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Anatomy

Anatomy is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic sciences that are applied in medicine, and is often studied alongside physiology.

Anatomy is a complex and dynamic field that is constantly evolving as new discoveries are made. In recent years, there has been a significant increase in the use of advanced imaging techniques, such as MRI and CT scans, which allow for more detailed and accurate visualizations of the body's structures.

The discipline of anatomy is divided into macroscopic and microscopic parts. Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch of superficial anatomy. Microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology, and also in the study of cells.

The history of anatomy is characterized by a progressive understanding of the functions of the organs and structures of the human body. Methods have also improved dramatically, advancing from the examination of animals by dissection of carcasses and cadavers (corpses) to 20th-century medical imaging techniques, including X-ray, ultrasound, and magnetic resonance imaging.

Etymology and definition

Derived from the Greek ἀνατομή anatomē "dissection" (from ἀνατέμνω anatémnō "I cut up, cut open" from ἀνά aná "up", and τέμνω témnō "I cut"), anatomy is the scientific study of the structure of organisms including their systems, organs and tissues. 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 from physiology and biochemistry, 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 of bile, the role of the liver in nutrition and the regulation of bodily functions.

The discipline of anatomy can be subdivided into a number of branches, including gross or macroscopic anatomy and microscopic anatomy. Gross anatomy is the study of structures large enough to be seen with the naked eye, and also includes superficial 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 with histology (the study of tissues), and embryology (the study of an organism in its immature condition). 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.

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. Methods used include dissection, in which a body is opened and its organs studied, and endoscopy, in which a video camera-equipped instrument is inserted through a small incision in the body wall and used to explore the internal organs and other structures. Angiography using X-rays or magnetic resonance angiography are methods to visualize blood vessels.

The term "anatomy" is commonly taken to refer to human 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 term zootomy 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 in plant anatomy.

Animal tissues
The kingdom Animalia contains multicellular organisms that are heterotrophic and motile (although some have secondarily adopted a sessile lifestyle). Most animals have bodies differentiated into separate tissues and these animals are also known as eumetazoans. They have an internal digestive chamber, with one or two openings; the gametes are produced in multicellular sex organs, and the zygotes include a blastula stage in their embryonic development. Metazoans do not include the sponges, which have undifferentiated cells.

Unlike plant cells, animal cells have neither a cell wall nor chloroplasts. 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 of phospholipids, cytoplasm and a nucleus. All of the different cells of an animal are derived from the embryonic germ layers. Those simpler invertebrates which are formed from two germ layers of ectoderm and endoderm are called diploblastic and the more developed animals whose structures and organs are formed from three germ layers are called triploblastic. All of a triploblastic animal's tissues and organs are derived from the three germ layers of the embryo, the ectoderm, mesoderm and endoderm.

Animal tissues can be grouped into four basic types: connective, epithelial, muscle and nervous tissue.

Connective tissue
Connective tissues are fibrous and made up of cells scattered among inorganic material called the extracellular matrix. Often called fascia (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 contains proteins, the chief and most abundant of which is collagen. 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. An exoskeleton is a thickened, rigid cuticle which is stiffened by mineralization, as in crustaceans or by the cross-linking of its proteins as in insects. An endoskeleton is internal and present in all developed animals, as well as in many of those less developed.

Epithelium
Epithelial tissue is composed of closely packed cells, bound to each other by cell adhesion molecules, with little intercellular space. Epithelial cells can be squamous (flat), cuboidal or columnar and rest on a basal lamina, the upper layer of the basement membrane, the lower layer is the reticular lamina lying next to the connective tissue in the extracellular matrix secreted by the epithelial cells. There are many different types of epithelium, modified to suit a particular function. In the respiratory tract there is a type of ciliated epithelial lining; in the small intestine there are microvilli on the epithelial lining and in the large intestine there are intestinal villi. Skin consists of an outer layer of keratinized stratified squamous epithelium that covers the exterior of the vertebrate body. Keratinocytes make up to 95% of the cells in the skin. The epithelial cells on the external surface of the body typically secrete an extracellular matrix in the form of a cuticle. In simple animals this may just be a coat of glycoproteins. In more advanced animals, many glands are formed of epithelial cells.

Muscle tissue
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 contractile filaments and is separated into three main types; smooth muscle, skeletal muscle and cardiac muscle. Smooth muscle has no striations when examined microscopically. It contracts slowly but maintains contractibility over a wide range of stretch lengths. It is found in such organs as sea anemone tentacles and the body wall of sea 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 in earthworms that can extend slowly or make rapid contractions. 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 the uterus, bladder, intestines, stomach, oesophagus, respiratory airways, and blood vessels. Cardiac muscle is found only in the heart, allowing it to contract and pump blood round the body.

Nervous tissue
Nervous tissue is composed of many nerve cells known as neurons which transmit information. In some slow-moving radially symmetrical marine animals such as ctenophores and cnidarians (including sea anemones and jellyfish), the nerves form a nerve net, but in most animals they are organized longitudinally into bundles. In simple animals, receptor neurons in the body wall cause a local reaction to a stimulus. In more complex animals, specialized receptor cells such as chemoreceptors and photoreceptors are found in groups and send messages along neural networks to other parts of the organism. Neurons can be connected together in ganglia. In higher animals, specialized receptors are the basis of sense organs and there is a central nervous system (brain and spinal cord) and a peripheral nervous system. The latter consists of sensory nerves that transmit information from sense organs and motor nerves that influence target organs. The peripheral nervous system is divided into the somatic nervous system which conveys sensation and controls voluntary muscle, and the autonomic nervous system which involuntarily controls smooth muscle, certain glands and internal organs, including the stomach.

Vertebrate anatomy
All vertebrates have a similar basic body plan and at some point in their lives, mostly in the embryonic stage, share the major chordate characteristics: a stiffening rod, the notochord; a dorsal hollow tube of nervous material, the neural tube; pharyngeal arches; and a tail posterior to the anus. The spinal cord is protected by the vertebral column and is above the notochord, and the gastrointestinal tract is below it. Nervous tissue is derived from the ectoderm, connective tissues are derived from mesoderm, and gut is derived from the endoderm. 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 the anus at the base of the tail. The defining characteristic of a vertebrate is the vertebral column, formed in the development of the segmented series of vertebrae. In most vertebrates the notochord becomes the nucleus pulposus of the intervertebral discs. However, a few vertebrates, such as the sturgeon and the coelacanth, retain the notochord into adulthood. Jawed vertebrates are typified by paired appendages, fins or legs, which may be secondarily lost. The limbs of vertebrates are considered to be homologous because the same underlying skeletal structure was inherited from their last common ancestor. This is one of the arguments put forward by Charles Darwin to support his theory of evolution.

