inkhorn terms, as if they had spilled from a pot of ink. Many of these words were used once by the author and then forgotten, many of the most common polysyllabic English words are of Latin origin through the medium of Old French. Romance words make respectively 59%, 20% and 14% of English, German and those figures can rise dramatically when only non-compound and non-derived words are included. Accordingly, Romance words make roughly 35% of the vocabulary of Dutch, Roman engineering had the same effect on scientific terminology as a whole
2.
Anatomical terminology
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Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors. Anatomical terminology uses many terms, suffixes, and prefixes deriving from Ancient Greek. These terms can be confusing to those unfamiliar with them, but can be more precise reducing ambiguity, also, since these anatomical terms are not used in everyday conversation, their meanings are less likely to change, and less likely to be misinterpreted. By using precise anatomical terminology such ambiguity is eliminated, an international standard for anatomical terminology, Terminologia Anatomica has been created. Anatomical terminology has quite regular morphology, the prefixes and suffixes are used to add meanings to different roots. The root of a term refers to an organ, tissue. For example, in the disorder hypertension, the prefix hyper- means high or over, the roots, prefixes and suffixes are often derived from Greek or Latin, and often quite dissimilar from their English-language variants. Latin names of such as musculus biceps brachii can be split up and refer to, musculus for muscle, biceps for two-headed. The first word tells us what we are speaking about, the second describes it, when describing the position of anatomical structures, structures may be described according to the anatomical landmark they are near. These landmarks may include structures, such as the umbilicus or sternum, or anatomical lines, the cephalon or cephalic region refers to the head. This area is differentiated into the cranium, facies, frons, oculus, auris, bucca, nausus, oris. The neck area is called the cervicis or cervical region, examples of structures named according to this include the frontalis muscle, submental lymph nodes, buccal membrane and orbicularis oculi muscle. Sometimes, unique terminology is used to reduce confusion in different parts of the body, for example, different terms are used when it comes to the skull in compliance with its embryonic origin and its tilted position compared to in other animals. Here, Rostral refers to proximity to the front of the nose, similarly, in the arms, different terminology is often used in the arms, in part to reduce ambiguity as what is the front, back, inner and outer surfaces. For this reason, the terms below are used, Radial referring to the radius bone, ulnar referring to the ulna bone, medially positioned when in the standard anatomical position. Other terms are used to describe the movement and actions of the hands and feet. International morphological terminology is used by the colleges of medicine and dentistry and it facilitates communication and exchanges between scientists from different countries of the world and it is used daily in the fields of research, teaching and medical care. The international morphological terminology refers to morphological sciences as a biological sciences branch, in this field, the form and structure are examined as well as the changes or developments in the organism
3.
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
4.
Mammal
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Mammals are any vertebrates within the class Mammalia, a clade of endothermic amniotes distinguished from reptiles by the possession of a neocortex, hair, three middle ear bones and mammary glands. All female mammals nurse their young with milk, secreted from the mammary glands, Mammals include the largest animals on the planet, the great whales. The basic body type is a quadruped, but some mammals are adapted for life at sea, in the air, in trees. The largest group of mammals, the placentals, have a placenta, Mammals range in size from the 30–40 mm bumblebee bat to the 30-meter blue whale. With the exception of the five species of monotreme, all modern mammals give birth to live young, most mammals, including the six most species-rich orders, belong to the placental group. The largest orders are the rodents, bats and Soricomorpha, the next three biggest orders, depending on the biological classification scheme used, are the Primates, the Cetartiodactyla, and the Carnivora. Living mammals are divided into the Yinotheria and Theriiformes There are around 5450 species of mammal, in some classifications, extant mammals are divided into two subclasses, the Prototheria, that is, the order Monotremata, and the Theria, or the infraclasses Metatheria and Eutheria. The marsupials constitute the group of the Metatheria, and include all living metatherians as well as many extinct ones. Much of the changes reflect the advances of cladistic analysis and molecular genetics, findings from molecular genetics, for example, have prompted adopting new groups, such as the Afrotheria, and abandoning traditional groups, such as the Insectivora. The mammals represent the only living Synapsida, which together with the Sauropsida form the Amniota clade, the early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period, this group diverged from the line that led to todays reptiles. Some mammals are intelligent, with some possessing large brains, self-awareness, Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent-marking, alarm signals, singing, and echolocation. Mammals can organize themselves into fission-fusion societies, harems, and hierarchies, most mammals are polygynous, but some can be monogamous or polyandrous. They provided, and continue to provide, power for transport and agriculture, as well as commodities such as meat, dairy products, wool. Mammals are hunted or raced for sport, and are used as model organisms in science, Mammals have been depicted in art since Palaeolithic times, and appear in literature, film, mythology, and religion. Defaunation of mammals is primarily driven by anthropogenic factors, such as poaching and habitat destruction, Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is accepted, McKenna & Bell and Wilson & Reader provide useful recent compendiums. Though field work gradually made Simpsons classification outdated, it remains the closest thing to a classification of mammals
5.
Menstruation
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Menstruation, also known as a period or monthly, is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The first period usually begins between twelve and fifteen years of age, a point in time known as menarche, however, periods may occasionally start as young as eight years old and still be considered normal. The average age of the first period is later in the developing world. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, bleeding usually lasts around 2 to 7 days. Menstruation stops occurring after menopause, which occurs between 45 and 55 years of age. Periods also stop during pregnancy and typically do not resume during the months of breastfeeding. Up to 80% of women report having some symptoms prior to menstruation, common signs and symptoms include acne, tender breasts, bloating, feeling tired, irritability, and mood changes. These may interfere with life, therefore qualifying as premenstrual syndrome. In 3 to 8%, symptoms are severe, a lack of periods, known as amenorrhea, is when periods do not occur by age 15 or have not occurred in 90 days. Other problems with the cycle include painful periods and abnormal bleeding such as bleeding between periods or heavy bleeding. Menstruation in other animals occurs in primates, such as apes and monkeys, as well as bats, the menstrual cycle occurs due to the rise and fall of hormones. This cycle results in the thickening of the lining of the uterus, the egg is released from an ovary around day fourteen in the cycle, the thickened lining of the uterus provides nutrients to an embryo after implantation. If pregnancy does not occur, the lining is released in what is known as menstruation, the first menstrual period occurs after the onset of pubertal growth, and is called menarche. The average age of menarche is 12 to 15, however, it may start as early as eight. The average age of the first period is later in the developing world. The average age of menarche has changed little in the United States since the 1950s, Menstruation is the most visible phase of the menstrual cycle and its beginning is used as the marker between cycles. The first day of bleeding is the date used for the last menstrual period. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, the medical definition of menopause is one year without a period and typically occurs between 45 and 55 in Western countries
6.
Ape
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The simians are the monkeys, cladistically including the apes, the New World monkeys or platyrrhines, and the catarrhine clade consisting of the Old World monkeys and apes. The simian line and the line diverged about 60 million years ago. Forty million years ago, simians from Africa colonized South America, the remaining simians split 25 million years ago into apes and Old World monkeys. Under modern classification, the tarsiers and simians are grouped under the suborder Haplorhini while the strepsirrhines are placed in suborder Strepsirrhini, in anthropoidea, evidences indicate that the Old and the New World primates went through parallel evolution. Primatology, paleoanthropology, and other related fields are split on their usage of the synonymous infraorder names, Simiiformes and Anthropoidea. According to Robert Hoffstetter, the term Simiiformes has priority over Anthropoidea because of the taxonomic term Simii by van der Hoeven, from which it is constructed, dates to 1833. In contrast, Anthropoidea by Mivart dates to 1864, while Simiiformes by Haeckel dates to 1866, Hoffstetter also argued that Simiiformes is also constructed like a proper infraorder name, whereas Anthropoidea ends in -oidea, which is reserved for superfamilies. He also noted that Anthropoidea is too easily confused with anthropoïdes, the simians are split into three distinct groups. The New World monkeys in parvorder Platyrrhini split from the rest of the line about 40 mya. This group split about 25 mya between the Old World monkeys and the apes
7.
