Anatomy (from Ancient Greekἀνατομή (anatomḗ)'dissection') is the branch ofmorphology concerned with the study of the internal structure oforganisms and their parts.[2] Anatomy is a branch ofnatural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times.[3] Anatomy is inherently tied todevelopmental biology,embryology,comparative anatomy,evolutionary biology, andphylogeny,[4] as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy andphysiology, which study the structure andfunction of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together.Human anatomy is one of the essentialbasic sciences that are applied in medicine, and is often studied alongsidephysiology.[5]
Anatomy is a complex and dynamic field that is constantly evolving as discoveries are made. In recent years, there has been a significant increase in the use of advanced imaging techniques, such asMRI andCT scans, which allow for more detailed and accurate visualizations of the body's structures.
The discipline of anatomy is divided intomacroscopic andmicroscopic parts.Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch ofsuperficial anatomy. Microscopic anatomy involves the use of optical instruments in the study of thetissues of various structures, known ashistology, and also in the study ofcells.
Derived from the Greekἀνατομήanatomē "dissection" (fromἀνατέμνωanatémnō "I cut up, cut open" from ἀνάaná "up", and τέμνωtémnō "I cut"),[8] anatomy is the scientific study of the structure oforganisms including their systems,organs andtissues. It includes the appearance and position of the various parts, the materials from which they are composed, and their relationships with other parts. Anatomy is quite distinct fromphysiology andbiochemistry, which deal respectively with the functions of those parts and the chemical processes involved. For example, an anatomist is concerned with the shape, size, position, structure, blood supply and innervation of an organ such as the liver; while a physiologist is interested in the production ofbile, the role of the liver in nutrition and the regulation of bodily functions.[9]
The discipline of anatomy can be subdivided into a number of branches, including gross ormacroscopic anatomy andmicroscopic anatomy.[10]Gross anatomy is the study of structures large enough to be seen with the naked eye, and also includessuperficial anatomy or surface anatomy, the study by sight of the external body features.Microscopic anatomy is the study of structures on a microscopic scale, along withhistology (the study of tissues), andembryology (the study of an organism in its immature condition).[4] Regional anatomy is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen. In contrast, systemic anatomy is the study of the structures that make up a discrete body system—that is, a group of structures that work together to perform a unique body function, such as the digestive system.[11]
Anatomy can be studied using both invasive and non-invasive methods with the goal of obtaining information about the structure and organization of organs and systems.[4] Methods used includedissection, in which a body is opened and its organs studied, andendoscopy, in which avideo camera-equipped instrument is inserted through a small incision in the body wall and used to explore the internal organs and other structures.Angiography usingX-rays ormagnetic resonance angiography are methods to visualize blood vessels.[12][13][14][15]
The term "anatomy" is commonly taken to refer tohuman anatomy. However, substantially similar structures and tissues are found throughout the rest of the animal kingdom, and the term also includes the anatomy of other animals. The termzootomy is also sometimes used to specifically refer to non-human animals. The structure and tissues of plants are of a dissimilar nature and they are studied inplant anatomy.[9]
Unlikeplant cells,animal cells have neither a cell wall norchloroplasts. Vacuoles, when present, are more in number and much smaller than those in the plant cell. The body tissues are composed of numerous types of cells, including those found in muscles, nerves and skin. Each typically has a cell membrane formed ofphospholipids,cytoplasm and anucleus. All of the different cells of an animal are derived from the embryonicgerm layers. Those simpler invertebrates which are formed from two germ layers of ectoderm and endoderm are calleddiploblastic and the more developed animals whose structures and organs are formed from three germ layers are calledtriploblastic.[17] All of a triploblastic animal's tissues and organs are derived from the three germ layers of the embryo, theectoderm,mesoderm andendoderm.