Fish anatomy
The body of a fish 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, in cartilaginous fish, or bone in bony fish. The main skeletal element is the vertebral column, composed of articulating vertebrae which are lightweight yet strong. The ribs attach to the spine and there are no limbs or limb girdles. The main external features of the fish, the fins, are composed of either bony or soft spines called rays, which with the exception of the caudal fins, have no direct connection with the spine. They are supported by the muscles which compose the main part of the trunk. The heart has two chambers and pumps the blood through the respiratory surfaces of the gills and on round the body in a single circulatory loop. The eyes are adapted for seeing underwater and have only local vision. There is an inner ear but no external or middle ear. Low frequency vibrations are detected by the lateral 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.

Sharks and rays are basal fish with numerous primitive 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 dermal placoid scales. They have a cloaca into which the urinary and genital passages open, but not a swim bladder. Cartilaginous fish produce a small number of large, yolky eggs. Some species are ovoviviparous and the young develop internally but others are oviparous and the larvae develop externally in egg cases.

The bony fish lineage shows more derived 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 an operculum, and a mouth at or near the tip of the snout. The dermis is covered with overlapping scales. Bony fish have a swim bladder which helps them maintain a constant depth in the water column, but not a cloaca. They mostly spawn a large number of small eggs with little yolk which they broadcast into the water column.

Amphibian anatomy
Amphibians are a class of animals comprising frogs, salamanders and caecilians. They are tetrapods, 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 have articular 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 little keratin and lacks scales, but contains many mucous glands and in some species, poison glands. The hearts of amphibians have three chambers, two atria and one ventricle. They have a urinary bladder and nitrogenous waste products are excreted primarily as urea. Amphibians breathe by means of buccal pumping, a pump action in which air is first drawn into the buccopharyngeal region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat. They supplement this with gas exchange through the skin which needs to be kept moist.

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 resemble earthworms 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.

Reptile anatomy
Reptiles are a class of animals comprising turtles, tuataras, lizards, snakes and crocodiles. They are tetrapods, 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 their lungs 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 a copulatory organ present in most species. The eggs are surrounded by amniotic membranes which prevents them from drying out and are laid on land, or develop internally in some species. The bladder is small as nitrogenous waste is excreted as uric acid.

Turtles are notable for their protective shells. They have an inflexible trunk encased in a horny carapace above and a plastron 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.

Tuataras superficially resemble lizards but the lineages diverged in the Triassic 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 lack bronchi. The tuatara has a well-developed parietal eye on its forehead.

Lizards have skulls with only one fenestra 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.

Snakes are closely related to lizards, having branched off from a common ancestral lineage during the Cretaceous 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 of pelvic 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.

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.

Bird anatomy
Birds are tetrapods but though their hind limbs are used for walking or hopping, their front limbs are wings covered with feathers and adapted for flight. Birds are endothermic, have a high metabolic rate, a light skeletal system and powerful muscles. 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.

The feathers are outgrowths of the epidermis 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 single uropygial gland near the base of the tail. This produces an oily secretion that waterproofs the feathers when the bird preens. There are scales on the legs, feet and claws on the tips of the toes.

Mammal anatomy
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 of prismatic enamel. The teeth are shed once (milk teeth) during the animal's lifetime or not at all, as is the case in cetaceans. Mammals have three bones in the middle ear and a cochlea in the inner ear. They are clothed in hair and their skin contains glands which secrete sweat. Some of these glands are specialized as mammary glands, producing milk to feed the young. Mammals breathe with lungs and have a muscular diaphragm 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.

Mammals are amniotes, and most are viviparous, giving birth to live young. Exceptions to this are the egg-laying monotremes, the platypus and the echidnas of Australia. Most other mammals have a placenta through which the developing foetus obtains nourishment, but in marsupials, the foetal stage is very short and the immature young is born and finds its way to its mother's pouch where it latches on to a nipple and completes its development.

Human anatomy
Humans have the overall body plan of a mammal. Humans have a head, neck, trunk (which includes the thorax and abdomen), two arms and hands, and two legs and feet.

Generally, students of certain biological sciences, paramedics, prosthetists and orthotists, physiotherapists, occupational therapists, nurses, podiatrists, and medical 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 of dissection and inspection of cadavers. The study of microscopic anatomy (or histology) can be aided by practical experience examining histological preparations (or slides) under a microscope.

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. The major anatomy textbook, Gray's Anatomy, has been reorganized from a systems format to a regional format, in line with modern teaching methods. A thorough working knowledge of anatomy is required by physicians, especially surgeons and doctors working in some diagnostic specialties, such as histopathology and radiology.

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.

Invertebrate anatomy
Invertebrates constitute a vast array of living organisms ranging from the simplest unicellular eukaryotes such as Paramecium to such complex multicellular animals as the octopus, lobster and dragonfly. They constitute about 95% of the animal species. By definition, none of these creatures has a backbone. The cells of single-cell protozoans 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 by cilia or flagella or may proceed via the advance of pseudopodia, food may be gathered by phagocytosis, energy needs may be supplied by photosynthesis and the cell may be supported by an endoskeleton or an exoskeleton. Some protozoans can form multicellular colonies.

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 an extracellular matrix which provides support to the organism. An endoskeleton derived from the mesoderm is present in echinoderms, sponges and some cephalopods. Exoskeletons are derived from the epidermis and is composed of chitin in arthropods (insects, spiders, ticks, shrimps, crabs, lobsters). Calcium carbonate constitutes the shells of molluscs, brachiopods and some tube-building polychaete worms and silica forms the exoskeleton of the microscopic diatoms and radiolaria. Other invertebrates may have no rigid structures but the epidermis may secrete a variety of surface coatings such as the pinacoderm of sponges, the gelatinous cuticle of cnidarians (polyps, sea anemones, jellyfish) and the collagenous cuticle of annelids. The outer epithelial layer may include cells of several types including sensory cells, gland cells and stinging cells. There may also be protrusions such as microvilli, cilia, bristles, spines and tubercles.

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.

Arthropod anatomy
Arthropods comprise the largest phylum of invertebrates in the animal kingdom with over a million known species.

Insects possess segmented bodies supported by a hard-jointed outer covering, the exoskeleton, made mostly of chitin. The segments of the body are organized into three distinct parts, a head, a thorax and an abdomen. The head typically bears a pair of sensory antennae, a pair of compound eyes, one to three simple eyes (ocelli) and three sets of modified appendages that form the mouthparts. The thorax has three pairs of segmented legs, one pair each for the three segments that compose the thorax and one or two pairs of wings. The abdomen is composed of eleven segments, some of which may be fused and houses the digestive, respiratory, excretory and reproductive systems. There is considerable variation between species and many adaptations to the body parts, especially wings, legs, antennae and mouthparts.