Old World monkey
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The Old World monkeys or Cercopithecidae are a family of catarrhines, the only family in the superfamily Cercopithecoidea in the clade of Catarrhini. However, a group of monkeys still survives in Gibraltar to this day. Old World monkeys include many of the most familiar species of primates, such as baboons. Old World monkeys are medium to large in size, and range from arboreal forms, such as the monkeys, to fully terrestrial forms. By superficial appearance, Old World monkeys are unlike apes in that most have tails and, unlike the New World monkeys, technically, the distinction of catarrhines from platyrrhines depends on the structure of the nose, and the distinction of Old World monkeys from apes depends on dentition. In platyrrhines, the nostrils face sideways, while in catarrhines, for example, the colobus monkeys have stubs for thumbs to assist with their arboreal movement, the proboscis monkey has an extraordinary nose, while the snub-nosed monkeys have almost no nose at all. The male mandrills penis is red and the scrotum is lilac, the coloration is more pronounced in dominant males. Most Old World monkeys are at least partially omnivorous, but all prefer plant matter, the Barbary macaques diet consists mostly of leaves and roots, though it will also eat insects and uses cedar trees as a water source. Gestation in the Old World monkeys lasts between five and seven months, births are usually single, although, as with humans, twins occur from time to time. The young are born relatively well-developed, and are able to cling onto their mothers fur with their hands from birth, compared with most other mammals, they take a long time to reach sexual maturity, with four to six years being typical of most species. In most species, daughters remain with their mothers for life, males leave the group on reaching adolescence, and find a new troop to join. In many species, only an adult male lives with each group, driving off all rivals. Group sizes are variable, even within species, depending on the availability of food. Therefore, cladistically, apes, catarrhines and related contemporary extinct groups such as Parapithecidaea are monkeys as well, for any consistent definition of monkey
8.
Bat
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Bats are mammals of the order Chiroptera whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, Bats do not flap their entire forelimbs, as birds do, but instead flap their spread-out digits, which are very long and covered with a thin membrane or patagium. About 70% of bat species are insectivores, most of the rest are frugivores, or fruit eaters. A few species, such as the bat, feed from animals other than insects, with the vampire bats being hematophagous. Bats are present throughout most of the world, with the exception of cold regions. They perform the vital roles of pollinating flowers and dispersing fruit seeds. Bats are economically important, as they consume insect pests, reducing the need for pesticides, the smallest bat is the Kittis hog-nosed bat, measuring 29–34 mm in length,15 cm across the wings and 2–2.6 g in mass. It is also arguably the smallest extant species of mammal, with the Etruscan shrew being the other contender. The largest species of bat are a few species of Pteropus, the Mexican free-tailed bat is the fastest flying animal in horizontal flight. An older English name for bats is flittermouse, which matches their name in other Germanic languages, middle English had bakke, most likely cognate with Old Swedish natbakka, which may have undergone a shift from -k- to -t- influenced by Latin blatta, moth, nocturnal insect. They were formerly grouped in the superorder Archonta, along with the treeshrews, colugos, genetic studies have now placed bats in the superorder Laurasiatheria, along with carnivorans, pangolins, odd-toed ungulates, even-toed ungulates, and cetaceans. A recent study by Zhang et al. places Chiroptera as a taxon to the clade Perissodactyla. The phylogenetic relationships of the different groups of bats have been the subject of much debate and this hypothesis recognized differences between microbats and megabats and acknowledged that flight has only evolved once in mammals. Most molecular biological evidence supports the view that bats form a single or monophyletic group, in the 1980s, a hypothesis based on morphological evidence was offered that stated the Megachiroptera evolved flight separately from the Microchiroptera. The so-called flying primate hypothesis proposes that, when adaptations to flight are removed, one example is that the brains of megabats show a number of advanced characteristics that link them to primates. Although recent genetic studies support the monophyly of bats, debate continues as to the meaning of available genetic. Genetic evidence indicates that megabats originated during the early Eocene and should be placed within the four lines of microbats. Consequently, two new suborders based on molecular data have been proposed and these two new suborders are strongly supported by statistical tests
9.
Elephant shrew
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One species, the North African elephant shrew, remains in the semiarid, mountainous country in the far northwest of the continent. The creature is one of the fastest small mammals, despite their weight of under half a kilogram, they have been recorded to reach speeds of 28.8 km/h. They vary in size from about 10 cm to almost 30 cm, the short-eared elephant shrew has an average size of 150 mm. Although the size of the trunk varies among species, all are able to twist it about in search of food and their lifespans are about two and a half to four years in the wild. They have large teeth, and also high-crowned cheek teeth similar to those of ungulates. Several species make a series of cleared pathways through the undergrowth, if disturbed, the pathway provides an obstacle-free escape route. Elephant shrews are not highly social animals, but many live in monogamous pairs, rhynchocyon species also dig small conical holes in the soil, bandicoot-style, but others may make use of natural crevices, or make leaf nests. Short-eared elephant shrews inhabit the dry steppes and stone deserts of southwestern Africa and they can even be found in the Namib Desert, one of the driest regions of the earth. Females drive away other females, while try to ward off other males. Although they live in pairs, the partners do not care much for each other, social behaviors are not very common and they even have separate nests. The one or two young are developed at birth, they are able to run within a few hours. Female elephant shrews undergo a cycle similar to that of human females. The elephant shrew mating period lasts for several days, after mating, the pair will return to their solitary habits. After a gestation period varying from 45 to 60 days, the female bear litters of one to three young several times a year. The young are relatively well developed, but remain in the nest for several days before venturing outside. After five days, the youngs milk diet is supplemented with mashed insects, the young then slowly start to explore their environment and hunt for insects. After about 15 days, the young begin the migratory phase of their lives. The young will then establish their own home ranges and will become active within 41–46 days
10.
Estrous cycle
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The estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases or pregnancies, typically, estrous cycles continue until death. Some animals may display bloody vaginal discharge, often mistaken for menstruation, however, species vary significantly in the detailed functioning. One difference is that animals that have estrous cycles reabsorb the endometrium if conception does not occur during that cycle, animals that have menstrual cycles shed the endometrium through menstruation instead. In species with estrous cycles, females are generally only sexually active during the phase of their cycle. This is also referred to as being in heat, in contrast, females of species with menstrual cycles can be sexually active at any time in their cycle, even when they are not about to ovulate. Humans have menstrual cycles rather than estrous cycles and they, unlike other species, were thought to not have any obvious external signs to signal estral receptivity at ovulation. Some research suggests, however, that tend to have more sexual thoughts and are far more prone to sexual activity right before ovulation. Estrus is derived via Latin oestrus, from Greek οἶστρος, specifically, this refers to the gadfly that Hera sent to torment Io, who had been won in her heifer form by Zeus. Euripides used oestrus to indicate frenzy, and to describe madness, homer uses the word to describe panic. Plato also uses it to refer to a drive and to describe the soul driven. Somewhat more closely aligned to current meaning and usage of estrus, Herodotus uses oistros to describe the desire of fish to spawn, the earliest use in English is of frenzied passion. In 1900 it was first used to describe rut in animals, in British English, the spelling is oestrus or œstrus. In all English spellings, the ends in -us and the adjective in -ous. Thus in American English, a mammal may be described as in estrus when it is in particular part of the estrous cycle. Estrum is sometimes used as a synonym for estrus, one or several follicles of the ovary start to grow. Typically this phase can last as little as one day or as long as three weeks, depending on the species, under the influence of estrogen the lining in the uterus starts to develop. Some animals may experience vaginal secretions that could be bloody, estrus refers to the phase when the female is sexually receptive
11.
