1.
RAE Larynx
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The Royal Aircraft Establishment Larynx was an early British pilotless aircraft, to be used as a guided anti-ship weapon. Started in September 1925, it was a cruise missile guided by an autopilot. A small monoplane powered by a 200 hp Armstrong Siddeley Lynx IV engine, it had a top speed of 200 mph, faster than contemporary fighters. It used autopilot principles developed by Professor Archibald Low and already used in the Ruston Proctor AT, launched from cordite-powered catapult fitted to the S class destroyer HMS Stronghold. Thought to have flown 100 miles and was then lost,112 mile flight, hit five miles from target. Two more launches in September and October 1928 from HMS Thanet, launched from land, one overflew target and other was successful
2.
Anatomical terms of location
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Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. All vertebrates have the basic body plan – they are strictly bilaterally symmetrical in early embryonic stages. That is, they have left and right halves if divided down the centre. For these reasons, the directional terms can be considered to be those used in vertebrates. By extension, the terms are used for many other organisms as well. While these terms are standardized within specific fields of biology, there are unavoidable, sometimes dramatic, for example, differences in terminology remain a problem that, to some extent, still separates the terminology of human anatomy from that used in the study of various other zoological categories. The vertebrates and Craniata share a heritage and common structure. To avoid ambiguities this terminology is based on the anatomy of each animal in a standard way, for humans, one type of vertebrate, anatomical terms may differ from other forms of vertebrates. Thus what is on top of a human is the head, whereas the top of a dog may be its back, for example, many species are not even bilaterally symmetrical. In these species, terminology depends on their type of symmetry, all descriptions are with respect to the organism in its standard anatomical position, even when the organism in question has appendages in another position. This helps avoid confusion in terminology when referring to the organism in different postures. In humans, this refers to the body in a position with arms at the side. While the universal vertebrate terminology used in medicine would work in human medicine. Many anatomical terms can be combined, either to indicate a position in two axes simultaneously or to indicate the direction of a movement relative to the body, for example, anterolateral indicates a position that is both anterior and lateral to the body axis. There is no limit to the contexts in which terms may be modified to qualify each other in such combinations. Generally the modifier term is truncated and an o or an i is added in prefixing it to the qualified term, where desirable three or more terms may be agglutinated or concatenated, as in anteriodorsolateral. Such terms sometimes used to be hyphenated, but the tendency is to omit the hyphen. There is however little basis for any rule to interfere with choice of convenience in such usage
3.
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
4.
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
5.
Organ (anatomy)
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In biology, an organ or viscus is a collection of tissues joined in a structural unit to serve a common function. In anatomy, a viscus is an organ, and viscera is the plural form. Organs are composed of main tissue, parenchyma, and sporadic tissues, the main tissue is that which is unique for the specific organ, such as the myocardium, the main tissue of the heart, while sporadic tissues include the nerves, blood vessels, and connective tissues. The main tissues that make up an organ tend to have common embryologic origins, functionally related organs often cooperate to form whole organ systems. Organs exist in all biological organisms, in particular they are not restricted to animals. In single-cell organisms like bacteria, the analogue of an organ is called organelle. A hollow organ is an organ that forms a hollow tube or pouch, such as the stomach or intestine, or that includes a cavity. Two or more organs working together in the execution of a specific body function form an organ system, the functions of organ systems often share significant overlap. For instance, the nervous and endocrine system both operate via an organ, the hypothalamus. For this reason, the two systems are combined and studied as the neuroendocrine system, the same is true for the musculoskeletal system because of the relationship between the muscular and skeletal systems. Mammals such as humans have a variety of organ systems and these specific systems are also widely studied in human anatomy. Cardiovascular system, pumping and channeling blood to and from the body and lungs with heart, digestive system, digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, colon, rectum and anus. Excretory system, kidneys, ureters, bladder and urethra involved in balance, electrolyte balance. Integumentary system, skin, hair and nails, nervous system, collecting, transferring and processing information with brain, spinal cord and nerves. Reproductive system, the sex organs, such as ovaries, fallopian tubes, uterus, vulva, vagina, testes, vas deferens, seminal vesicles, prostate, respiratory system, the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs and diaphragm. Skeletal system, structural support and protection with bones, cartilage, ligaments, the organ level of organisation in animals can be first detected in flatworms and the more advanced phyla. The less-advanced taxa do not show consolidation of their tissues into organs, the study of plant organs is referred to as plant morphology, rather than anatomy, as in animal systems. Organs of plants can be divided into vegetative and reproductive, vegetative plant organs are roots, stems, and leaves
6.