Spiders a class of arachnids have four pairs of legs; a body of two segments—a cephalothorax and an abdomen. Spiders have no wings and no antennae. They have mouthparts called chelicerae which are often connected to venom glands as most spiders are venomous. They have a second pair of appendages called pedipalps 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 the copulatory organ.

Other branches of anatomy

 * Surface anatomy is important as the study of anatomical landmarks that can be readily seen from the exterior contours of the body. It enables medics and veterinarians 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.
 * Comparative anatomy relates to the comparison of anatomical structures (both gross and microscopic) in different animals.
 * Artistic anatomy relates to anatomic studies of body proportions for artistic reasons.

Ancient

In 1600 BCE, the Edwin Smith Papyrus, an Ancient Egyptian medical text, described the heart and its vessels, as well as the brain and its meninges and cerebrospinal fluid, and the liver, spleen, kidneys, uterus and bladder, and it showed the blood vessels diverging from the heart. The Ebers Papyrus (c. 1550 BCE) features a "treatise on the heart", with vessels carrying all the body's fluids to or from every member of the body.

Ancient Greek anatomy and physiology underwent great changes and advances throughout the early medieval world. Over time, this medical practice expanded by a continually developing understanding of the functions of organs and structures in the body. Phenomenal anatomical observations of the human body were made, which have contributed towards the understanding of the brain, eye, liver, reproductive organs and the nervous system.

The Hellenistic Egyptian city of Alexandria 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 the Ptolemaic dynasty of Egypt helped raise Alexandria up, further rivalling the cultural and scientific achievements of other Greek states.

Some of the most striking advances in early anatomy and physiology took place in Hellenistic Alexandria. Two of the most famous anatomists and physiologists of the third century were Herophilus and Erasistratus. These two physicians helped pioneer human dissection 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. Herophilus became known for his anatomical works making impressing contributions to many branches of anatomy and many other aspects of medicine. 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 disease. Erasistratus accurately described the structure of the brain, including the cavities and membranes, and made a distinction between its cerebrum and cerebellum During his study in Alexandria, Erasistratus was particularly concerned with studies of the circulatory and nervous systems. He was able to distinguish the sensory and the motor nerves in the human body and believed that 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 carried 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 valves of the heart, including the tricuspid. During the third century, Greek physicians were able to differentiate nerves from blood vessels and tendons and to realize that the nerves convey neural impulses. It was Herophilus who made the point that damage to motor nerves induced paralysis. 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 Herophilus is also credited with describing the optic, oculomotor, motor division of the trigeminal, facial, vestibulocochlear and hypoglossal nerves.

Great feats were made during the third century BCE in both the digestive and reproductive systems. Herophilus was able to discover and describe not only the salivary glands, but the small intestine and liver. 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.

The anatomy of the muscles and skeleton is described in the Hippocratic Corpus, an Ancient Greek medical work written by unknown authors. Aristotle described vertebrate anatomy based on animal dissection. Praxagoras identified the difference between arteries and veins. Also in the 4th century BCE, Herophilos and Erasistratus produced more accurate anatomical descriptions based on vivisection of criminals in Alexandria during the Ptolemaic period.

In the 2nd century, Galen of Pergamum, an anatomist, clinician, writer and philosopher, wrote the final and highly influential anatomy treatise of ancient times. He compiled existing knowledge and studied anatomy through dissection of animals. He was one of the first experimental physiologists through his vivisection experiments on animals. Galen's drawings, based mostly on dog anatomy, became effectively the only anatomical textbook for the next thousand years. His work was known to Renaissance doctors only through Islamic Golden Age medicine until it was translated from the Greek some time in the 15th century.

Medieval to early modern

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". Between 1275 and 1326, the anatomists Mondino de Luzzi, Alessandro Achillini and Antonio Benivieni at Bologna carried out the first systematic human dissections since ancient times. Mondino's Anatomy 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, then the thorax, then the head and limbs. It was the standard anatomy textbook for the next century.

Leonardo da Vinci (1452–1519) was trained in anatomy by Andrea del Verrocchio. 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.

Andreas Vesalius (1514–1564), professor of anatomy at the University of Padua, is considered the founder of modern human anatomy. Originally from Brabant, Vesalius published the influential book De humani corporis fabrica ("the structure of the human body"), a large format book in seven volumes, in 1543. The accurate and intricately detailed illustrations, often in allegorical poses against Italianate landscapes, are thought to have been made by the artist Jan van Calcar, a pupil of Titian.

In England, anatomy was the subject of the first public lectures given in any science; these were given by the Company of Barbers and Surgeons in the 16th century, joined in 1583 by the Lumleian lectures in surgery at the Royal College of Physicians.

Late modern
In the United States, medical schools began to be set up 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 for body snatching activity as criminals raided graveyards at night, removing newly buried corpses from their coffins. A similar problem existed in Britain where demand for bodies became so great that grave-raiding and even anatomy murder were practised to obtain cadavers. Some graveyards were in consequence protected with watchtowers. The practice was halted in Britain by the Anatomy Act of 1832, while in the United States, similar legislation was enacted after the physician William S. Forbes of Jefferson Medical College was found guilty in 1882 of "complicity with resurrectionists in the despoliation of graves in Lebanon Cemetery".

The teaching of anatomy in Britain was transformed by Sir John Struthers, Regius Professor of Anatomy at the University 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 of comparative anatomy, published over 70 research papers, and became famous for his public dissection of the Tay Whale. From 1822 the Royal College of Surgeons regulated the teaching of anatomy in medical schools. Medical museums provided examples in comparative anatomy, and were often used in teaching. Ignaz Semmelweis investigated puerperal 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. Before the modern medical era, the main means for studying the internal structures of the body were dissection of the dead and inspection, palpation and auscultation of the living. It was the advent of microscopy that opened up an understanding of the building blocks that constituted living tissues. Technical advances in the development of achromatic lenses increased the resolving power of the microscope and around 1839, Matthias Jakob Schleiden and Theodor Schwann identified that cells were the fundamental unit of organization of all living things. Study of small structures involved passing light through them and the microtome was invented to provide sufficiently thin slices of tissue to examine. Staining techniques using artificial dyes were established to help distinguish between different types of tissue. Advances in the fields of histology and cytology began in the late 19th century along with advances in surgical techniques allowing for the painless and safe removal of biopsy specimens. The invention of the electron microscope brought a great advance in resolution power and allowed research into the ultrastructure of cells and the organelles and other structures within them. About the same time, in the 1950s, the use of X-ray diffraction for studying the crystal structures of proteins, nucleic acids and other biological molecules gave rise to a new field of molecular anatomy.