Blood vessel
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The blood vessels are the part of the circulatory system that transports blood throughout the human body. The word vascular, meaning relating to the vessels, is derived from the Latin vas. A few structures do not contain blood vessels and are labeled, tunica media, circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina. The tunica media may be rich in smooth muscle, which controls the caliber of the vessel. Veins dont have the external elastic lamina, but only an internal one, tunica adventitia, entirely made of connective tissue. It also contains nerves that supply the vessel as well as nutrient capillaries in the blood vessels. Capillaries consist of more than a layer of endothelium and occasional connective tissue. When blood vessels connect to form a region of diffuse vascular supply it is called an anastomosis, anastomoses provide critical alternative routes for blood to flow in case of blockages. There is a layer of muscle surrounding the arteries and the veins which help contract and this creates enough pressure for blood to be pumped around the body. Blood vessels are part of the system, together with the heart. They are roughly grouped as arterial and venous, determined by whether the blood in it is flowing away from or toward the heart. The term arterial blood is used to indicate blood high in oxygen. This is because they are carrying the blood to and from the lungs, respectively, blood vessels do not actively engage in the transport of blood, but arteries—and veins to a degree—can regulate their inner diameter by contraction of the muscular layer. This changes the flow to downstream organs, and is determined by the autonomic nervous system. Vasodilation and vasoconstriction are also used antagonistically as methods of thermoregulation, oxygen is the most critical nutrient carried by the blood. In all arteries apart from the artery, hemoglobin is highly saturated with oxygen. In all veins apart from the vein, the hemoglobin is desaturated at about 75%. The blood pressure in blood vessels is traditionally expressed in millimetres of mercury, in the arterial system, this is usually around 120 mmHg systolic and 80 mmHg diastolic
12.
Placenta
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The placenta provides oxygen and nutrients to growing babies and removes waste products from the babys blood. The placenta attaches to the wall of the uterus, and the umbilical cord develops from the placenta. The umbilical cord is what connects the mother and the baby, Placentas are a defining characteristic of placental mammals, but are also found in some non-mammals with varying levels of development. The homology of structures in various viviparous organisms is debatable. The classical plural is placentae, but the form placentas is common in modern English, prototherial and metatherial mammals produce a choriovitelline placenta that, while connected to the uterine wall, provides nutrients mainly derived from the egg sac. In humans, the placenta averages 22 cm in length and 2–2.5 cm in thickness, with the center being the thickest, and it typically weighs approximately 500 grams. It has a dark reddish-blue or crimson color and it connects to the fetus by an umbilical cord of approximately 55–60 cm in length, which contains two umbilical arteries and one umbilical vein. The umbilical cord inserts into the chorionic plate, vessels branch out over the surface of the placenta and further divide to form a network covered by a thin layer of cells. This results in the formation of villous tree structures, on the maternal side, these villous tree structures are grouped into lobules called cotyledons. In humans, the placenta usually has a shape. The placental flora more closely resembles that of the oral microbiome than either the vaginal or rectal microbiome, in non-human animals, part of the microbiome is passed onto offspring even before the offspring are born. Bacteriologists assume that the same holds true for humans. The placenta begins to develop upon implantation of the blastocyst into the maternal endometrium, the outer layer of the blastocyst becomes the trophoblast, which forms the outer layer of the placenta. This outer layer is divided into two layers, the underlying cytotrophoblast layer and the overlying syncytiotrophoblast layer. The syncytiotrophoblast is a continuous cell layer that covers the surface of the placenta. It forms as a result of differentiation and fusion of the underlying cytotrophoblast cells, the syncytiotrophoblast, thereby contributes to the barrier function of the placenta. Development of the blood supply to the placenta is complete by the end of the first trimester of pregnancy. In preparation for implantation of the blastocyst, the uterine endometrium undergoes decidualisation, spiral arteries in decidua are remodeled so that they become less convoluted and their diameter is increased
13.
Oxygen
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Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
14.
Embryo
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An embryo is an early stage of development of a multicellular diploid eukaryotic organism. In general, in organisms that reproduce sexually, an embryo develops from a zygote, the zygote possesses half the DNA of each of its two parents. In plants, animals, and some protists, the zygote will begin to divide by mitosis to produce a multicellular organism, the result of this process is an embryo. First attested in English in the mid-14c, the word embryon derives from Medieval Latin embryo, itself from Greek ἔμβρυον, lit. Young one, which is the neuter of ἔμβρυος, lit, growing in, from ἐν, in and βρύω, swell, be full, the proper Latinized form of the Greek term would be embryum. In animals, the development of the zygote into an embryo proceeds through specific stages of blastula, gastrula. The blastula stage typically features a fluid-filled cavity, the blastocoel, surrounded by a sphere or sheet of cells, in a placental mammal, an ovum is fertilized in a fallopian tube through which it travels into the uterus. An embryo is called a fetus at an advanced stage of development. In humans, this is from the week of gestation. During gastrulation the cells of the blastula undergo coordinated processes of cell division, invasion, in triploblastic organisms, the three germ layers are called endoderm, ectoderm, and mesoderm. The position and arrangement of the layers are highly species-specific, however. For example, in neurogenesis, a subpopulation of cells is set aside to become the brain, spinal cord. Modern developmental biology is extensively probing the molecular basis for every type of organogenesis, including angiogenesis, chondrogenesis, myogenesis, osteogenesis, and many others. In botany, a plant embryo is part of a seed, consisting of precursor tissues for the leaves, stem. Once the embryo begins to germinate — grow out from the seed — it is called a seedling, bryophytes and ferns also produce an embryo, but do not produce seeds. In these plants, the embryo begins its existence attached to the inside of the archegonium on a parental gametophyte from which the egg cell was generated, the structure and development of the rest of the embryo varies by group of plants. Once the embryo has expanded beyond the enclosing archegonium, it is no longer termed an embryo, embryos are used in various fields of research and in techniques of assisted reproductive technology. An egg may be fertilized in vitro and the embryo may be frozen for later use
15.