Neck
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The neck is the part of the body, on many vertebrates, that separates the head from the torso or trunk. It contains blood vessels and nerves that supply structures in the head to the body. These in humans include part of the esophagus, the larynx, trachea, and thyroid gland, major blood vessels including the arteries and jugular veins. In anatomy, the neck is called by its Latin names, cervix or collum, although when used alone, in context, the word cervix more often refers to the uterine cervix. Thus the adjective cervical may refer either to the neck or to the uterine cervix, the neck contains vessels that links structures in the head to the body. In humans these structures include part of the esophagus, larynx, trachea, thyroid and parathyroid glands, lymph nodes, major blood vessels present include the carotid arteries and the jugular veins. Cervical lymph nodes surround the blood vessels, the thyroid gland and parathyroid gland are endocrine glands involved in the regulation of cellular metabolism and growth, and blood calcium levels. The shape of the neck in humans is formed from the part of the vertebral column at the back. Around these sit soft tissues, including muscles, and between and around these sit the other structures mentioned above, muscles of the neck attach to the base of the skull, the hyoid bone, the clavicles and the sternum. The large platysma, sternocleidomastoid muscles contribute to the shape at the front, a number of other muscles attach to and stem from the hyoid bone, facilitating speech and playing a role in swallowing. Sensation to the front areas of the neck comes from the roots of nerves C2-4, the cervical region of the human spine is made up of seven cervical vertebrae referred to as C-1 to C-7, with cartilaginous discs between each vertebral body. The spinal cord sits within the part of the vertebral column. The spinal column carries nerves that carry sensory and motor information from the brain down to the rest of the body, from top to bottom the cervical spine is gently curved in convex-forward fashion. In addition to coming from and within the human spine. In the middle line below the chin can be felt the body of the bone, just below which is the prominence of the thyroid cartilage called Adams apple. Still lower the cricoid cartilage is easily felt, while between this and the notch the trachea and isthmus of the thyroid gland may be made out. At the side the outline of the muscle is the most striking mark. The upper part of the former contains the submaxillary gland also known as the submandibular glands, the line of the common and the external carotid arteries may be marked by joining the sterno-clavicular articulation to the angle of the jaw
7.
Tetrapod
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The superclass Tetrapoda contains the four-limbed vertebrates known as tetrapods, it includes living and extinct amphibians, reptiles and mammals, as well as earlier extinct groups. The first tetrapods appeared by the late Devonian,367, the first tetrapods were primarily aquatic. Their descendants drove most amphibians to extinction as they began to dominate, the amniotes include the tetrapods that further evolved for flight—such as birds from among the dinosaurs, and bats from among the mammals. The change from a plan for breathing and navigating in water to a body plan enabling the animal to move on land is one of the most profound evolutionary changes known. It is also becoming increasingly well-understood as a result of more transitional fossil finds, many tetrapods have returned to partially aquatic or fully aquatic lives throughout the history of the group. Tetrapods can be defined in cladistics as the nearest common ancestor of all living amphibians and all living amniotes, the group so defined is the crown group, or crown tetrapods. The term tetrapodomorph is used for the definition, any animal that is more closely related to living amphibians, reptiles, birds. The group so defined is known as the total group. Stegocephalia is a larger group equivalent to some uses of the word tetrapod. Batrachomorphs are all sharing a more recent common ancestry with living amphibians than with living amniotes. Reptiliomorphs are all sharing a more recent common ancestry with living amniotes than with living amphibians. Tetrapoda includes four classes, amphibians, reptiles, mammals, however, that diversification process was interrupted at least a few times by major biological crises, such as the Permian–Triassic extinction event, which at least affected amniotes. As biodiversity has grown, so has the number of niches that tetrapods have occupied, the first tetrapods were aquatic and fed primarily on fish. Today, the Earth supports a diversity of tetrapods that live in many habitats. Tetrapods evolved from early bony fishes, specifically from the branch of lobe-finned fishes. The first tetrapods probably evolved in the Emsian stage of the Early Devonian from Tetrapodomorph fish living in water environments. The very earliest tetrapods would have been similar to Acanthostega, with legs and lungs as well as gills. The earliest tetrapods inhabited saltwater, brackish-water, and freshwater environments and these traits were shared with many early lobed-finned fishes
8.