Equally important advances have occurred in non-invasive techniques for examining the interior structures of the body. X-rays can be passed through the body and used in medical radiography and fluoroscopy to differentiate interior structures that have varying degrees of opaqueness. Magnetic resonance imaging, computed tomography, and ultrasound imaging have all enabled examination of internal structures in unprecedented detail to a degree far beyond the imagination of earlier generations.

title: Anatomy


text:
Affirming the consequent

In propositional logic, affirming the consequent, sometimes called converse error, fallacy of the converse, or confusion of necessity and sufficiency, is a formal fallacy of taking a true conditional statement (e.g., "if the lamp were broken, then the room would be dark") under certain assumptions (there are no other lights in the room, it is nighttime and the windows are closed), and invalidly inferring its converse ("the room is dark, so the lamp must be broken"), even though that statement may not be true under the same assumptions. This arises when the consequent ("the room would be dark") has other possible antecedents (for example, "the lamp is in working order, but is switched off" or "there is no lamp in the room").

Converse errors are common in everyday thinking and communication and can result from, among other causes, communication issues, misconceptions about logic, and failure to consider other causes.

The opposite statement, denying the consequent, is called modus tollens and is a valid form of argument.

Formal description

Affirming the consequent is the action of taking a true statement $$P \to Q$$ and invalidly concluding its converse $$Q \to P$$. The name affirming the consequent derives from using the consequent, Q, of $$P \to Q$$, to conclude the antecedent P. This fallacy can be summarized formally as $$(P \to Q, Q)\to P$$ or, alternatively, $$\frac{P \to Q, Q}{\therefore P}$$. The root cause of such a logical error is sometimes failure to realize that just because P is a possible condition for Q, P may not be the only condition for Q, i.e. Q may follow from another condition as well.

Affirming the consequent can also result from overgeneralizing the experience of many statements having true converses. If P and Q are "equivalent" statements, i.e. $$P \leftrightarrow Q$$, it is possible to infer P under the condition Q. For example, the statements "It is August 13, so it is my birthday" $$P \to Q$$ and "It is my birthday, so it is August 13" $$Q \to P$$ are equivalent and both true consequences of the statement "August 13 is my birthday" (an abbreviated form of $$P \leftrightarrow Q$$).

Of the possible forms of "mixed hypothetical syllogisms," two are valid and two are invalid. Affirming the antecedent (modus ponens) and denying the consequent (modus tollens) are valid. Affirming the consequent and denying the antecedent are invalid.

Additional examples
Example 1

One way to demonstrate the invalidity of this argument form is with a counterexample with true premises but an obviously false conclusion. For example:

 * If someone lives in San Diego, then they live in California.
 * Joe lives in California.
 * Therefore, Joe lives in San Diego.

There are many places to live in California other than San Diego. On the other hand, one can affirm with certainty that "if someone does not live in California" (non-Q), then "this person does not live in San Diego" (non-P). This is the contrapositive of the first statement, and it must be true if and only if the original statement is true.

Example 2

 * If an animal is a dog, then it has four legs.
 * My cat has four legs.
 * Therefore, my cat is a dog.

Here, it is immediately intuitive that any number of other antecedents ("If an animal is a deer...", "If an animal is an elephant...", "If an animal is a moose...", etc.) can give rise to the consequent ("then it has four legs"), and that it is preposterous to suppose that having four legs must imply that the animal is a dog and nothing else. This is useful as a teaching example since most people can immediately recognize that the conclusion reached must be wrong (intuitively, a cat cannot be a dog), and that the method by which it was reached must therefore be fallacious.

Example 3

In Catch-22, the chaplain is interrogated for supposedly being "Washington Irving"/"Irving Washington", who has been blocking out large portions of soldiers' letters home. The colonel has found such a letter, but with the Chaplain's name signed.

 * "You can read, though, can't you?" the colonel persevered sarcastically. "The author signed his name."
 * "That's my name there."
 * "Then you wrote it. Q.E.D."

P in this case is 'The chaplain signs his own name', and Q 'The chaplain's name is written'. The chaplain's name may be written, but he did not necessarily write it, as the colonel falsely concludes.''

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Affirming the consequent


text:
Andrei Tarkovsky

Andrei Arsenyevich Tarkovsky (Андрей Арсеньевич Тарковский  4 April 1932 – 29 December 1986) was a Soviet film director and screenwriter of Russian origin. Widely considered one of the greatest and most influential directors in cinema history, Tarkovsky's films explore spiritual and metaphysical themes, and are noted for their slow pacing and long takes, dreamlike visual imagery, and preoccupation with nature and memory.

Tarkovsky studied film at Moscow's VGIK under filmmaker Mikhail Romm, and subsequently directed his first five features in the Soviet Union: Ivan's Childhood (1962), Andrei Rublev (1966), Solaris (1972), Mirror (1975), and Stalker (1979). A number of his films from this period are ranked among the best films ever made. After years of creative conflict with state film authorities, Tarkovsky left the country in 1979 and made his final two films abroad; Nostalghia (1983) and The Sacrifice (1986) were produced in Italy and Sweden respectively. In 1986, he also published a book about cinema and art entitled Sculpting in Time. He died later that year of cancer, a condition possibly caused by the toxic locations used in the filming of Stalker.

Tarkovsky was the recipient of several awards at the Cannes Film Festival throughout his career, including the FIPRESCI prize, the Prize of the Ecumenical Jury, and the Grand Prix Spécial du Jury. He was also awarded the Golden Lion at the Venice Film Festival for his debut film, Ivan's Childhood. In 1990, he was posthumously awarded the Soviet Union's prestigious Lenin Prize. Three of his films—Andrei Rublev, Mirror, and Stalker—featured in Sight & Sound 2012 poll of the 100 greatest films of all time.

Childhood and early life
Andrei Tarkovsky was born in the village of Zavrazhye in the Yuryevetsky District of the Ivanovo Industrial Oblast (modern-day Kadyysky District of the Kostroma Oblast, Russia) to the poet and translator Arseny Aleksandrovich Tarkovsky, a native of Yelysavethrad (now Kropyvnytskyi, Ukraine), and Maria Ivanova Vishnyakova, a graduate of the Maxim Gorky Literature Institute who later worked as a proofreader; she was born in Moscow in the Dubasov family estate.

Andrei's paternal grandfather Aleksandr Karlovich Tarkovsky (in Aleksander Karol Tarkowski) was a Polish nobleman who worked as a bank clerk. His wife Maria Danilovna Rachkovskaya was a Romanian language teacher who arrived from Iași. Andrei's maternal grandmother Vera Nikolayevna Vishnyakova (née Dubasova) belonged to an old Dubasov family of Russian nobility that traces its history back to the 17th century; among her relatives was Admiral Fyodor Dubasov, a fact she had to conceal during the Soviet days. She was married to Ivan Ivanovich Vishnyakov, a native of the Kaluga Governorate who studied law at the Moscow State University and served as a judge in Kozelsk.