Connective tissues are fibrous and made up of cells scattered among inorganic material called theextracellular matrix. Often calledfascia (from the Latin "fascia," meaning "band" or "bandage"), connective tissues give shape to organs and holds them in place. The main types are loose connective tissue,adipose tissue, fibrous connective tissue,cartilage and bone. The extracellular matrix containsproteins, the chief and most abundant of which iscollagen. Collagen plays a major part in organizing and maintaining tissues. The matrix can be modified to form a skeleton to support or protect the body. Anexoskeleton is a thickened, rigidcuticle which is stiffened bymineralization, as incrustaceans or by the cross-linking of its proteins as ininsects. Anendoskeleton is internal and present in all developed animals, as well as in many of those less developed.[17]
Epithelial tissue is composed of closely packed cells, bound to each other bycell adhesion molecules, with little intercellular space. Epithelial cells can besquamous (flat),cuboidal orcolumnar and rest on abasal lamina, the upper layer of thebasement membrane,[18] the lower layer is the reticular lamina lying next to the connective tissue in the extracellular matrix secreted by the epithelial cells.[19] There are many different types of epithelium, modified to suit a particular function. In therespiratory tract there is a type ofciliated epithelial lining; in the small intestine there aremicrovilli on the epithelial lining and in the large intestine there areintestinal villi. Skin consists of an outer layer ofkeratinized stratified squamous epithelium that covers the exterior of the vertebrate body.Keratinocytes make up to 95% of the cells in theskin.[20] The epithelial cells on the external surface of the body typically secrete an extracellular matrix in the form of acuticle. In simple animals this may just be a coat ofglycoproteins.[17] In more advanced animals, manyglands are formed of epithelial cells.[21]
Muscle cells (myocytes) form the active contractile tissue of the body.Muscle tissue functions to produce force and cause motion, either locomotion or movement within internal organs. Muscle is formed of contractilefilaments and is separated into three main types;smooth muscle,skeletal muscle andcardiac muscle. Smooth muscle has nostriations when examined microscopically. It contracts slowly but maintains contractibility over a wide range of stretch lengths. It is found in such organs assea anemone tentacles and the body wall ofsea cucumbers. Skeletal muscle contracts rapidly but has a limited range of extension. It is found in the movement of appendages and jaws. Obliquely striated muscle is intermediate between the other two. The filaments are staggered and this is the type of muscle found inearthworms that can extend slowly or make rapid contractions.[22] In higher animals striated muscles occur in bundles attached to bone to provide movement and are often arranged in antagonistic sets. Smooth muscle is found in the walls of theuterus,bladder,intestines,stomach,oesophagus,respiratory airways, andblood vessels.Cardiac muscle is found only in theheart, allowing it to contract and pump blood round the body.
Mouse skull. The neck and most of the forelimbs are also seen.
Allvertebrates have a similar basicbody plan and at some point in their lives, mostly in theembryonic stage, share the majorchordate characteristics: a stiffening rod, thenotochord; a dorsal hollow tube of nervous material, theneural tube;pharyngeal arches; and a tail posterior to the anus. Thespinal cord is protected by thevertebral column and is above the notochord, and thegastrointestinal tract is below it.[27] Nervous tissue is derived from theectoderm, connective tissues are derived frommesoderm, and gut is derived from theendoderm. At the posterior end is a tail which continues the spinal cord and vertebrae but not the gut. The mouth is found at the anterior end of the animal, and theanus at the base of the tail.[28] The defining characteristic of a vertebrate is thevertebral column, formed in the development of the segmented series ofvertebrae. In most vertebrates the notochord becomes thenucleus pulposus of theintervertebral discs. However, a few vertebrates, such as thesturgeon and thecoelacanth, retain the notochord into adulthood.[29]Jawed vertebrates are typified by paired appendages, fins or legs, which may be secondarily lost. The limbs of vertebrates are considered to behomologous because the same underlying skeletal structure was inherited from theirlast common ancestor. This is one of the arguments put forward byCharles Darwin to support his theory ofevolution.[30]
The body of afish is divided into a head, trunk and tail, although the divisions between the three are not always externally visible. The skeleton, which forms the support structure inside the fish, is either made of cartilage, incartilaginous fish, or bone inbony fish. The main skeletal element is the vertebral column, composed of articulatingvertebrae which are lightweight yet strong. The ribs attach to the spine and there are nolimbs or limb girdles. The main external features of the fish, thefins, are composed of either bony or soft spines called rays, which with the exception of thecaudal fins, have no direct connection with the spine. They are supported by the muscles which compose the main part of the trunk.[31] The heart has two chambers and pumps the blood through the respiratory surfaces of thegills and on round the body in a single circulatory loop.[32] The eyes are adapted for seeing underwater and have only local vision. There is an inner ear but no external ormiddle ear. Low frequency vibrations are detected by thelateral line system of sense organs that run along the length of the sides of fish, and these respond to nearby movements and to changes in water pressure.[31]