Fetus
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A fetus is a stage in the prenatal development of viviparous organisms. In human development, a fetus or foetus is a human between the embryonic state and birth. The fetal stage of development tends to be taken as beginning at the age of eleven weeks. In biological terms, however, prenatal development is a continuum, the use of the term fetus generally implies that an embryo has developed to the point of being recognizable as a human, this is the point usually taken to be the ninth week after fertilization. A fetus is also characterized by the presence of all the body organs, though they will not yet be fully developed and functional. The word fetus is from the Latin fētus, the British, Irish, and Commonwealth spelling is foetus, which has been in use since at least 1594. It arose as a hypercorrection based on an incorrect etymology that may have originated with an error by Isidore of Seville in AD620 and this spelling is the most common in most Commonwealth nations, except in the medical literature, where fetus is used. The etymologically accurate original spelling fetus is used in Canada and the United States, in addition, fetus is now the standard English spelling throughout the world in medical journals. The spelling faetus was used historically, in humans, the fetal stage commences at the beginning of the ninth week. At the start of the stage, the fetus is typically about 30 millimetres in length from crown to rump. The head makes up half of the fetus size. Breathing-like movement of the fetus is necessary for stimulation of lung development, the heart, hands, feet, brain and other organs are present, but are only at the beginning of development and have minimal operation. The genitalia of the starts to form and placenta becomes fully functional during week 9. At this point in development, uncontrolled movements and twitches occur as muscles, the brain, and pathways begin to develop. A woman pregnant for the first time, typically feels fetal movements at about 21 weeks, whereas a woman who has given birth at least once, by the end of the fifth month, the fetus is about 20 cm long. The amount of body fat rapidly increases, thalamic brain connections, which mediate sensory input, form. Bones are fully developed, but are soft and pliable. Iron, calcium, and phosphorus become more abundant, fingernails reach the end of the fingertips
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Micrograph
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A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an item. This is opposed to an image, which is at a scale that is visible to the naked eye. Micrography is the practice or art of using microscopes to make photographs, a micrograph contains extensive details that form the features of a microstructure. The neuropathologist Solomon C. Fuller designed and created the first photomicrograph in 1900, micrographs are widely used in all fields of microscopy. A light micrograph or photomicrograph is a micrograph prepared using an optical microscope, at a basic level, photomicroscopy may be performed simply by hooking up a regular camera to a microscope, thereby enabling the user to take photographs at reasonably high magnification. Roman Vishniac was a pioneer in the field of photomicroscopy, specializing in the photography of living creatures in full motion and he also made major developments in light-interruption photography and color photomicroscopy. An electron micrograph is a micrograph prepared using an electron microscope, however, the term electron micrograph is not used in electron microscopy. Digital micrography is a digital picture obtained either directly with a microscope or by scanning of a photomicrograph, digital micrographs are now commonly obtained using a USB microscope attached directly to a home computer or laptop. Today, an add-on three-in-one macro lens which has capability to take wide-angle, fish-eye and macro with 7x, 14x, micrographs usually have micron bars, or magnification ratios, or both. Magnification is a ratio between size of object on a picture and its real size, unfortunately, magnification is somewhat a misleading parameter. It depends on a size of a printed picture. Editors of journals and magazines routinely resize a figure to fit the page, a scale bar, or micron bar, is a bar of known length displayed on a picture. The bar can be used for measurements on a picture, when a picture is resized a bar is also resized. If a picture has a bar, the magnification can be easily calculated, ideally, all pictures destined for publication/presentation should be supplied with a scale bar, the magnification ratio is optional. All but one of the micrographs presented on this page do not have a bar, supplied magnification ratios are likely incorrect. The microscope has been used for scientific discovery. It has also linked to the arts since its invention in the 17th century. At first scientists used the microscope to view and draw objects not visible with the unaided eye, early adopters of the microscope, such as Robert Hooke and Antonie van Leeuwenhoek, were excellent illustrators
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Decidualization
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Decidualization is a process that results in significant changes to cells of the endometrium in preparation for, and during, pregnancy. This includes morphological and functional changes to endometrial stromal cells, the presence of white blood cells. The sum of these results in the endometrium changing into a structure called the decidua. In humans, the decidua is shed during the phase of birth. Decidualization plays an important role in promoting placenta formation between a mother and her fetus by mediating the invasiveness of trophoblast cells and it also triggers the production of cellular and molecular factors that result in structural changes, or remodeling, of maternal spiral arteries. Decidualization is required in some species where embryo implantation and trophoblast cell invasion of the endometrium occurs. This allows maternal blood to come into contact with the fetal chorion. However, decidualization-like reactions have also observed in some species that dont display hemochorial placentation. In humans, decidualization occurs after ovulation during the menstrual cycle, after implantation of the embryo, the decidua further develops to mediate the process of placentation. In the event no embryo is implanted, the endometrial lining is shed or, as is the case with species that follow the estrous cycle. After ovulation, the levels of progesterone initiate the molecular changes leading to decidualization. The process triggers an influx of decidual leukocytes along with morphological and functional changes of ESCs, the changes in the ESCs result in the endometrium developing a secretory lining that produces a variety of proteins, cytokines, and growth factors. These secreted factors will regulate the invasiveness of trophoblast cells that form the placental connection if an embryo implants into the decidua. One of the features of the decidua is the presence of large numbers of leukocytes that are mostly made up of specialized uterine natural killer cells. As the fetus consists of maternal and paternal DNA, the decidual leukocytes play a role in suppressing the immune response of the mother to prevent treating the fetus as genetically foreign. Outside of their functions, the uNK cells and dendritic cells also act as regulators of maternal spiral artery remodeling. ESCs are the tissue cells of the endometrium that are fibroblastic in appearance. However, decidualization causes them to swell up and adopt an epithelial cell-like appearance due to the accumulation of glycogen, furthermore, they begin secreting cytokines, growth factors, and proteins like IGFBP1 and prolactin, along with extracellular matrix proteins such as fibronectin and laminin
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H&E stain
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Hematoxylin and eosin stain or haematoxylin and eosin stain is one of the principal stains in histology. A combination of hematoxylin and eosin, it produces blues, violets, the staining method involves application of hemalum, a complex formed from aluminum ions and hematein. Hemalum colors nuclei of cells blue, the nuclear staining is followed by counterstaining with an aqueous or alcoholic solution of eosin Y, which colors eosinophilic structures in various shades of red, pink and orange. The staining of nuclei by hemalum is ordinarily due to binding of the complex to DNA. The mechanism is different from that of nuclear staining by basic dyes such as thionine or toluidine blue, staining by basic dyes occurs only from solutions that are less acidic than hemalum, and it is prevented by prior chemical or enzymatic extraction of nucleic acids. The eosinophilic structures are composed of intracellular or extracellular protein. The Lewy bodies and Mallory bodies are examples of eosinophilic structures, most of the cytoplasm is eosinophilic. Red blood cells are stained intensely red, the structures do not have to be acidic or basic to be called basophilic and eosinophilic, the terminology is based on the affinity of cellular components for the dyes. Other colors, e. g. yellow and brown, can be present in the sample, they are caused by intrinsic pigments, some structures do not stain well. Basal laminae need to be stained by PAS stain or some silver stains, reticular fibers also require silver stain. Hydrophobic structures also tend to clear, these are usually rich in fats, e. g. adipocytes, myelin around neuron axons. Hematoxylin is a blue or violet stain that is basic/positive. DNA/RNA in the nucleus, and RNA in ribosomes in the endoplasmic reticulum are both acidic because the phosphate backbones of nucleic acids are negatively charged. The negatively charged backbones form salts with basic dyes containing positive charges, therefore, dyes like hematoxylin will bind to DNA and RNA and stain them violet. Eosin is a red or pink stain that is Acidic / Negative and it binds to acidophilic substances such as positively charged amino acid side chains. Most proteins in the cytoplasm of cells are basic because they are positively charged due to the arginine and lysine amino acid residues. These form salts with acid dyes containing negative charges, like eosin, therefore, eosin binds to these amino acids/proteins and stains them pink. This includes cytoplasmic filaments in muscle cells, intracellular membranes, kiernan JA Histological and Histochemical Methods, Theory and Practice