According to the family legend, Tarkovsky's ancestors on his father's side were princes from the Shamkhalate of Tarki, Dagestan, although his sister, Marina Tarkovskaya, who conducted detailed research on their genealogy, called it "a myth, even a prank of sorts," stressing that no document confirms this narrative.

Tarkovsky spent his childhood in Yuryevets. He was described by childhood friends as active and popular, having many friends and being typically in the center of action. His father left the family in 1937, subsequently volunteering for the army in 1941. He returned home in 1943, having been awarded a Red Star after being shot in one of his legs (which he would eventually need to amputate due to gangrene). Tarkovsky stayed with his mother, moving with her and his sister Marina to Moscow, where she worked as a proofreader at a printing press.

In 1939, Tarkovsky enrolled at the Moscow School No. 554. During the war, the three evacuated to Yuryevets, living with his maternal grandmother. In 1943, the family returned to Moscow. Tarkovsky continued his studies at his old school, where the poet Andrei Voznesensky was one of his classmates. He studied piano at a music school and attended classes at an art school. The family lived on Shchipok Street in the Zamoskvorechye District in Moscow. From November 1947 to spring 1948 he was in the hospital with tuberculosis. Many themes of his childhood—the evacuation, his mother and her two children, the withdrawn father, the time in the hospital—feature prominently in his film Mirror.

In his school years, Tarkovsky was a troublemaker and a poor student. He still managed to graduate, and from 1951 to 1952 studied Arabic at the Oriental Institute in Moscow, a branch of the Academy of Sciences of the Soviet Union. Although he already spoke some Arabic and was a successful student in his first semesters, he did not finish his studies and dropped out to work as a prospector for the Academy of Science Institute for Non-Ferrous Metals and Gold. He participated in a year-long research expedition to the river Kureyka near Turukhansk in the Krasnoyarsk Province. During this time in the taiga, Tarkovsky decided to study film.

Film school student
Upon returning from the research expedition in 1954, Tarkovsky applied at the State Institute of Cinematography (VGIK) and was admitted to the film-directing program. He was in the same class as Irma Raush (Irina) whom he married in April 1957.

The early Khrushchev era offered good opportunities for young film directors. Before 1953, annual film production was low and most films were directed by veteran directors. After 1953, more films were produced, many of them by young directors. The Khrushchev Thaw relaxed Soviet social restrictions a bit and permitted a limited influx of European and North American literature, films and music. This allowed Tarkovsky to see films of the Italian neorealists, French New Wave, and of directors such as Kurosawa, Buñuel, Bergman, Bresson, Wajda (whose film Ashes and Diamonds influenced Tarkovsky) and Mizoguchi.

Tarkovsky's teacher and mentor was Mikhail Romm, who taught many film students who would later become influential film directors. In 1956, Tarkovsky directed his first student short film, The Killers, from a short story of Ernest Hemingway. The longer television film There Will Be No Leave Today followed in 1959. Both films were a collaboration between the VGIK students. Classmate Aleksandr Gordon, who married Tarkovsky's sister, in particular directed, wrote, edited, and acted in the two films with Tarkovsky.

An important influence on Tarkovsky was the film director Grigory Chukhray, who was teaching at the VGIK. Impressed by the talent of his student, Chukhray offered Tarkovsky a position as assistant director for his film Clear Skies. Tarkovsky initially showed interest but then decided to concentrate on his studies and his own projects.

During his third year at the VGIK, Tarkovsky met Andrei Konchalovsky. They found much in common as they liked the same film directors and shared ideas on cinema and films. In 1959, they wrote the script Antarctica – Distant Country, which was later published in the Moskovsky Komsomolets. Tarkovsky submitted the script to Lenfilm, but it was rejected. They were more successful with the script The Steamroller and the Violin, which they sold to Mosfilm. This became Tarkovsky's graduation project, earning him his diploma in 1960 and winning First Prize at the New York Student Film Festival in 1961.

Film career in the Soviet Union
Tarkovsky's first feature film was Ivan's Childhood in 1962. He had inherited the film from director Eduard Abalov, who had to abort the project. The film earned Tarkovsky international acclaim and won the Golden Lion award at the Venice Film Festival in the year 1962. In the same year, on 30 September, his first son Arseny (called Senka in Tarkovsky's diaries) Tarkovsky was born. In 1965, he directed the film Andrei Rublev about the life of Andrei Rublev, the fifteenth-century Russian icon painter. Andrei Rublev was not, except for a single screening in Moscow in 1966, immediately released after completion due to problems with Soviet authorities. Tarkovsky had to cut the film several times, resulting in several different versions of varying lengths. The film was widely released in the Soviet Union in a cut version in 1971. Nevertheless, the film had a budget of more than 1 million rubles – a significant sum for that period. A version of the film was presented at the Cannes Film Festival in 1969 and won the FIPRESCI prize.

He divorced his wife, Irina, in June 1970. In the same year, he married Larisa Kizilova (née Egorkina), who had been a production assistant for the film Andrei Rublev (they had been living together since 1965). Their son, Andrei Andreyevich Tarkovsky, (nicknamed Andriosha, meaning "little Andre" or "Andre Junior") was born in the same year on 7 August.

In 1972, he completed Solaris, an adaptation of the novel Solaris by Stanisław Lem. He had worked on this together with screenwriter Friedrich Gorenstein as early as 1968. The film was presented at the Cannes Film Festival, won the Grand Prix Spécial du Jury, and was nominated for the Palme d'Or.

From 1973 to 1974, he shot the film Mirror, a highly autobiographical and unconventionally structured film drawing on his childhood and incorporating some of his father's poems. In this film Tarkovsky portrayed the plight of childhood affected by war. Tarkovsky had worked on the screenplay for this film since 1967, under the consecutive titles Confession, White day and A white, white day. From the beginning the film was not well received by Soviet authorities due to its content and its perceived elitist nature. Soviet authorities placed the film in the "third category", a severely limited distribution, and only allowed it to be shown in third-class cinemas and workers' clubs. Few prints were made and the film-makers received no returns. Third category films also placed the film-makers in danger of being accused of wasting public funds, which could have serious effects on their future productivity. These difficulties are presumed to have made Tarkovsky play with the idea of going abroad and producing a film outside the Soviet film industry.

During 1975, Tarkovsky also worked on the screenplay Hoffmanniana, about the German writer and poet E. T. A. Hoffmann. In December 1976, he directed Hamlet, his only stage play, at the Lenkom Theatre in Moscow. The main role was played by Anatoly Solonitsyn, who also acted in several of Tarkovsky's films. At the end of 1978, he also wrote the screenplay Sardor together with the writer Aleksandr Misharin.