Sharks and rays arebasal fish with numerousprimitive anatomical features similar to those of ancient fish, including skeletons composed of cartilage. Their bodies tend to be dorso-ventrally flattened, they usually have five pairs of gill slits and a large mouth set on the underside of the head. The dermis is covered with separate dermalplacoid scales. They have acloaca into which the urinary and genital passages open, but not aswim bladder. Cartilaginous fish produce a small number of large,yolky eggs. Some species areovoviviparous and the young develop internally but others areoviparous and the larvae develop externally in egg cases.[33]
The bony fish lineage shows morederived anatomical traits, often with major evolutionary changes from the features of ancient fish. They have a bony skeleton, are generally laterally flattened, have five pairs of gills protected by anoperculum, and a mouth at or near the tip of the snout. The dermis is covered with overlappingscales. Bony fish have a swim bladder which helps them maintain a constant depth in the water column, but not a cloaca. They mostlyspawn a large number of small eggs with little yolk which they broadcast into the water column.[33]
Amphibians are aclass of animals comprisingfrogs,salamanders andcaecilians. They aretetrapods, but the caecilians and a few species of salamander have either no limbs or their limbs are much reduced in size. Their main bones are hollow and lightweight and are fully ossified and the vertebrae interlock with each other and havearticular processes. Their ribs are usually short and may be fused to the vertebrae. Their skulls are mostly broad and short, and are often incompletely ossified. Their skin contains littlekeratin and lacks scales, but contains manymucous glands and in some species, poison glands. The hearts of amphibians have three chambers, twoatria and oneventricle. They have aurinary bladder andnitrogenous waste products are excreted primarily asurea. Amphibians breathe by means ofbuccal pumping, a pump action in which air is first drawn into thebuccopharyngeal region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat.[34] They supplement this withgas exchange through the skin which needs to be kept moist.[35]
In frogs the pelvic girdle is robust and the hind legs are much longer and stronger than the forelimbs. The feet have four or five digits and the toes are often webbed for swimming or have suction pads for climbing. Frogs have large eyes and no tail. Salamanders resemble lizards in appearance; their short legs project sideways, the belly is close to or in contact with the ground and they have a long tail. Caecilians superficially resembleearthworms and are limbless. They burrow by means of zones of muscle contractions which move along the body and they swim by undulating their body from side to side.[36]
Reptiles are a class ofanimals comprisingturtles,tuataras,lizards,snakes andcrocodiles. They aretetrapods, but the snakes and a few species of lizard either have no limbs or their limbs are much reduced in size. Their bones are better ossified and their skeletons stronger than those of amphibians. The teeth are conical and mostly uniform in size. The surface cells of the epidermis are modified into horny scales which create a waterproof layer. Reptiles are unable to use their skin for respiration as do amphibians and have a more efficient respiratory system drawing air into theirlungs by expanding their chest walls. The heart resembles that of the amphibian but there is a septum which more completely separates the oxygenated and deoxygenated bloodstreams. The reproductive system has evolved for internal fertilization, with acopulatory organ present in most species. The eggs are surrounded byamniotic membranes which prevents them from drying out and are laid on land, ordevelop internally in some species. The bladder is small as nitrogenous waste is excreted asuric acid.[37]
Turtles are notable for their protective shells. They have an inflexible trunk encased in a hornycarapace above and aplastron below. These are formed from bony plates embedded in the dermis which are overlain by horny ones and are partially fused with the ribs and spine. The neck is long and flexible and the head and the legs can be drawn back inside the shell. Turtles are vegetarians and the typical reptile teeth have been replaced by sharp, horny plates. In aquatic species, the front legs are modified into flippers.[38]
Tuataras superficially resemble lizards but the lineages diverged in theTriassic period. There is one living species,Sphenodon punctatus. The skull has two openings (fenestrae) on either side and the jaw is rigidly attached to the skull. There is one row of teeth in the lower jaw and this fits between the two rows in the upper jaw when the animal chews. The teeth are merely projections of bony material from the jaw and eventually wear down. The brain and heart are more primitive than those of other reptiles, and the lungs have a single chamber and lackbronchi. The tuatara has a well-developedparietal eye on its forehead.[38]