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Stroma (tissue)
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Stroma is the part of a tissue or organ that has a connective and structural role. It consists of all the parts which do not conduct the functions of the organ, for example, connective tissue, blood vessels, nerves, ducts. The other part is the parenchyma, which is the cells that perform the function of the tissue or organ, there are multiple ways of classifying tissues, one way of classifying tissues is based on their functions and another is based on their cellular components. Stromal tissue falls into the class that functions in contributing to the body’s support, the cells that stroma tissues are composed of serve as a matrix in which the other cells are embedded. Stroma is made of various types of stromal cells, stromal tissue is primarily made of extracellular matrix containing connective tissue cells. Extracellular matrix is composed of ground substance - a porous, hydrated gel, made mainly from proteoglycan aggregates -. There are three types of commonly found within the stroma, collagen type I, elastic. Wandering cells - cells that migrate into the tissue from blood stream in response to a variety of stimuli, for example, fixed cells - cells that are permanent inhabitants of the tissue. Fibroblast - produce and secrete the organic parts of the ground substance, loose connective tissue - This type is mainly located under the epithelial membranes and glandular epithelium, attaching the epithelia to other tissues. It supports the blood vessels and nerves supplied to the epithelia, additionally, it serves as the main site of inflammatory response within the body. Dense irregular connective tissue - the function of type is binding at a high tensile strength between tissues to convert tension from one organ to another
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Connective tissue
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Connective tissue is one of the four types of biological tissue that supports, connects or separates different types of tissues and organs in the body. The other three types are epithelial, muscle, and nervous tissue, Connective tissue is found in between other tissues everywhere in the body, including the nervous system. In the central system, the three outer membranes that envelop the brain and spinal cord are composed of connective tissue. All connective tissue consists of three components, fibers, ground substance and cells. Blood and lymph lack the fiber component, all are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells, Connective tissue can be broadly subdivided into connective tissue proper, and special connective tissue. Connective tissue proper consists of connective tissue and dense connective tissue Special connective tissue consists of reticular connective tissue, adipose tissue, cartilage, bone. Other kinds of connective tissues include fibrous, elastic, and lymphoid connective tissues, new vascularised connective tissue that forms in the process of wound healing is termed granulation tissue. Fibroblasts are the responsible for the production of some CT. Type I collagen, is present in forms of connective tissue. Characteristics of CT, Cells are spread through an extracellular fluid, ground substance - A clear, colorless, and viscous fluid containing glycosaminoglycans and proteoglycans to fix the body water and the collagen fibers in the intercellular spaces. Ground substance slows the spread of pathogens, not all types of CT are fibrous. Examples of non-fibrous CT include adipose tissue and blood, adipose tissue gives mechanical cushioning to the body, among other functions. Although there is no dense collagen network in adipose tissue, groups of cells are kept together by collagen fibers. The matrix of blood is plasma, both the ground substance and proteins create the matrix for CT. Types of fibers, Connective tissue has a variety of functions that depend on the types of cells. They also allow organs to resist stretching and tearing forces, elastic fibers, made from elastin and fibrillin, also provide resistance to stretch forces. They are found in the walls of blood vessels and in certain ligaments
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Hormonal
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Hormones have diverse chemical structures, mainly of 3 classes, eicosanoids, steroids, and amino acid/protein derivatives. The glands that secrete hormones comprise the endocrine signaling system, the term hormone is sometimes extended to include chemicals produced by cells that affect the same cell or nearby cells. Hormones affect distant cells by binding to receptor proteins in the target cell resulting in a change in cell function. When a hormone binds to the receptor, it results in the activation of a signal transduction pathway, Hormone secretion may occur in many tissues. Endocrine glands are the example, but specialized cells in various other organs also secrete hormones. Hormone secretion occurs in response to specific biochemical signals from a range of regulatory systems. Upon secretion, certain hormones, including hormones and catecholamines, are water-soluble and are thus readily transported through the circulatory system. The endocrine system secretes hormones directly into the bloodstream typically into fenestrated capillaries, Hormones with paracrine function diffuse through the interstitial spaces to nearby target tissue. The reaction of the cells may then be recognized by the original hormone-producing cells. This is an example of a negative feedback loop. Hormone cells are typically of a cell type, residing within a particular endocrine gland, such as the thyroid gland, ovaries. Hormones exit their cell of origin via exocytosis or another means of membrane transport, the hierarchical model is an oversimplification of the hormonal signaling process. Different tissue types may also respond differently to the same hormonal signal, the rate of hormone biosynthesis and secretion is often regulated by a homeostatic negative feedback control mechanism. Such a mechanism depends on factors that influence the metabolism and excretion of hormones, thus, higher hormone concentration alone cannot trigger the negative feedback mechanism. Negative feedback must be triggered by overproduction of an effect of the hormone, for example, thyroid-stimulating hormone causes growth and increased activity of another endocrine gland, the thyroid, which increases output of thyroid hormones. To release active hormones quickly into the circulation, hormone biosynthetic cells may produce and these can then be quickly converted into their active hormone form in response to a particular stimulus. Eicosanoids are considered to act as local hormones and they are considered to be local because they possess specific effects on target cells close to their site of formation. They also have a rapid degradation cycle, making sure they do not reach distal sites within the body, most hormones initiate a cellular response by initially binding to either cell membrane associated or intracellular receptors
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Spiral artery
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Spiral arteries are small arteries which temporarily supply blood to endometrium of the uterus during the luteal phase of the menstrual cycle. In histology, identifying the presence of these arteries is one of the most useful techniques in identifying the phase of the cycle, the spiral arteries are converted for uteroplacental blood flow during pregnancy, involving, Loss of smooth muscle & elastic lamina from the vessel wall. 5-10 fold dilation at the mouth of the vessel, failure of the physiological conversion of the spiral arteries can cause a number of complications, including intrauterine growth restriction and pre-eclampsia
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Menstrual cycle