Pitch (music)
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Pitch can be determined only in sounds that have a frequency that is clear and stable enough to distinguish from noise. Pitch is a major attribute of musical tones, along with duration, loudness. Pitch may be quantified as a frequency, but pitch is not a purely objective physical property, Pitch is an auditory sensation in which a listener assigns musical tones to relative positions on a musical scale based primarily on their perception of the frequency of vibration. Pitch is closely related to frequency, but the two are not equivalent, frequency is an objective, scientific attribute that can be measured. Pitch is each persons subjective perception of a wave, which cannot be directly measured. However, this not necessarily mean that most people wont agree on which notes are higher and lower. Sound waves themselves do not have pitch, but their oscillations can be measured to obtain a frequency and it takes a sentient mind to map the internal quality of pitch. However, pitches are usually associated with, and thus quantified as frequencies in cycles per second, or hertz, by comparing sounds with pure tones, Complex and aperiodic sound waves can often be assigned a pitch by this method. According to the American National Standards Institute, pitch is the attribute of sound according to which sounds can be ordered on a scale from low to high. That is, high pitch means very rapid oscillation, and low pitch corresponds to slower oscillation, despite that, the idiom relating vertical height to sound pitch is shared by most languages. At least in English, it is just one of many deep conceptual metaphors that involve up/down, the exact etymological history of the musical sense of high and low pitch is still unclear. There is evidence that humans do actually perceive that the source of a sound is slightly higher or lower in vertical space when the frequency is increased or reduced. The pitch of tones can be ambiguous, meaning that two or more different pitches can be perceived, depending upon the observer. In a situation like this, the percept at 200 Hz is commonly referred to as the missing fundamental, Pitch depends to a lesser degree on the sound pressure level of the tone, especially at frequencies below 1,000 Hz and above 2,000 Hz. The pitch of lower tones gets lower as sound pressure increases, for instance, a tone of 200 Hz that is very loud seems one semitone lower in pitch than if it is just barely audible. Above 2,000 Hz, the pitch gets higher as the sound gets louder, theories of pitch perception try to explain how the physical sound and specific physiology of the auditory system work together to yield the experience of pitch. In general, pitch perception theories can be divided into place coding, place theory holds that the perception of pitch is determined by the place of maximum excitation on the basilar membrane. However, a purely place-based theory cannot account for the accuracy of pitch perception in the low, temporal theories offer an alternative that appeals to the temporal structure of action potentials, mostly the phase-locking and mode-locking of action potentials to frequencies in a stimulus
9.