Lizards have skulls with only onefenestra on each side, the lower bar of bone below the second fenestra having been lost. This results in the jaws being less rigidly attached which allows the mouth to open wider. Lizards are mostly quadrupeds, with the trunk held off the ground by short, sideways-facing legs, but a few species have no limbs and resemble snakes. Lizards have moveable eyelids, eardrums are present and some species have a central parietal eye.[38]
Snakes are closely related to lizards, having branched off from a common ancestral lineage during theCretaceous period, and they share many of the same features. The skeleton consists of a skull, a hyoid bone, spine and ribs though a few species retain a vestige of the pelvis and rear limbs in the form ofpelvic spurs. The bar under the second fenestra has also been lost and the jaws have extreme flexibility allowing the snake to swallow its prey whole. Snakes lack moveable eyelids, the eyes being covered by transparent "spectacle" scales. They do not have eardrums but can detect ground vibrations through the bones of their skull. Their forked tongues are used as organs of taste and smell and some species have sensory pits on their heads enabling them to locate warm-blooded prey.[39]
Crocodilians are large, low-slung aquatic reptiles with long snouts and large numbers of teeth. The head and trunk are dorso-ventrally flattened and the tail is laterally compressed. It undulates from side to side to force the animal through the water when swimming. The tough keratinized scales provide body armour and some are fused to the skull. The nostrils, eyes and ears are elevated above the top of the flat head enabling them to remain above the surface of the water when the animal is floating. Valves seal the nostrils and ears when it is submerged. Unlike other reptiles, crocodilians have hearts with four chambers allowing complete separation of oxygenated and deoxygenated blood.[40]
Birds aretetrapods but though their hind limbs are used for walking or hopping, their front limbs arewings covered withfeathers and adapted for flight. Birds areendothermic, have a highmetabolic rate, a lightskeletal system and powerfulmuscles. The long bones are thin, hollow and very light. Air sac extensions from the lungs occupy the centre of some bones. The sternum is wide and usually has a keel and the caudal vertebrae are fused. There are no teeth and the narrow jaws are adapted into a horn-covered beak. The eyes are relatively large, particularly in nocturnal species such as owls. They face forwards in predators and sideways in ducks.[41]
The feathers are outgrowths of theepidermis and are found in localized bands from where they fan out over the skin. Large flight feathers are found on the wings and tail, contour feathers cover the bird's surface and fine down occurs on young birds and under the contour feathers of water birds. The only cutaneous gland is the singleuropygial gland near the base of the tail. This produces an oily secretion that waterproofs the feathers when the birdpreens. There are scales on the legs, feet and claws on the tips of the toes.[41]
Mammals are a diverse class of animals, mostly terrestrial but some are aquatic and others have evolved flapping or gliding flight. They mostly have four limbs, but some aquatic mammals have no limbs or limbs modified into fins, and the forelimbs of bats are modified into wings. The legs of most mammals are situated below the trunk, which is held well clear of the ground. The bones of mammals are well ossified and their teeth, which are usually differentiated, are coated in a layer ofprismatic enamel. The teeth are shed once (milk teeth) during the animal's lifetime or not at all, as is the case incetaceans. Mammals have three bones in the middle ear and acochlea in theinner ear. They are clothed in hair and their skin contains glands which secretesweat. Some of these glands are specialized asmammary glands, producing milk to feed the young. Mammals breathe withlungs and have a musculardiaphragm separating the thorax from the abdomen which helps them draw air into the lungs. The mammalian heart has four chambers, and oxygenated and deoxygenated blood are kept entirely separate. Nitrogenous waste is excreted primarily as urea.[42]
Mammals areamniotes, and most areviviparous, giving birth to live young. Exceptions to this are the egg-layingmonotremes, theplatypus and theechidnas of Australia. Most other mammals have aplacenta through which the developingfoetus obtains nourishment, but inmarsupials, the foetal stage is very short and the immature young is born and finds its way to its mother'spouch where it latches on to ateat and completes its development.[42]
Sagittal sections of the head as seen by a modernMRI scanIn humans, dexterous hand movements and increased brain size are likely to have evolved simultaneously.[43]
Humans have the overall body plan of a mammal. Humans have a head, neck,trunk (which includes thethorax andabdomen), two arms and hands, and two legs and feet.