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The menstrual cycle is the regular natural change that occurs in the female reproductive system that makes pregnancy possible. The cycle is required for the production of ovocytes, and for the preparation of the uterus for pregnancy, up to 80% of women report having some symptoms during the one to two weeks prior to menstruation. Common symptoms include acne, tender breasts, bloating, feeling tired, irritability and these symptoms interfere with normal life and therefore qualify as premenstrual syndrome in 20 to 30% of women. In 3 to 8%, they are severe, the first period usually begins between twelve and fifteen years of age, a point in time known as menarche. They may occasionally start as early as eight, and this onset may still be normal, the average age of the first period is generally later in the developing world and earlier in developed world. The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women and 21 to 35 days in adults, menstruation stops occurring after menopause which usually occurs between 45 and 55 years of age. Bleeding usually lasts around 2 to 7 days, the menstrual cycle is governed by hormonal changes. These changes can be altered by using hormonal birth control to prevent pregnancy, each cycle can be divided into three phases based on events in the ovary or in the uterus. The ovarian cycle consists of the phase, ovulation, and luteal phase whereas the uterine cycle is divided into menstruation, proliferative phase. Stimulated by gradually increasing amounts of estrogen in the phase, discharges of blood flow stop. Follicles in the ovary begin developing under the influence of an interplay of hormones. Approximately mid-cycle, 24–36 hours after the luteinizing hormone surges, the dominant follicle releases an ovocyte, under the influence of progesterone, the uterine lining changes to prepare for potential implantation of an embryo to establish a pregnancy. If implantation does not occur within two weeks, the corpus luteum will involute, causing a sharp drop in levels of both progesterone and estrogen. The hormone drop causes the uterus to shed its lining in a process termed menstruation, menstruation also occurs in some other animals including shrews, bats, and other primates such as apes and monkeys. The average age of menarche is 12–15 and they may occasionally start as early as eight, and this onset may still be normal. This first period occurs later in the developing world than the developed world. The average age of menarche is approximately 12.5 years in the United States,12.7 in Canada,12.9 in the UK and 13.1 years in Iceland, factors such as genetics, diet and overall health can affect timing. The cessation of menstrual cycles at the end of a reproductive period is termed menopause
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Estrogen
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Estrogen or oestrogen is the primary female sex hormone as well as a medication. It is responsible for the development and regulation of the reproductive system. Estrogen may also refer to any substance, natural or synthetic, the estrane steroid estradiol is the most potent and prevalent endogenous estrogen, although several metabolites of estradiol also have estrogenic hormonal activity. They are one of three types of sex hormones, the others being androgens/anabolic steroids like testosterone and progestogens like progesterone, estrogens are synthesized in all vertebrates as well as some insects. Their presence in both vertebrates and insects suggests that sex hormones have an ancient evolutionary history. The three major naturally occurring forms of estrogen in women are estrone, estradiol, and estriol, another type of estrogen called estetrol is produced only during pregnancy. Quantitatively, estrogens circulate at lower levels than androgens in both men and women, while estrogen levels are significantly lower in males compared to females, estrogens nevertheless also have important physiological roles in males. Like all steroid hormones, estrogens readily diffuse across the cell membrane, once inside the cell, they bind to and activate estrogen receptors which in turn modulate the expression of many genes. Additionally, estrogens bind to and activate rapid-signaling membrane estrogen receptors, the three major naturally occurring estrogens in women are estrone, estradiol, and estriol. Estradiol is the predominant estrogen during reproductive years both in terms of serum levels as well as in terms of estrogenic activity. During menopause, estrone is the predominant circulating estrogen and during pregnancy estriol is the predominant circulating estrogen in terms of serum levels. Though estriol is the most plentiful of the three estrogens it is also the weakest, whereas estradiol is the strongest with a potency of approximately 80 times that of estriol. Thus, estradiol is the most important estrogen in non-pregnant females who are between the menarche and menopause stages of life, however, during pregnancy this role shifts to estriol, and in postmenopausal women estrone becomes the primary form of estrogen in the body. Another type of estrogen called estetrol is produced only during pregnancy, all of the different forms of estrogen are synthesized from androgens, specifically testosterone and androstenedione, by the enzyme aromatase. Estradiol, estrone, and estriol have all been approved as drugs and are used medically. Estetrol is currently under development for medical indications, but has not yet approved in any country. A variety of synthetic estrogen esters, such as estradiol valerate, estradiol cypionate, estradiol acetate, estradiol undecylate, polyestradiol phosphate, the aforementioned compounds behave as prodrugs to estradiol, and are longer-lasting in comparison. Esters of estrone and estriol also exist and are employed in clinical medicine, ethinylestradiol is a more potent synthetic analogue of estradiol that is used widely in hormonal contraceptives
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Corpus luteum
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The corpus luteum is a temporary endocrine structure in female ovaries that is involved in the production of relatively high levels of progesterone, moderate levels of estradiol and inhibin A. It is the remains of the follicle that has released a mature ovum during a previous ovulation. A new corpus luteum develops with each menstrual cycle, the corpus luteum develops from an ovarian follicle during the luteal phase of the menstrual cycle or oestrous cycle, following the release of a secondary oocyte from the follicle during ovulation. While the oocyte traverses the Fallopian tube into the uterus, the corpus luteum remains in the ovary. The corpus luteum is typically very large relative to the size of the ovary, in humans and its cells develop from the follicular cells surrounding the ovarian follicle. The follicular theca cells luteinize into small cells and follicular granulosa cells luteinize into large luteal cells forming the corpus luteum. Progesterone is synthesized from cholesterol by both the large and small luteal cells upon luteal maturation, cholesterol-LDL complexes bind to receptors on the plasma membrane of luteal cells and are internalized. Cholesterol is released and stored within the cell as cholesterol ester, LDL is recycled for further cholesterol transport. Large luteal cells produce more progesterone due to levels of protein kinase A activity within the cell. Small luteal cells have LH receptors that regulate PKA activity within the cell, PKA actively phosphorylates steroidogenic acute regulatory protein and translocator protein to transport cholesterol from the outer mitochondrial membrane to the inner mitochondrial membrane. The development of the corpus luteum is accompanied by an increase in the level of the steroidogenic enzyme P450scc that converts cholesterol to pregnenolone in the mitochondria, pregnenolone is then converted to progesterone that is secreted out of the cell and into the blood stream. The mitochondrial P450 system electron transport chain including adrenodoxin reductase and adrenodoxin has been shown to leak electrons leading to the formation of superoxide radical. Like the previous theca cells, the theca lutein cells lack the enzyme that is necessary to produce estrogen. Once the corpus luteum regresses the remnant is known as corpus albicans, the corpus luteum is essential for establishing and maintaining pregnancy in females. The corpus luteum secretes progesterone, which is a hormone responsible for the decidualization of the endometrium and maintenance. It also produces relaxin, a responsible for softening of the pubic symphysis which helps in parturition. If the egg is not fertilized, the corpus luteum stops secreting progesterone and it then degenerates into a corpus albicans, which is a mass of fibrous scar tissue. The uterine lining is expelled through the vagina, in an estrous cycle, the lining degenerates back to normal size
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Myometrium
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The myometrium is the middle layer of the uterine wall, consisting mainly of uterine smooth muscle cells, but also of supporting stromal and vascular tissue. Its main function is to induce uterine contractions, the myometrium is located between the endometrium, and the serosa or perimetrium. Myometrium has 3 layers, outer longitudinal smooth muscles, middle crisscrossing muscle fibres, middle crisscross fibres act as living ligature during involution of the uterus and prevent blood loss. The junctional layer appears to function like a muscle layer, capable of peristaltic and anti-peristaltic activity. The molecular structure of the muscle of myometrium is very similar to that of smooth muscle in other sites of the body. In uterine smooth muscle, there is approximately 6-fold more actin than myosin, a shift in the myosin expression of the uterine smooth muscle may be responsible for changes in the directions of uterine contractions during the menstrual cycle. As noted for the macrostructure of uterine smooth muscle, the junctional layer appears be capable of peristaltic and anti-peristaltic activity. The resting membrane potential of uterine smooth muscle has been recorded to be between -35 and -80 mV, subsequently, having K+ channels open to a higher degree than Na+ channels results in an overall efflux of positive ions, resulting in a negative potential. This resting potential undergoes rhythmic oscillations, which have been termed slow waves, K+ is the major ion responsible for such changes in ion flux, reflecting changes in various K+ channels. The excitation-contraction coupling of uterine smooth muscle is very similar to that of other smooth muscle in general. However, the factors for uterine smooth muscle differs from other types of smooth muscle. Removal of Ca2+ after contraction induces relaxation of the smooth muscle, after delivery the myometrium contracts to expel the placenta, and crisscrossing fibres of middle layer compress the blood vessels to minimize blood loss. A positive benefit to early breastfeeding is a stimulation of this reflex to reduce blood loss and facilitate a swift return to prepregnancy uterine. Lack of contraction at this stage is termed uterine atony, after pregnancy the uterus returns to its nonpregnant size by a process of myometrial involution. Benign neoplasms of the myometrium are very common, termed uterine leiomyomata or fibroids and their malignant version, leiomyosarcoma, is rare. Myometrium at the US National Library of Medicine Medical Subject Headings