Sound pressure
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Sound pressure or acoustic pressure is the local pressure deviation from the ambient atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, the SI unit of sound pressure is the pascal. A sound wave in a medium causes a deviation in the local ambient pressure. Sound pressure, denoted p, is defined by p t o t a l = p s t a t + p, in a sound wave, the complementary variable to sound pressure is the particle velocity. Together they determine the intensity of the wave. Sound intensity, denoted I and measured in W·m−2 in SI units, is defined by I = p v. Consequently, the amplitude of the displacement is related to that of the acoustic velocity. This relationship is an inverse-proportional law, if the sound pressure p1 is measured at a distance r1 from the centre of the sphere, the sound pressure p2 at another position r2 can be calculated, p 2 = r 1 r 2 p 1. The inverse-proportional law for sound pressure comes from the law for sound intensity. Indeed, I = p v = p ∝ p 2, the sound pressure may vary in direction from the centre of the sphere as well, so measurements at different angles may be necessary, depending on the situation. An obvious example of a sound source whose spherical sound wave varies in level in different directions is a bullhorn, Sound pressure level or acoustic pressure level is a logarithmic measure of the effective pressure of a sound relative to a reference value. The commonly used reference sound pressure in air is p 0 =20 μ P a, which is often considered as the threshold of human hearing. The proper notations for sound pressure level using this reference are Lp/ or Lp, most sound level measurements will be made relative to this reference, meaning 1 Pa will equal an SPL of 94 dB. In other media, such as underwater, a level of 1 μPa is used. These references are defined in ANSI S1. 1-1994, the lower limit of audibility is defined as SPL of 0 dB, but the upper limit is not as clearly defined. Ears detect changes in sound pressure, human hearing does not have a flat spectral sensitivity relative to frequency versus amplitude. Humans do not perceive low- and high-frequency sounds as well as they perceive sounds between 3,000 and 4,000 Hz, as shown in the equal-loudness contour. Because the frequency response of human hearing changes with amplitude, three weightings have been established for measuring pressure, A, B and C. A-weighting applies to sound pressures levels up to 55 dB, B-weighting applies to sound levels between 55 dB and 85 dB, and C-weighting is for measuring sound pressure levels above 85 dB
10.
Phonation
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The term phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration and this is the definition used among those who study laryngeal anatomy and physiology and speech production in general. Voiceless and supra-glottal phonations are included under this definition, the phonatory process, or voicing, occurs when air is expelled from the lungs through the glottis, creating a pressure drop across the larynx. When this drop becomes sufficiently large, the vocal folds start to oscillate, the minimum pressure drop required to achieve phonation is called the phonation threshold pressure, and for humans with normal vocal folds, it is approximately 2–3 cm H2O. The motion of the vocal folds during oscillation is mostly lateral, however, there is almost no motion along the length of the vocal folds. The oscillation of the vocal folds serves to modulate the pressure and flow of the air through the larynx, the sound that the larynx produces is a harmonic series. In other words, it consists of a fundamental tone accompanied by harmonic overtones, in linguistics, a phone is called voiceless if there is no phonation during its occurrence. In speech, voiceless phones are associated with folds that are elongated, highly tensed. Fundamental frequency, the main acoustic cue for the percept pitch, large scale changes are accomplished by increasing the tension in the vocal folds through contraction of the cricothyroid muscle. Variation in fundamental frequency is used linguistically to produce intonation and tone, There are currently two main theories as to how vibration of the vocal folds is initiated, the myoelastic theory and the aerodynamic theory. These two theories are not in contention with one another and it is possible that both theories are true and operating simultaneously to initiate and maintain vibration. A third theory, the theory, was in considerable vogue in the 1950s. Pressure builds up again until the cords are pushed apart. The rate at which the open and close—the number of cycles per second—determines the pitch of the phonation. The aerodynamic theory is based on the Bernoulli energy law in fluids, the push occurs during glottal opening, when the glottis is convergent, whereas the pull occurs during glottal closing, when the glottis is divergent. Such an effect causes a transfer of energy from the airflow to the fold tissues which overcomes losses by dissipation. The amount of pressure needed to begin phonation is defined by Titze as the oscillation threshold pressure. During glottal closure, the air flow is cut off until breath pressure pushes the folds apart and this theory states that the frequency of the vocal fold vibration is determined by the chronaxie of the recurrent nerve, and not by breath pressure or muscular tension
11.