Generally, students of certainbiological sciences,paramedics, prosthetists and orthotists,physiotherapists,occupational therapists,nurses,podiatrists, andmedical students learn gross anatomy and microscopic anatomy from anatomical models, skeletons, textbooks, diagrams, photographs, lectures and tutorials and in addition, medical students generally also learn gross anatomy through practical experience ofdissection and inspection ofcadavers. The study of microscopic anatomy (orhistology) can be aided by practical experience examining histological preparations (or slides) under amicroscope.[44]
Human anatomy, physiology and biochemistry are complementary basic medical sciences, which are generally taught to medical students in their first year at medical school. Human anatomy can be taught regionally or systemically; that is, respectively, studying anatomy by bodily regions such as the head and chest, or studying by specific systems, such as the nervous or respiratory systems.[4] The major anatomy textbook,Gray's Anatomy, has been reorganized from a systems format to a regional format, in line with modern teaching methods.[45][46] A thorough working knowledge of anatomy is required by physicians, especiallysurgeons and doctors working in some diagnostic specialties, such ashistopathology andradiology.[47]
Academic anatomists are usually employed by universities, medical schools or teaching hospitals. They are often involved in teaching anatomy, and research into certain systems, organs, tissues or cells.[47]
Invertebrates constitute a vast array of living organisms ranging from the simplest unicellulareukaryotes such asParamecium to such complex multicellular animals as theoctopus,lobster anddragonfly. They constitute about 95% of the animal species. By definition, none of these creatures has a backbone. The cells of single-cellprotozoans have the same basic structure as those of multicellular animals but some parts are specialized into the equivalent of tissues and organs. Locomotion is often provided bycilia orflagella or may proceed via the advance ofpseudopodia, food may be gathered byphagocytosis, energy needs may be supplied byphotosynthesis and the cell may be supported by anendoskeleton or anexoskeleton. Some protozoans can form multicellular colonies.[48]
Metazoans are a multicellular organism, with different groups of cells serving different functions. The most basic types of metazoan tissues are epithelium and connective tissue, both of which are present in nearly all invertebrates. The outer surface of the epidermis is normally formed of epithelial cells and secretes anextracellular matrix which provides support to the organism. An endoskeleton derived from themesoderm is present inechinoderms,sponges and somecephalopods.Exoskeletons are derived from the epidermis and is composed ofchitin inarthropods (insects, spiders, ticks, shrimps, crabs, lobsters).Calcium carbonate constitutes the shells ofmolluscs,brachiopods and some tube-buildingpolychaete worms andsilica forms the exoskeleton of the microscopicdiatoms andradiolaria.[49] Other invertebrates may have no rigid structures but the epidermis may secrete a variety of surface coatings such as thepinacoderm of sponges, the gelatinous cuticle of cnidarians (polyps,sea anemones,jellyfish) and thecollagenous cuticle ofannelids. The outer epithelial layer may include cells of several types including sensory cells, gland cells and stinging cells. There may also be protrusions such asmicrovilli, cilia, bristles,spines andtubercles.[50]
Marcello Malpighi, the father of microscopical anatomy, discovered that plants had tubules similar to those he saw in insects like the silk worm. He observed that when a ring-like portion of bark was removed on a trunk a swelling occurred in the tissues above the ring, and he unmistakably interpreted this as growth stimulated by food coming down from the leaves, and being captured above the ring.[51]
Arthropods comprise the largest phylum ofinvertebrates in the animal kingdom with over a million known species.[52]
Insects possesssegmented bodies supported by a hard-jointed outer covering, theexoskeleton, made mostly ofchitin. The segments of the body are organized into three distinct parts, a head, athorax and anabdomen.[53] The head typically bears a pair of sensoryantennae, a pair ofcompound eyes, one to three simple eyes (ocelli) and three sets of modified appendages that form themouthparts. The thorax has three pairs of segmentedlegs, one pair each for the three segments that compose the thorax and one or two pairs ofwings. The abdomen is composed of eleven segments, some of which may be fused and houses thedigestive,respiratory,excretory and reproductive systems.[54] There is considerable variation between species and many adaptations to the body parts, especially wings, legs, antennae and mouthparts.[55]
Spiders a class ofarachnids have four pairs of legs; a body of two segments—acephalothorax and anabdomen. Spiders have no wings and no antennae. They have mouthparts calledchelicerae which are often connected to venom glands as most spiders are venomous. They have a second pair of appendages calledpedipalps attached to the cephalothorax. These have similar segmentation to the legs and function as taste and smell organs. At the end of each male pedipalp is a spoon-shaped cymbium that acts to support thecopulatory organ.
Surface anatomy is important as the study of anatomical landmarks that can be readily seen from the exterior contours of the body.[4] It enables medics andveterinarians to gauge the position and anatomy of the associated deeper structures. Superficial is a directional term that indicates that structures are located relatively close to the surface of the body.[56]
Comparative anatomy relates to the comparison of anatomical structures (both gross and microscopic) in different animals.[4]
Ancient Greek anatomy and physiology underwent great changes and advances throughout the early medieval world. Over time, this medical practice expanded due to a continually developing understanding of the functions of organs and structures in the body. Phenomenal anatomical observations of the human body were made, which contributed to the understanding of the brain, eye, liver, reproductive organs, and nervous system.