The last film Tarkovsky completed in the Soviet Union was Stalker, inspired by the novel Roadside Picnic by the brothers Arkady and Boris Strugatsky. Tarkovsky had met the brothers first in 1971 and was in contact with them until his death in 1986. Initially he wanted to shoot a film based on their novel Dead Mountaineer's Hotel and he developed a raw script. Influenced by a discussion with Arkady Strugatsky he changed his plan and began to work on the script based on Roadside Picnic. Work on this film began in 1976. The production was mired in troubles; improper development of the negatives had ruined all the exterior shots. Tarkovsky's relationship with cinematographer Georgy Rerberg deteriorated to the point where he hired Alexander Knyazhinsky as a new first cinematographer. Furthermore, Tarkovsky had a heart attack in April 1978, resulting in further delay. The film was completed in 1979 and won the Prize of the Ecumenical Jury at the Cannes Film Festival. In a question and answer session at the Edinburgh Filmhouse on 11 February 1981, Tarkovsky trenchantly rejected suggestions that the film was either impenetrably mysterious or a political allegory.

In 1979, Tarkovsky began production of the film The First Day (Russian: Первый День Pervyj Dyen), based on a script by his friend and long-term collaborator Andrei Konchalovsky. The film was set in 18th-century Russia during the reign of Peter the Great and starred Natalya Bondarchuk and Anatoli Papanov. To get the project approved by Goskino, Tarkovsky submitted a script that was different from the original script, omitting several scenes that were critical of the official atheism in the Soviet Union. After shooting roughly half of the film the project was stopped by Goskino after it became apparent that the film differed from the script submitted to the censors. Tarkovsky was reportedly infuriated by this interruption and destroyed most of the film.

Film career outside the Soviet Union
During the summer of 1979, Tarkovsky traveled to Italy, where he shot the documentary Voyage in Time together with his long-time friend Tonino Guerra. Tarkovsky returned to Italy in 1980 for an extended trip, during which he and Guerra completed the script for the film Nostalghia. During this period, he took Polaroid photographs depicting his personal life.

Tarkovsky returned to Italy in 1982 to start shooting Nostalghia, but Mosfilm then withdrew from the project, so he sought and received financial backing from the Italian RAI. Tarkovsky completed the film in 1983, and it was presented at the Cannes Film Festival where it won the FIPRESCI prize and the Prize of the Ecumenical Jury. Tarkovsky also shared a special prize called Grand Prix du cinéma de création with Robert Bresson. Soviet authorities lobbied to prevent the film from winning the Palme d'Or, a fact that hardened Tarkovsky's resolve to never work in the Soviet Union again. After Cannes he went to London to stage and choreograph the opera Boris Godunov at the Royal Opera House under the musical direction of Claudio Abbado.

At a press conference in Milan on 10 July 1984, he announced that he would never return to the Soviet Union and would remain in Western Europe. He stated, "I am not a Soviet dissident, I have no conflict with the Soviet Government," but if he returned home, he added, "I would be unemployed." At that time, his son Andriosha was still in the Soviet Union and not allowed to leave the country. On 28 August 1985, Tarkovsky was processed as a Soviet Defector at a refugee camp in Latina, Italy, registered with the serial number 13225/379, and officially welcomed to the West.

Tarkovsky spent most of 1984 preparing the film The Sacrifice. It was finally shot in 1985 in Sweden, with many of the crew being alumni from Ingmar Bergman's films, including cinematographer Sven Nykvist. Tarkovsky's vision of his film was greatly influenced by Bergman's style.

While The Sacrifice is about an apocalypse and impending death, faith, and possible redemption, in the making-of documentary Directed by Andrei Tarkovsky, in a particularly poignant scene, writer/director Michal Leszczylowski follows Tarkovsky on a walk as he expresses his sentiments on death—he claims himself to be immortal and has no fear of dying. Ironically, at the end of the year Tarkovsky was diagnosed with terminal lung cancer. In January 1986, he began treatment in Paris and was joined there by his son, Andre Jr, who was finally allowed to leave the Soviet Union. What would be Tarkovsky's final film was dedicated to him.

The Sacrifice was presented at the Cannes Film Festival and received the Grand Prix Spécial du Jury, the FIPRESCI prize and the Prize of the Ecumenical Jury. As Tarkovsky was unable to attend due to his illness, the prizes were collected by his son.

Death
In Tarkovsky's last diary entry (15 December 1986), he wrote: "But now I have no strength left—that is the problem". The diaries are sometimes also known as Martyrology and were published posthumously in 1989 and in English in 1991.

Tarkovsky died in Paris on 29 December 1986. His funeral ceremony was held at the Alexander Nevsky Cathedral. He was buried on 3 January 1987 in the Russian Cemetery in Sainte-Geneviève-des-Bois in France. The inscription on his gravestone, which was erected in 1994, was conceived by Tarkovsky's wife, Larisa, reads: To the man who saw the Angel. Larisa died in 1998 and is buried beside her husband.

A conspiracy theory emerged in Russia in the early 1990s when it was alleged that Tarkovsky did not die of natural causes, but was assassinated by the KGB. Evidence for this hypothesis includes testimonies by former KGB agents who claim that Viktor Chebrikov gave the order to eradicate Tarkovsky to curtail what the Soviet government and the KGB saw as anti-Soviet propaganda by Tarkovsky. Other evidence includes several memoranda that surfaced after the 1991 coup and the claim by one of Tarkovsky's doctors that his cancer could not have developed from a natural cause.

Tarkovsky, his wife Larisa, and actor Anatoly Solonitsyn all died from the same type of cancer. Vladimir Sharun, a sound designer for Stalker, was convinced that all three died due to exposure to chemicals released from a chemical plant upstream from where the film was shot.

Influences and thoughts on film
Tarkovsky became a film director during the mid and late 1950s, a period referred to as the Khrushchev Thaw, during which Soviet society opened to foreign films, literature and music, among other things. This allowed Tarkovsky to see films of European, American and Japanese directors, an experience that influenced his own film making. His teacher and mentor at the film school, Mikhail Romm, allowed his students considerable freedom and emphasized the independence of the film director.

Tarkovsky was, according to fellow student Shavkat Abdusalmov, fascinated by Japanese films. He was amazed by how every character on the screen is exceptional and how everyday events such as a Samurai cutting bread with his sword are elevated to something special and put into the limelight. Tarkovsky has also expressed interest in the art of Haiku and its ability to create "images in such a way that they mean nothing beyond themselves".

Tarkovsky was also a deeply religious Orthodox Christian, who believed great art should have a higher spiritual purpose. He was a perfectionist not given to humor or humility: his signature style was ponderous and literary, having many characters that pondered over religious themes and issues regarding faith.