Ancient Greek
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Ancient Greek includes the forms of Greek used in ancient Greece and the ancient world from around the 9th century BC to the 6th century AD. It is often divided into the Archaic period, Classical period. It is antedated in the second millennium BC by Mycenaean Greek, the language of the Hellenistic phase is known as Koine. Koine is regarded as a historical stage of its own, although in its earliest form it closely resembled Attic Greek. Prior to the Koine period, Greek of the classic and earlier periods included several regional dialects, Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical phases of the language, Ancient Greek was a pluricentric language, divided into many dialects. The main dialect groups are Attic and Ionic, Aeolic, Arcadocypriot, some dialects are found in standardized literary forms used in literature, while others are attested only in inscriptions. There are also several historical forms, homeric Greek is a literary form of Archaic Greek used in the epic poems, the Iliad and Odyssey, and in later poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic, the origins, early form and development of the Hellenic language family are not well understood because of a lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period and they have the same general outline, but differ in some of the detail. The invasion would not be Dorian unless the invaders had some relationship to the historical Dorians. The invasion is known to have displaced population to the later Attic-Ionic regions, the Greeks of this period believed there were three major divisions of all Greek people—Dorians, Aeolians, and Ionians, each with their own defining and distinctive dialects. Often non-west is called East Greek, Arcadocypriot apparently descended more closely from the Mycenaean Greek of the Bronze Age. Boeotian had come under a strong Northwest Greek influence, and can in some respects be considered a transitional dialect, thessalian likewise had come under Northwest Greek influence, though to a lesser degree. Most of the dialect sub-groups listed above had further subdivisions, generally equivalent to a city-state and its surrounding territory, Doric notably had several intermediate divisions as well, into Island Doric, Southern Peloponnesus Doric, and Northern Peloponnesus Doric. The Lesbian dialect was Aeolic Greek and this dialect slowly replaced most of the older dialects, although Doric dialect has survived in the Tsakonian language, which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek, by about the 6th century AD, the Koine had slowly metamorphosized into Medieval Greek
12.
Vertebra
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The basic configuration of a vertebra varies, the large part is the body, and the central part is the centrum. The upper and lower surfaces of the vertebra body give attachment to the intervertebral discs, the posterior part of a vertebra forms a vertebral arch, in eleven parts, consisting of two pedicles, two laminae, and seven processes. The laminae give attachment to the ligamenta flava, there are vertebral notches formed from the shape of the pedicles, which form the intervertebral foramina when the vertebrae articulate. These foramina are the entry and exit conducts for the spinal nerves, the body of the vertebra and the vertebral arch form the vertebral foramen, the larger, central opening that accommodates the spinal canal, which encloses and protects the spinal cord. Vertebrae articulate with other to give strength and flexibility to the spinal column. Structurally, vertebrae are essentially alike across the species, with the greatest difference seen between an aquatic animal and other vertebrate animals. As such, vertebrates take their name from the vertebrae that compose the vertebral column, each vertebra is an irregular bone. The size of the vertebrae varies according to placement in the column, spinal loading, posture. Along the length of the spine the vertebrae change to different needs related to stress. Every vertebra has a body, which consists of a large anterior middle portion called the centrum, the body is composed of cancellous bone, which is the spongy type of osseous tissue, whose micro-anatomy has been specifically studied within the pedicle bones. This cancellous bone is in turn, covered by a coating of cortical bone. The vertebral arch and processes have thicker coverings of cortical bone, the upper and lower surfaces of the body of the vertebra are flattened and rough in order to give attachment to the intervertebral discs. These surfaces are the vertebral endplates which are in contact with the intervertebral discs. The endplates are formed from a layer of the cancellous bone of the vertebral body. The endplates function to contain the adjacent discs, to spread the applied loads. They also act as an interface for the exchange of water. The vertebral arch is formed by pedicles and laminae, two pedicles extend from the sides of the vertebral body to join the body to the arch. The pedicles are short thick processes that extend, one each side, posteriorly, from the junctions of the posteriolateral surfaces of the centrum
13.