TheHellenistic Egyptian city ofAlexandria was the stepping-stone for Greek anatomy and physiology. Alexandria not only housed the biggest library for medical records and books of the liberal arts in the world during the time of the Greeks but was also home to many medical practitioners and philosophers. Great patronage of the arts and sciences from thePtolemaic dynasty of Egypt helped raise Alexandria up, further rivalling other Greek states' cultural and scientific achievements.[61]
Some of the most striking advances in early anatomy and physiology took place in Hellenistic Alexandria.[61] Two of the most famous anatomists and physiologists of the third century wereHerophilus andErasistratus. These two physicians helped pioneer humandissection for medical research, using the cadavers of condemned criminals, which was considered taboo until the Renaissance—Herophilus was recognized as the first person to perform systematic dissections.[62] Herophilus became known for his anatomical works, making impressive contributions to many branches of anatomy and many other aspects of medicine.[63] Some of the works included classifying the system of the pulse, the discovery that human arteries had thicker walls than veins, and that the atria were parts of the heart. Herophilus's knowledge of the human body has provided vital input towards understanding the brain, eye, liver, reproductive organs, and nervous system and characterizing the course of the disease.[62] Erasistratus accurately described the structure of the brain, including the cavities and membranes, and made a distinction between its cerebrum and cerebellum[64] During his study in Alexandria, Erasistratus was particularly concerned with studies of the circulatory and nervous systems. He could distinguish the human body's sensory and motor nerves and believed air entered the lungs and heart, which was then carried throughout the body. His distinction between the arteries and veins—the arteries carrying the air through the body, while the veins carry the blood from the heart was a great anatomical discovery. Erasistratus was also responsible for naming and describing the function of the epiglottis and the heart's valves, including the tricuspid.[65] During the third century, Greek physicians were able to differentiate nerves from blood vessels and tendons[66] and to realize that the nerves convey neural impulses.[61] It was Herophilus who made the point that damage to motor nerves induced paralysis.[62] Herophilus named the meninges and ventricles in the brain, appreciated the division between cerebellum and cerebrum and recognized that the brain was the "seat of intellect" and not a "cooling chamber" as propounded by Aristotle[67] Herophilus is also credited with describing the optic, oculomotor, motor division of the trigeminal, facial, vestibulocochlear and hypoglossal nerves.[68]
Surgical instruments were invented byAbulcasis in the 11th centuryAnatomy of the eye for the first time in history byHunayn ibn Ishaq in the 9th century13th century anatomical illustration
Incredible feats were made during the third century BCE in both the digestive and reproductive systems. Herophilus discovered and described not only the salivary glands but also the small intestine and liver.[68] He showed that the uterus is a hollow organ and described the ovaries and uterine tubes. He recognized that spermatozoa were produced by the testes and was the first to identify the prostate gland.[68]
In the 2nd century,Galen of Pergamum, an anatomist,clinician, writer, and philosopher,[72] wrote the final and highly influential anatomy treatise of ancient times.[73] He compiled existing knowledge and studied anatomy through the dissection of animals.[72] He was one of the first experimental physiologists through hisvivisection experiments on animals.[74] Galen's drawings, based mostly on dog anatomy, became effectively the only anatomical textbook for the next thousand years.[75] His work was known toRenaissance doctors only throughIslamic Golden Age medicine until it was translated from Greek sometime in the 15th century.[75]
Anatomy developed little from classical times until the sixteenth century; as the historian Marie Boas writes, "Progress in anatomy before the sixteenth century is as mysteriously slow as its development after 1500 is startlingly rapid".[75]: 120–121 Between 1275 and 1326, the anatomistsMondino de Luzzi,Alessandro Achillini andAntonio Benivieni atBologna carried out the first systematic human dissections since ancient times.[76][77][78] Mondino'sAnatomy of 1316 was the first textbook in the medieval rediscovery of human anatomy. It describes the body in the order followed in Mondino's dissections, starting with the abdomen, thorax, head, and limbs. It was the standard anatomy textbook for the next century.[75]
Leonardo da Vinci (1452–1519) was trained in anatomy byAndrea del Verrocchio.[75] He made use of his anatomical knowledge in his artwork, making many sketches of skeletal structures, muscles and organs of humans and other vertebrates that he dissected.[75][79]