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Follicular phase
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The follicular phase is the phase of the estrous cycle, during which follicles in the ovary mature. The main hormone controlling this stage is estradiol, follicle-stimulating hormone is secreted by the anterior pituitary gland. FSH secretion begins to rise in the last few days of the menstrual cycle. The rise in FSH levels recruits five to seven tertiary-stage ovarian follicles for entry into the menstrual cycle and these follicles, that have been growing for the better part of a year in a process known as folliculogenesis, compete with each other for dominance. FSH induces the proliferation of cells in the developing follicles. Under the influence of FSH, aromatase and p450 enzymes are activated and this increased level of estrogen stimulates production of gonadotropin-releasing hormone, which increases production of LH. LH induces androgen synthesis by thecal cells, stimulates proliferation, differentiation, throughout the entire follicular phase, rising estrogen levels in the blood stimulates growth of the endometrium and myometrium of the uterus. Two or three days before LH levels begin to increase, usually by day seven of the cycle, many endocrinologists believe that the estrogen secretion of the dominant follicle has increased to a level that GnRH production is suppressed, which lowers the levels of LH and FSH. This slowdown in LH and FSH production leads to the atresia of most of the recruited follicles, estrogen levels will continue to increase for several days. These high estrogen levels initiate the formation of a new layer of endometrium in the uterus, crypts in the cervix are also stimulated to produce fertile cervical mucus. This mucus reduces the acidity of the vagina, creating a more hospitable environment for sperm and it also has a characteristic texture that helps guide sperm through the cervix and to the fallopian tubes, where they wait for ovulation. In addition, basal body temperature may lower slightly under the influence of estrogen levels. Estrogen levels are highest right before the LH surge begins, the short-term drop in steroid hormones between the beginning of the LH surge and the event of ovulation may cause mid-cycle spotting or bleeding. Under the influence of the preovulatory LH surge, the first meiotic division of the oocytes is completed, the surge also initiates luteinization of thecal and granulosa cells. Ovulation normally occurs 30 hours after the beginning of the LH surge, the time from recruitment of tertiary stage follicles to ovulation, is normally about two weeks, comprising days 1-14 of an idealized 28-day menstrual cycle. However, it is common for the phase to last much longer. In this case, more tertiary stage follicles are usually recruited, fertility awareness sources may refer to multiple waves of follicular development as a split peak because of the characteristic pattern of cervical mucus changes that is sometimes observed
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Luteal phase
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The luteal phase is the latter phase of the menstrual cycle or the earlier phase of the estrous cycle. It begins with the formation of the corpus luteum and ends in either pregnancy or luteolysis, the main hormone associated with this stage is progesterone, which is significantly higher during the luteal phase than other phases of the cycle. The opposite of the phase, the rest of the two weeks, is called the follicular phase. After ovulation, the pituitary hormones FSH and LH cause the remaining parts of the dominant follicle to transform into the corpus luteum. It continues to grow for some time after ovulation and produces significant amounts of hormones, particularly progesterone, and, to a lesser extent, oestrogen. Several days after ovulation, the amount of estrogen produced by the corpus luteum may cause one or two days of fertile cervical mucus, lower basal body temperatures, or both. This is known as a secondary oestrogen surge, the hormones produced by the corpus luteum also suppress production of the FSH and LH that the corpus luteum needs to maintain itself. With continued low levels of FSH and LH, the corpus luteum will atrophy, the death of the corpus luteum results in falling levels of progesterone and oestrogen. These falling levels of ovarian hormones cause increased levels of FSH, continued drops in levels of oestrogen and progesterone trigger the end of the luteal phase, menstruation and the beginning of the next cycle. The human luteal phase lasts between ten and sixteen days, the average being fourteen days, luteal phases of less than twelve days may make it more difficult to achieve pregnancy. While luteal phase length varies significantly from woman to woman, for the woman the length will be fairly consistent from cycle to cycle. Because the hormone is unique to the embryo, most pregnancy tests look for the presence of hCG, if implantation occurs, the corpus luteum will continue to produce progesterone for eight to twelve weeks, after which the placenta takes over this function. Luteal phase defect, or luteal insufficiency, occurs when the phase is shorter than normal, progesterone levels during the luteal phase are below normal. LPD is believed to interfere with the implantation of embryos. The lactational amenorrhea method of control works primarily by preventing ovulation. There is unruptured luteinized follicle syndrome, short luteal phases that are, for example, nine days long, some people have seen normalization with a high dose of vitamin B6. ULFS can be treated by a dose of hCG at ovulation. LPD can be diagnosed by ultrasound, day 21 progesterone tests, and observing the length of luteal phase
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Bioinformatics
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Bioinformatics /ˌbaɪ. oʊˌɪnfərˈmætɪks/ is an interdisciplinary field that develops methods and software tools for understanding biological data. As an interdisciplinary field of science, bioinformatics combines computer science, statistics, mathematics, Bioinformatics has been used for in silico analyses of biological queries using mathematical and statistical techniques. Common uses of bioinformatics include the identification of genes and nucleotides. Often, such identification is made with the aim of understanding the genetic basis of disease, unique adaptations, desirable properties. In a less formal way, bioinformatics also tries to understand the principles within nucleic acid and protein sequences. Bioinformatics has become an important part of areas of biology. In experimental molecular biology, bioinformatics techniques such as image and signal processing allow extraction of useful results from large amounts of raw data, in the field of genetics and genomics, it aids in sequencing and annotating genomes and their observed mutations. It plays a role in the mining of biological literature. It also plays a role in the analysis of gene and protein expression and regulation, Bioinformatics tools aid in the comparison of genetic and genomic data and more generally in the understanding of evolutionary aspects of molecular biology. At a more level, it helps analyze and catalogue the biological pathways. In structural biology, it aids in the simulation and modeling of DNA, RNA, historically, the term bioinformatics did not mean what it means today. Paulien Hogeweg and Ben Hesper coined it in 1970 to refer to the study of processes in biotic systems. This definition placed bioinformatics as a parallel to biophysics or biochemistry. Computers became essential in molecular biology when protein sequences became available after Frederick Sanger determined the sequence of insulin in the early 1950s, comparing multiple sequences manually turned out to be impractical. A pioneer in the field was Margaret Oakley Dayhoff, who has been hailed by David Lipman, director of the National Center for Biotechnology Information, Dayhoff compiled one of the first protein sequence databases, initially published as books and pioneered methods of sequence alignment and molecular evolution. To study how normal cellular activities are altered in different disease states, therefore, the field of bioinformatics has evolved such that the most pressing task now involves the analysis and interpretation of various types of data. This includes nucleotide and amino acid sequences, protein domains, the actual process of analyzing and interpreting data is referred to as computational biology. For example, there are methods to locate a gene within a sequence, to predict protein structure and/or function, the primary goal of bioinformatics is to increase the understanding of biological processes