Cartilage
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It is not as hard and rigid as bone, but it is stiffer and less flexible than muscle. Because of its rigidity, cartilage often serves the purpose of holding tubes open in the body, cartilage is classified in three types, elastic cartilage, hyaline cartilage and fibrocartilage, which differ in relative amounts of collagen and proteoglycan. Cartilage does not contain blood vessels or nerves, nutrition is supplied to the chondrocytes by diffusion. The compression of the cartilage or flexion of the elastic cartilage generates fluid flow. Compared to other tissues, cartilage has a very slow turnover of its extracellular matrix. In embryogenesis, the system is derived from the mesoderm germ layer. Following the initial chondrification that occurs during embryogenesis, cartilage growth consists mostly of the maturing of immature cartilage to a mature state. The division of cells within cartilage occurs very slowly, and thus growth in cartilage is not based on an increase in size or mass of the cartilage itself. The articular cartilage function is dependent on the composition of the extracellular matrix. The ECM consists mainly of proteoglycan and collagens, the main proteoglycan in cartilage is aggrecan, which, as its name suggests, forms large aggregates with hyaluronan. These aggregates are negatively charged and hold water in the tissue, the collagen, mostly collagen type II, constrains the proteoglycans. The ECM responds to tensile and compressive forces that are experienced by the cartilage, cartilage growth thus refers to the matrix deposition, but can also refer to both the growth and remodeling of the extracellular matrix. Due to the stress on the patellofemoral joint during resisted knee flexion. The mechanical properties of articular cartilage in load bearing joints such as knee and hip have been studied extensively at macro, micro and these mechanical properties include the response of cartilage in frictional, compressive, shear and tensile loading. Cartilage is resilient and displays viscoelastic properties, lubricin, a glycoprotein abundant in cartilage and synovial fluid, plays a major role in bio-lubrication and wear protection of cartilage. Cartilage has limited capabilities, Because chondrocytes are bound in lacunae. Therefore, cartilage damage is difficult to heal, also, because hyaline cartilage does not have a blood supply, the deposition of new matrix is slow. Damaged hyaline cartilage is replaced by fibrocartilage scar tissue
14.
Corniculate cartilages
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They are situated in the posterior parts of the aryepiglottic folds of mucous membrane, and are sometimes fused with the arytenoid cartilages. It is named by Giovanni Domenico Santorini, the word Corniculate has a Latin root cornu. The projections of Corniculate cartilage look like horns hence the name and this article incorporates text in the public domain from the 20th edition of Grays Anatomy Atlas image, rsa3p8 at the University of Michigan Health System
15.
Cuneiform cartilages
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In the human larynx, the cuneiform cartilages are two small, elongated pieces of yellow elastic cartilage, placed one on either side, in the aryepiglottic fold. The cuneiforms are paired cartilages that sit on top of and move with the arytenoids and they are located above and in front of the corniculate cartilages, and the presence of these two pairs of cartilages result in small bulges on the surface of the mucous membrane. Covered by the folds, the cuneiforms form the lateral aspect of the laryngeal inlet, while the corniculates form the posterior aspect. Function of the cuneiform cartilages is to support the vocal folds and they also provide a degree of solidity to the folds in which they are embedded. This article incorporates text in the domain from the 20th edition of Grays Anatomy
16.
Adam's apple
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The Adams apple, or laryngeal prominence is a feature of the human neck, and is the lump or protrusion that is formed by the angle of the thyroid cartilage surrounding the larynx. The structure of the Adams apple forms a bump under the skin and it is typically larger in adult males, in whom it is usually clearly visible and palpable. In females, the bump is less visible and is hardly perceived on the upper edge of the thyroid cartilage. The meeting point of the two portions of the cartilage generally forms an angle in men, while in women it forms an open arc. Although both sexes have an Adams apple it is considered to be a feature of adult males. Its development is considered a sexual characteristic of males that appears as a result of hormonal activity. Its level of development varies among individuals and the widening of that area in the larynx can occur suddenly and quickly. The Adams apple is more prominent in males than in females because of the difference in the size of the angle, 90° in males. The Adams apple, in conjunction with the cartilage which forms it, helps to protect the walls. Another function of the Adams apple is related to the deepening of the voice, during adolescence, the thyroid cartilage grows together with the larynx. Consequently, the laryngeal prominence grows in mainly in men. Together, a larger soundboard is made up in phonation apparatus and, as a result, cosmetic surgery to reduce the size of the Adams apple is called chondrolaryngoplasty. The surgery is effective, such that complications tend to be few and, there are two main theories as to the origin of the term Adams apple. The Brewers Dictionary of Phrase and Fable and the 1913 edition of Websters Dictionary point at an ancient belief that a piece of fruit was embedded in Adams throat. However, neither the Bible nor other Judeo-Christian or Islamic writings mention such a story, in fact, the biblical story does not even specify the type of fruit that Adam ate. Linguist Alexander Gode claimed that the Latin phrase to designate the laryngeal prominence was very probably translated incorrectly from the beginning, the phrase in Latin was pomum Adami. This, in turn, came from the Hebrew tappuach ha adam meaning apple of man. The confusion lies in the fact that in Hebrew language the proper name Adam literally means man, while the Hebrew word apple means swollen, thus in combination, proponents of this version contend that the subsequent phrases in Latin and other Romance languages represent a mistranslation from the start
17.