Andreas Vesalius (1514–1564), professor of anatomy at theUniversity of Padua, is considered the founder of modern human anatomy.[80] Originally fromBrabant, Vesalius published the influential bookDe humani corporis fabrica ("the structure of the human body"), a large format book in seven volumes, in 1543.[81] The accurate and intricately detailed illustrations, often inallegorical poses against Italianate landscapes, are thought to have been made by the artistJan van Calcar, a pupil ofTitian.[82]
In England, anatomy was the subject of the first public lectures given in any science; these were provided by theCompany of Barbers and Surgeons in the 16th century, joined in 1583 by the Lumleian lectures in surgery at theRoyal College of Physicians.[83]
Medical schools began to be set up in the United States towards the end of the 18th century. Classes in anatomy needed a continual stream of cadavers for dissection, and these were difficult to obtain. Philadelphia, Baltimore, and New York were all renowned forbody snatching activity as criminals raided graveyards at night, removing newly buried corpses from their coffins.[84] A similar problem existed in Britain where demand for bodies became so great that grave-raiding and evenanatomy murder were practised to obtain cadavers.[85] Some graveyards were, in consequence, protected with watchtowers. The practice was halted in Britain by theAnatomy Act of 1832,[86][87] while in the United States, similar legislation was enacted after the physicianWilliam S. Forbes ofJefferson Medical College was found guilty in 1882 of "complicity with resurrectionists in the despoliation of graves in Lebanon Cemetery".[88]
The teaching of anatomy in Britain was transformed by SirJohn Struthers,Regius Professor of Anatomy at theUniversity of Aberdeen from 1863 to 1889. He was responsible for setting up the system of three years of "pre-clinical" academic teaching in the sciences underlying medicine, including especially anatomy. This system lasted until the reform of medical training in 1993 and 2003. As well as teaching, he collected many vertebrate skeletons for his museum ofcomparative anatomy, published over 70 research papers, and became famous for his public dissection of theTay Whale.[89][90] From 1822 the Royal College of Surgeons regulated the teaching of anatomy in medical schools.[91] Medical museums provided examples in comparative anatomy, and were often used in teaching.[92]Ignaz Semmelweis investigatedpuerperal fever and he discovered how it was caused. He noticed that the frequently fatal fever occurred more often in mothers examined by medical students than by midwives. The students went from the dissecting room to the hospital ward and examined women in childbirth. Semmelweis showed that when the trainees washed their hands in chlorinated lime before each clinical examination, the incidence of puerperal fever among the mothers could be reduced dramatically.[93]
An electron microscope from 1973
Before the modern medical era, the primary means for studying the internal structures of the body weredissection of the dead andinspection,palpation, andauscultation of the living. The advent ofmicroscopy opened up an understanding of the building blocks that constituted living tissues. Technical advances in the development ofachromatic lenses increased theresolving power of the microscope, and around 1839,Matthias Jakob Schleiden andTheodor Schwann identified that cells were the fundamental unit of organization of all living things. The study of small structures involved passing light through them, and themicrotome was invented to provide sufficiently thin slices of tissue to examine. Staining techniques using artificial dyes were established to help distinguish between different tissue types. Advances in the fields ofhistology andcytology began in the late 19th century[94] along with advances in surgical techniques allowing for the painless and safe removal ofbiopsy specimens. The invention of theelectron microscope brought a significant advance in resolution power and allowed research into theultrastructure of cells and theorganelles and other structures within them. About the same time, in the 1950s, the use ofX-ray diffraction for studying the crystal structures of proteins, nucleic acids, and other biological molecules gave rise to a new field ofmolecular anatomy.[94]
Equally important advances have occurred innon-invasive techniques for examining the body's interior structures.X-rays can be passed through the body and used in medicalradiography andfluoroscopy to differentiate interior structures that have varying degrees of opaqueness.Magnetic resonance imaging,computed tomography, andultrasound imaging have all enabled the examination of internal structures in unprecedented detail to a degree far beyond the imagination of earlier generations.[7]
^abBozman, E. F., ed. (1967).Everyman's Encyclopedia: Anatomy. J. M. Dent & Sons. p. 272.ASINB0066E44EC.
^"Anatomy".The Free Dictionary. Farlex. 2007.Archived from the original on 15 November 2018. Retrieved8 July 2013.
^J. Gordon Betts (2013). "1.1 Overview of Anatomy and Physiology".Anatomy & physiology. Houston, Texas: OpenStax.ISBN978-1-947172-04-3.Archived from the original on 3 April 2023. Retrieved14 May 2023.