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Progesterone receptor
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The progesterone receptor, also known as NR3C3 or nuclear receptor subfamily 3, group C, member 3, is a protein found inside cells. It is activated by the hormone progesterone. In humans, PR is encoded by a single PGR gene residing on chromosome 11q22, a third, lesser-known isoform, the PRC, also exists. Progesterone is necessary to induce the progesterone receptors, when no binding hormone is present the carboxyl terminal inhibits transcription. Binding to a hormone induces a change that removes the inhibitory action. Progesterone antagonists prevent the structural reconfiguration, after progesterone binds to the receptor, restructuring with dimerization follows and the complex enters the nucleus and binds to DNA. There transcription takes place, resulting in formation of messenger RNA that is translated by ribosomes to produce specific proteins. In common with other receptors, the progesterone receptor has a N-terminal regulatory domain, a DNA binding domain, a hinge section. A special transcription activation function, called TAF-3, is present in the progesterone receptor-B and this segment is not present in the receptor-A. These results suggest that in the uterus, the PR-A isoform is necessary to oppose estrogen-induced proliferation as well as PR-B-dependent proliferation, six variable sites, including four polymorphisms and five common haplotypes have been identified in the human PR gene. One promoter region polymorphism, +331G/A, creates a transcription start site. Biochemical assays showed that the +331G/A polymorphism increases transcription of the PR gene, several studies have now shown no association between progesterone receptor gene +331G/A polymorphisms and breast or endometrial cancers. However, these follow-up studies lacked the size and statistical power to make any definitive conclusions. It is currently unknown if any polymorphisms in this receptor are of significance to cancer. Knockout mice of the PR have been found to have severely impaired lobuloalveolar development of the glands as well as delayed. Progesterone receptor antagonists work as antiprogestins, selective progesterone receptor modulators may also have more or less antagonist activity. Additional PR antagonists include, onapristone, lonaprisan, APR19, EC304, WAY-255348, ORG31710, asoprisnil, telapristone, progesterone receptor has been shown to interact with, KLF9, Nuclear receptor co-repressor 2, and UBE3A
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Thyrotropin-releasing hormone
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It is a tropic, tripeptidal hormone. TRH has been used clinically for the treatment of spinocerebellar degeneration and its pharmaceutical form is called protirelin. TRH is produced by the globe in medial neurons of the paraventricular nucleus, at the beginning, it is synthesized as a 242-amino acid precursor polypeptide that contains 6 copies of the sequence -Gln-His-Pro-Gly-, flanked by Lys-Arg or Arg-Arg sequences. To produce the form, a series of enzymes are required. First, a protease cleaves to the C-terminal side of the flanking Lys-Arg or Arg-Arg, second, a carboxypeptidase removes the Lys/Arg residues leaving Gly as the C-terminal residue. Then, this Gly is converted into an amide residue by a series of enzymes known as peptidylglycine-alpha-amidating monooxygenase. Concurrently with these steps, the N-terminal Gln is converted into pyroglutamate. These multiple steps produce 6 copies of the mature TRH molecule per precursor molecule for human TRH, TRH can also be detected in other areas of the body including the gastrointestinal system and pancreatic islets, as well as in the brain. The sequence of TRH was first determined, and the hormone synthesized, by Roger Guillemin, both parties insisted their labs determined the sequence first, Schally first suggested the possibility in 1966, but abandoned it after Guillemin proposed TRH was not actually a peptide. Guillemins chemist began concurring with these results in 1969, as NIH threatened to cut off funding for the project, Schally and Guillemin shared the 1977 Nobel Prize in Medicine for their discoveries concerning the peptide hormone production of the brain. News accounts of their work often focused on their competition and use of a very large amount of sheep. Its molecular weight is 359.5 Da and its logp octanol/water is -2.46 TRH is used clinically by intravenous injection to test the response of the anterior pituitary gland, this procedure is known as a TRH test. This is done as diagnostic test of thyroid disorders such as secondary hypothyroidism, TRH has anti-depressant and anti-suicidal properties, and in 2012 the U. S. Army awarded a research grant to develop a TRH nasal spray in order to prevent suicide amongst its ranks. Side effects after intravenous TRH administration are minimal, nausea, flushing, urinary urgency, and mild rise in blood pressure have been reported. After intrathecal administration, shaking, sweating, shivering, restlessness, TRH belongs to a family of several thyrotropin-releasing hormones
32.
HOXA11
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Homeobox protein Hox-A11 is a protein that in humans is encoded by the HOXA11 gene. In vertebrates, the genes encoding the class of transcription factors called homeobox genes are found in clusters named A, B, C, expression of these proteins is spatially and temporally regulated during embryonic development. This gene is part of the A cluster on chromosome 7 and encodes a DNA-binding transcription factor which may regulate gene expression, morphogenesis and this gene is involved in the regulation of uterine development and is required for female fertility. Mutations in this gene can cause radioulnar synostosis with amegakaryocytic thrombocytopenia
33.
Estrogen receptor alpha
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Estrogen receptor alpha, also known as NR3A1, is one of two main types of estrogen receptor, a nuclear receptor that is activated by the sex hormone estrogen. In humans, ERα is encoded by the gene ESR1, the estrogen receptor is a ligand-activated transcription factor composed of several domains important for hormone binding, DNA binding, and activation of transcription. Alternative splicing results in several ESR1 mRNA transcripts, which differ primarily in their 5-prime untranslated regions, the translated receptors show less variability. The clinical presentation in a male was reported to lack of epiphyseal closure, tall stature, osteoporosis. Both individuals were completely insensitive to exogenous estrogen treatment, even high doses
34.
Breast
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The breast is one of two prominences located on the upper ventral region of the torso of female primates. In females, it serves as the mammary gland, which produces and secretes milk, both females and males develop breasts from the same embryological tissues. At puberty, estrogens, in conjunction with growth hormone, cause breast development, the breasts of females are typically far more prominent than those of males. Subcutaneous fat covers and envelops a network of ducts that converge on the nipple, at the ends of the ducts are lobules, or clusters of alveoli, where milk is produced and stored in response to hormonal signals. Upon childbirth, the alveoli are stimulated to produce and secrete milk for infants, along with their function in feeding infants, female breasts have social and sexual characteristics. Breasts have been featured in ancient and modern sculpture, art. Female breasts can figure prominently in a perception of her body image. A number of Western cultures associate breasts with sexuality and tend to regard bare breasts in public as immodest or indecent, Breasts and especially the nipples are an erogenous zone on women. The English word breast derives from the Old English word brēost from Proto-Germanic breustam, the breast spelling conforms to the Scottish and North English dialectal pronunciations. The Merriam-Webster Dictionary states that Middle English brest, from Old English brēost, Old Irish brú, Russian bryukho, the first known usage of the term was before the 12th century. A large number of terms for breasts are used in English. Some vulgar slang expressions may be considered to be derogatory or sexist to women, at the front of the chest, the breast tissue can extend from the clavicle to the middle of the sternum. At the sides of the chest, the breast tissue can extend into the axilla, as a mammary gland, the breast is composed of differing layers of tissue, predominantly two types, adipose tissue, and glandular tissue, which affects the lactation functions of the breasts. Morphologically the breast is a cone, with the base at the chest wall and the apex at the nipple, the superficial tissue layer is separated from the skin by 0. 5–2.5 cm of subcutaneous fat. The suspensory Coopers ligaments are fibrous-tissue prolongations that radiate from the superficial fascia to the skin envelope, the female adult breast contains 14–18 irregular lactiferous lobes that converge at the nipple. Milk exits the breast through the nipple, which is surrounded by an area of skin called the areola. The size of the areola can vary widely among women, the areola contains modified sweat glands known as Montgomerys glands. These glands secrete oily fluid that lubricate and protect the nipple during breastfeeding, volatile compounds in these secretions may also serve as an olfactory stimulus for the newborns appetite
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. PMID 22057551.