Tarkovsky perceived that the art of cinema has only been truly mastered by very few filmmakers, stating in a 1970 interview with Naum Abramov that "they can be counted on the fingers of one hand". In 1972, Tarkovsky told film historian Leonid Kozlov his ten favorite films. The list is as follows: Diary of a Country Priest and Mouchette by Robert Bresson; Winter Light, Wild Strawberries, and Persona by Ingmar Bergman; Nazarín by Luis Buñuel; City Lights by Charlie Chaplin; Ugetsu by Kenji Mizoguchi; Seven Samurai by Akira Kurosawa, and Woman in the Dunes by Hiroshi Teshigahara. He also liked Pier Paolo Pasolini's film The Gospel According to St. Matthew. Among his favorite directors were Buñuel, Mizoguchi, Bergman, Bresson, Kurosawa, Michelangelo Antonioni, Jean Vigo, and Carl Theodor Dreyer.

With the exception of City Lights, the list does not contain any films of the early silent era. The reason is that Tarkovsky saw film as an art as only a relatively recent phenomenon, with the early film-making forming only a prelude. The list has also no films or directors from Tarkovsky's native Ukraine, although he rated Soviet directors such as Boris Barnet, Sergei Parajanov and Alexander Dovzhenko highly. He said of Dovzhenko's Earth: "I have lived a lot among very simple farmers and met extraordinary people. They spread calmness, had such tact, they conveyed a feeling of dignity and displayed wisdom that I have seldom come across on such a scale. Dovzhenko had obviously understood wherein the sense of life resides. [...] This trespassing of the border between nature and mankind is an ideal place for the existence of man. Dovzhenko understood this."

He was also not a fan of blockbusters or science fiction, largely dismissing the latter for its "comic book" trappings and vulgar commercialism. However, in notable exceptions Tarkovsky praised the James Cameron blockbuster film The Terminator, saying that its "vision of the future and the relation between man and its destiny is pushing the frontier of cinema as an art". He was critical of the "brutality and low acting skills", but was nevertheless impressed by the film. He equally liked George Lucas's Star Wars according to his son, Andrei A. Tarkovsky.

Cinematic style
In a 1962 interview, Tarkovsky argued: "All art, of course, is intellectual, but for me, all the arts, and cinema even more so, must above all be emotional and act upon the heart." His films are characterized by metaphysical themes, extremely long takes, and images often considered by critics to be of exceptional beauty. Recurring motifs are dreams, memory, childhood, running water accompanied by fire, rain indoors, reflections, levitation, and characters re-appearing in the foreground of long panning movements of the camera. He once said: "Juxtaposing a person with an environment that is boundless, collating him with a countless number of people passing by close to him and far away, relating a person to the whole world, that is the meaning of cinema."

Tarkovsky incorporated levitation scenes into several of his films, most notably Solaris. To him these scenes possess great power and are used for their photogenic value and magical inexplicability. Water, clouds, and reflections were used by him for their surreal beauty and photogenic value, as well as their symbolism, such as waves or the forms of brooks or running water. Bells and candles are also frequent symbols. These are symbols of film, sight and sound, and Tarkovsky's film frequently has themes of self-reflection.

Tarkovsky developed a theory of cinema that he called "sculpting in time". By this he meant that the unique characteristic of cinema as a medium was to take our experience of time and alter it. Unedited movie footage transcribes time in real time. By using long takes and few cuts in his films, he aimed to give the viewers a sense of time passing, time lost, and the relationship of one moment in time to another.

Up to, and including, his film Mirror, Tarkovsky focused his cinematic works on exploring this theory. After Mirror, he announced that he would focus his work on exploring the dramatic unities proposed by Aristotle: a concentrated action, happening in one place, within the span of a single day.

Several of Tarkovsky's films have color or black-and-white sequences. This first occurs in the otherwise monochrome Andrei Rublev, which features a color epilogue of Rublev's authentic religious icon paintings. All of his films afterwards contain monochrome, and in Stalker's case sepia sequences, while otherwise being in color. In 1966, in an interview conducted shortly after finishing Andrei Rublev, Tarkovsky dismissed color film as a "commercial gimmick" and cast doubt on the idea that contemporary films meaningfully use color. He claimed that in everyday life one does not consciously notice colors most of the time, and that color should therefore be used in film mainly to emphasize certain moments, but not all the time, as this distracts the viewer. To him, films in color were like moving paintings or photographs, which are too beautiful to be a realistic depiction of life.

Director Ingmar Bergman commented on Tarkovsky: "My discovery of Tarkovsky's first film was like a miracle. Suddenly, I found myself standing at the door of a room the keys of which had until then, never been given to me. It was a room I had always wanted to enter and where he was moving freely and fully at ease. I felt encountered and stimulated: someone was expressing what I had always wanted to say without knowing how. Tarkovsky is for me the greatest, the one who invented a new language, true to the nature of film, as it captures life as a reflection, life as a dream."

Contrarily, however, Bergman conceded the truth in the claim made by a critic who wrote that "with Autumn Sonata Bergman does Bergman", adding: "Tarkovsky began to make Tarkovsky films, and that Fellini began to make Fellini films [...] Buñuel nearly always made Buñuel films." This pastiche of one's own work has been derogatorily termed as "self-karaoke".

Vadim Yusov
Tarkovsky worked in close collaboration with cinematographer Vadim Yusov from 1958 to 1972, and much of the visual style of Tarkovsky's films can be attributed to this collaboration. Tarkovsky would spend two days preparing for Yusov to film a single long take, and due to the preparation, usually only a single take was needed.

Sven Nykvist
In his last film, The Sacrifice, Tarkovsky worked with cinematographer Sven Nykvist, who had worked on many films with director Ingmar Bergman. (Nykvist was not alone: several people involved in the production had previously collaborated with Bergman, notably lead actor Erland Josephson, who had also acted for Tarkovsky in Nostalghia.) Nykvist complained that Tarkovsky would frequently look through the camera and even direct actors through it, but ultimately stated that choosing to work with Tarkovsky was one of the best choices he had ever made.

Filmography
Tarkovsky is mainly known as a film director. During his career he directed seven feature films, as well as three shorts from his time at VGIK. His features are:
 * Ivan's Childhood (1962)
 * Andrei Rublev (1966)
 * Solaris (1972)
 * Mirror (1975)
 * Stalker (1979)
 * Nostalghia (1983)
 * The Sacrifice (1986)

He also wrote several screenplays. Furthermore, he directed the play Hamlet for the stage in Moscow, directed the opera Boris Godunov in London, and he directed a radio production of the short story Turnabout by William Faulkner. He also wrote Sculpting in Time, a book on film theory.