^Benson KG, Forrest L (1999). "Characterization of the Renal Portal System of the Common Green Iguana (Iguana iguana) by Digital Subtraction Imaging".Journal of Zoo and Wildlife Medicine.30 (2):235–241.PMID10484138.
^abcRuppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).Invertebrate Zoology, 7th edition.Cengage Learning. pp. 59–60.ISBN978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Dorland's (2012).Illustrated Medical Dictionary. Elsevier Saunders. p. 203.ISBN978-1-4160-6257-8.
^Dorland's (2012).Illustrated Medical Dictionary. Elsevier Saunders. p. 1002.ISBN978-1-4160-6257-8.
^McGrath, J.A.; Eady, R.A.; Pope, F.M. (2004). Rook's Textbook of Dermatology (7th ed.). Blackwell Publishing. pp. 3.1–3.6.ISBN978-0-632-06429-8.
^Bernd, Karen (2010)."Glandular epithelium".Epithelial Cells. Davidson College.Archived from the original on 28 January 2020. Retrieved25 June 2013.
^Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).Invertebrate Zoology, 7th edition. Cengage Learning. p. 103.ISBN978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).Invertebrate Zoology, 7th edition. Cengage Learning. p. 104.ISBN978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Johnston, T.B; Whillis, J, eds. (1944).Grey's Anatomy: Descriptive and Applied (28 ed.). Langmans. p. 1038.
^Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).Invertebrate Zoology, 7th edition. Cengage Learning. pp. 105–107.ISBN978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Moore, K.; Agur, A.; Dalley, A. F. (2010)."Essesntial Clinical Anatomy".Nervous System (4th ed.). Inkling.Archived from the original on 8 March 2021. Retrieved30 April 2014.
^Romer, Alfred Sherwood (1985).The Vertebrate Body. Holt Rinehart & Winston.ISBN978-0-03-058446-6.
^Liem, Karel F.; Warren Franklin Walker (2001).Functional anatomy of the vertebrates: an evolutionary perspective. Harcourt College Publishers. p. 277.ISBN978-0-03-022369-3.
^"What is Homology?". National Center for Science Education. 17 October 2008.Archived from the original on 31 March 2019. Retrieved28 June 2013.
^Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).Invertebrate Zoology, 7th edition. Cengage Learning. pp. 23–24.ISBN978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^"Exoskeleton".Encyclopædia Britannica.Archived from the original on 3 May 2015. Retrieved2 July 2013.
^Ebling, F. J. G."Integument".Encyclopædia Britannica.Archived from the original on 30 April 2015. Retrieved2 July 2013.
^Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).Invertebrate Zoology, 7th edition. Cengage Learning. pp. 218–225.ISBN978-81-315-0104-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
^Marieb, Elaine (2010).Human Anatomy & Physiology. San Francisco: Pearson. p. 12.
^Boehm, Thomas; Bleul, Conrad C. (February 2007)."The evolutionary history of lymphoid organs".Nature Immunology.8 (2):131–135.doi:10.1038/ni1435.ISSN1529-2908.PMID17242686.S2CID45581056.Archived from the original on 7 March 2023. Retrieved7 March 2023.Important landmark discoveries included the first description of the spleen found in the Edwin Smith Papyrus, containing medical information from Egypt dating back as early as 3000 BC...
^Porter, R. (1997).The Greatest Benefit to Mankind: A Medical History of Humanity from Antiquity to the Present. Harper Collins. pp. 49–50.ISBN978-0-00-215173-3.
^"Erasistratus Biography (304B.C-250B.C)".Free Health Encyclopedia - faqs.org. Archived from the original on 16 November 2018. Retrieved23 February 2022.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
^abHutton, Vivien."Galen of Pergamum".Encyclopædia Britannica 2006 Ultimate Reference Suite DVD.Archived from the original on 6 April 2012. Retrieved13 May 2014.
^Rosner, Lisa. 2010. The Anatomy Murders. Being the True and Spectacular History of Edinburgh's Notorious Burke and Hare and of the Man of Science Who Abetted Them in the Commission of Their Most Heinous Crimes. University of Pennsylvania Press
^Richardson, Ruth (1989).Death, Dissection, and the Destitute. Penguin.ISBN978-0-14-022862-5.
^Johnson, D.R."Introductory Anatomy". University of Leeds.Archived from the original on 4 November 2008. Retrieved25 June 2013.
^Reinarz J (2005). "The age of museum medicine: The rise and fall of the medical museum at Birmingham's School of Medicine".Social History of Medicine.18 (3):419–437.doi:10.1093/shm/hki050.
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