Cricothyroid ligament
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The cricothyroid ligament is composed of two parts, the median cricothyroid ligament along the midline and the lateral cricothyroid ligaments on each side. The median cricothyroid ligament is a band of white connective tissue that connects the front parts of the contiguous margins of the cricoid and thyroid cartilages. It is a thick and strong ligament, narrow above and broad below, each lateral ligament is known as the conus elasticus. The lateral cricothyroid ligament is overlapped on either side by laryngeal muscles, the conus elasticus is the lateral portion of the cricothyroid ligament. These anatomical structure have been called in different ways in the past. This ligament is cut during emergency cricothyrotomy and this ligaments main purpose is to keep the cricoid and thyroid from traveling too far. This article incorporates text in the domain from the 20th edition of Grays Anatomy
18.
Swallowing
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Swallowing is an important part of eating and drinking. If the process fails and the material goes through the trachea, in the human body the automatic temporary closing of the epiglottis is controlled by the swallowing reflex. The portion of food, drink, or other material that will move through the neck in one swallow is called a bolus, eating and swallowing are complex neuromuscular activities consisting essentially of three phases, an oral, pharyngeal and esophageal phase. Each phase is controlled by a different neurological mechanism, the pharyngeal swallow is started by the oral phase and subsequently is co-ordinated by the swallowing center on the medulla oblongata and pons. The reflex is initiated by touch receptors in the pharynx as a bolus of food is pushed to the back of the mouth by the tongue, Swallowing is a complex mechanism using both skeletal muscle and smooth muscles of the pharynx and esophagus. The autonomic nervous system coordinates this process in the pharyngeal and esophageal phases, prior to the following stages of the oral phase, the mandible depresses and the lips abduct to allow food or liquid to enter the oral cavity. Upon entering the cavity, the mandible elevates and the lips adduct to assist in oral containment of the food. The following stages describe the normal and necessary actions to form the bolus, 1) Moistening Food is moistened by saliva from the salivary glands. 2) Mastication Food is mechanically broken down by the action of the controlled by the muscles of mastication acting on the temporomandibular joint. This results in a bolus which is moved from one side of the cavity to the other by the tongue. Buccinator helps to contain the food against the occlusal surfaces of the teeth, the bolus is ready for swallowing when it is held together by saliva, sensed by the lingual nerve of the tongue. Any food that is too dry to form a bolus will not be swallowed, 3) Trough formation A trough is then formed at the back of the tongue by the intrinsic muscles. The trough obliterates against the palate from front to back. The intrinsic muscles of the contract to make a trough at the back of the tongue. The tongue is then elevated to the roof of the mouth such that the tongue slopes downwards posteriorly, the contraction of the genioglossus and styloglossus also contributes to the formation of the central trough. 4) Movement of the bolus posteriorly At the end of the preparatory phase. In order for anterior to posterior transit of the bolus to occur, next, the superior longitudinal muscle elevates the apex of the tongue to make contact with the hard palate and the bolus is propelled to the posterior portion of the oral cavity. Once the bolus reaches the palatoglossal arch of the oropharynx, the pharyngeal phase, receptors initiating this reflex are proprioceptive
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Posterior cricoarytenoid muscle
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The posterior cricoarytenoid muscles are small, paired muscles that extend from the posterior cricoid cartilage to the arytenoid cartilages in the larynx. The posterior cricoarytenoid muscles receive innervation from the recurrent laryngeal branch of the vagus nerve, the posterior cricoarytenoid muscles are the only muscles to open the vocal cords. By rotating the arytenoid cartilages laterally, these muscles abduct the vocal cords and their action opposes the lateral cricoarytenoid muscles. Paralysis of the posterior cricoarytenoid muscles may lead to asphyxiation as they are the only muscles to open the true vocal folds. Recurrent laryngeal nerve Atlas image, rsa4p2 at the University of Michigan Health System lesson11 at The Anatomy Lesson by Wesley Norman
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Thyroarytenoid muscle
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The thyroarytenoid muscle is a broad, thin muscle that forms the body of the vocal fold and that supports the wall of the ventricle and its appendix. It functions to relax the vocal folds and it arises in front from the lower half of the angle of the thyroid cartilage, and from the middle cricothyroid ligament. Its fibers pass backward and laterally, to be inserted into the base, the vocal muscle is the upper portion of the thyroarytenoid muscle which is primarily involved in producing speech. A considerable number of the fibers of the muscle are prolonged into the aryepiglottic fold. They have received a name, thyroepiglottic muscle, thyreoepiglotticus or thyroepiglottic. A few fibers extend along the wall of the ventricle from the wall of the arytenoid cartilage to the side of the epiglottis. The thyroarytenoid muscle, consisting of two parts having different attachments and different directions, are rather complicated as regards their action and their main use is to draw the arytenoid cartilages forward toward the thyroid, and thus relax and shorten the vocal folds
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Extraocular muscles
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The extraocular muscles are the six muscles that control movement of the eye and one muscle that controls eyelid elevation. The actions of the six muscles responsible for eye movement depend on the position of the eye at the time of muscle contraction, since only a small part of the eye called the fovea provides sharp vision, the eye must move to follow a target. Eye movements must be precise and fast and this is seen in scenarios like reading, where the reader must shift gaze constantly. Although under voluntary control, most eye movement is accomplished without conscious effort, precisely how the integration between voluntary and involuntary control of the eye occurs is a subject of continuing research. It is known, however, that the vestibulo-ocular reflex plays an important role in the movement of the eye. The extraocular muscles are supplied mainly by branches of the ophthalmic artery and this is done either directly or indirectly, as in the lateral rectus muscle, via the lacrimal artery, a main branch of the ophthalmic artery. Additional branches of the ophthalmic artery include the ciliary arteries, which branch into the ciliary arteries. Each rectus muscle receives blood from two anterior ciliary arteries, except for the rectus muscle, which receives blood from only one. The exact number and arrangement of these cilary arteries may vary, branches of the infraorbital artery supply the inferior rectus and inferior oblique muscles. Below is a table of each of the muscles and their innervation, origins and insertions. Note that the muscles may have minor actions in neutral, adduction, or abduction, Obliques Abduct whereas Rectii Adduct 2. Superiors Intort whereas Inferior Extort 3, Rectii act according to their names whereas Obliques act opposite to their names. The nuclei or bodies of nerves are found in the brain stem. The nuclei of the abducens and oculomotor nerves are connected and this is important in coordinating motion of the lateral rectus in one eye and the medial action on the other. In one eye, in two antagonistic muscles, like the lateral and medial recti, contraction of one leads to inhibition of the other, muscles shows small degrees of activity even when resting, keeping the muscles taut. This tonic activity is brought on by discharges of the nerve to the muscle. Four of the muscles have their origin in the back of the orbit in a fibrous ring called the annulus of Zinn. The four rectus muscles attach directly to the front half of the eye, note that medial and lateral are relative terms
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Omohyoid muscle
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The omohyoid muscle is a muscle that depresses the hyoid. It is located at the front of the neck and consists of two separated by an intermediate tendon. Its superior belly serves as the most lateral member of the infrahyoid muscles and its name derives from the Greek omos meaning shoulder, giving one of its attachments, and hyoid, giving the other attachment - the hyoid bone.5 cm. This muscle has two separate bellies, superior and inferior, the tendon overlies the internal jugular vein, and can be used as a landmark for this vein during surgery. Doubling, absence, origin from clavicle, absence or doubling of either belly, the inferior belly of the omohyoid divides the posterior triangle of the neck into an upper or occipital triangle and a lower or subclavian triangle. Its superior belly divides the triangle into an upper or carotid triangle. The Omohyoid muscle is attached to the scapula and distally attached to the hyoid bone. The omohyoid is innervated by a branch of the plexus, the ansa cervicalis
. PMID 26109185.