Tarkovsky's first feature film was Ivan's Childhood in 1962. He then directed Andrei Rublev in 1966, Solaris in 1972, Mirror in 1975 and Stalker in 1979. The documentary Voyage in Time was produced in Italy in 1982, as was Nostalghia in 1983. His last film The Sacrifice was produced in Sweden in 1986. Tarkovsky was personally involved in writing the screenplays for all his films, sometimes with a cowriter. Tarkovsky once said that a director who realizes somebody else's screenplay without being involved in it becomes a mere illustrator, resulting in dead and monotonous films.

Publications

 * Sculpting in Time. University of Texas Press, 1986. ISBN 0-292-77624-1.
 * Time Within Time: The Diaries 1970–1986. Seagull, 1989. ISBN 9780857424921. Translated by Kitty Hunter-Blair.
 * Collected Screenplays. London: Faber & Faber, 2003. ISBN 978-0571142668.
 * Instant Light, Tarkovsky Polaroids. London: Thames and Hudson, 2006. ISBN 9780500286142. A book of 60 photographs taken by Tarkovsky in Russia and Italy between 1979 and 1984. Edited by Italian photographer Giovanni Chiaramonte and Tarkovsky's son Andrey A. Tarkovsky.
 * Bright, bright day. Tarkovsky Foundation and White Space Gallery, 2008. A book of Polaroids edited by Stephen Gill. ISBN 978-0955739415. Edition of 3000 copies.
 * Tarkovsky: Films, Stills, Polaroids & Writings. London: Thames and Hudson, 2019. ISBN 978-0500022597.

Concentrate
Concentrate (Концентрат, Kontsentrat) is a never-filmed 1958 screenplay by Tarkovsky. The screenplay is based on Tarkovsky's year in the taiga as a member of a research expedition, prior to his enrollment in film school. It's about the leader of a geological expedition, who waits for the boat that brings back the concentrates collected by the expedition. The expedition is surrounded by mystery, and its purpose is a state secret.

Although some authors claim that the screenplay was filmed, according to Marina Tarkovskaya, Tarkovsky's sister (and wife of Aleksandr Gordon, a fellow student of Tarkovsky during his film school years) the screenplay was never filmed. Tarkovsky wrote the screenplay during his entrance examination at the State Institute of Cinematography (VGIK) in a single sitting. He earned the highest possible grade, "excellent" (отлично) for this work. In 1994, fragments of Concentrate were filmed and used in the documentary Andrei Tarkovsky's Taiga Summer by Marina Tarkovskaya and Aleksandr Gordon.

Hoffmanniana
Hoffmanniana (Гофманиана) is a never-filmed 1974 screenplay by Tarkovsky. The screenplay is based on the life and work of German author E. T. A. Hoffmann. In 1974, an acquaintance from Tallinnfilm approached Tarkovsky to write a screenplay on a German theme. Tarkovsky considered Thomas Mann and E. T. A. Hoffmann, and also thought about Ibsen's Peer Gynt. In the end Tarkovsky signed a contract for a script based on the life and work of Hoffmann. He planned to write the script during the summer of 1974 at his dacha. Writing was not without difficulty, less than a month before the deadline he had not written a single page. He finally finished the project in late 1974 and submitted the final script to Tallinnfilm in October.

Although the script was well received by the officials at Tallinnfilm, it was the consensus that no one but Tarkovsky would be able to direct it. The script was sent to Goskino in February 1976, and although approval was granted for proceeding with making the film, the screenplay was never realized. In 1984, during the time of his exile in the West, Tarkovsky revisited the screenplay and made a few changes. He also considered to finally direct a film based on the screenplay but ultimately dropped this idea.

Films about Tarkovsky

 * Voyage in Time (1983): documents the travels in Italy of Andrei Tarkovsky in preparation for the making of his film Nostalghia, co-directed with Tonino Guerra.
 * Tarkovsky: A Poet in the Cinema (1984): directed by Donatella Baglivo.
 * Moscow Elegy (1987), a documentary/homage to Tarkovsky by Aleksandr Sokurov.
 * Auf der Suche nach der verlorenen Zeit (1988): Andrej Tarkowskijs Exil und Tod. Documentary directed by Ebbo Demant. Germany.
 * One Day in the Life of Andrei Arsenevich (1999): French documentary film directed by Chris Marker.
 * Andrey (2006): a film by Nariné Mktchyan and Arsen Azatyan about Tarkovsky visited Armenia.
 * Tarkovsky: Time Within Time (2015): documentary by P. J. Letofsky.
 * Andrei Tarkovsky: A Cinema Prayer (2019): a poetic documentary by Tarkovsky's son Andrei A. Tarkovsky.

Awards and commemoration
Numerous awards were bestowed on Tarkovsky throughout his lifetime.
 * At the Venice Film Festival, the Golden Lion of the for Ivan's Childhood
 * Andrei tarkovsky stamp russia 2007.jpg the Cannes Film Festival, the FIPRESCI prize three times, the Prize of the Ecumenical Jury three times (more than any other director), the Grand Prix Spécial du Jury twice, and the Best Director award once. He was also nominated for the Palme d'Or three times.
 * In 1987, the BAFTA Award for Best Foreign Language Film of the British Academy of Film and Television Arts for The Sacrifice.

Under the influence of Glasnost and Perestroika, Tarkovsky was finally recognized in the Soviet Union in the Autumn of 1986, shortly before his death, by a retrospective of his films in Moscow. After his death, an entire issue of the film magazine Iskusstvo Kino was devoted to Tarkovsky. In their obituaries, the film committee of the Council of Ministers of the Soviet Union and the Union of Soviet Film Makers expressed their sorrow that Tarkovsky had to spend the last years of his life in exile.

Posthumously, he was awarded the Lenin Prize in 1990, one of the highest state honors in the Soviet Union. In 1989, the Andrei Tarkovsky Memorial Prize was established, with its first recipient being the Russian animator Yuri Norstein. In three consecutive events, the Moscow International Film Festival awarded the Andrei Tarkovsky Award in 1993, 1995, and 1997.

In 1996, the Andrei Tarkovsky Museum opened in Yuryevets, his childhood town. A minor planet, 3345 Tarkovskij, discovered by Soviet astronomer Lyudmila Karachkina in 1982, has been named after him.

Tarkovsky has been the subject of several documentaries. Most notable is the 1988 documentary Moscow Elegy, by Russian film director Alexander Sokurov. Sokurov's own work has been heavily influenced by Tarkovsky. The film consists mostly of narration over stock footage from Tarkovsky's films. Directed by Andrei Tarkovsky is a 1988 documentary film by Michal Leszczylowski, an editor of the film The Sacrifice. Film director Chris Marker produced the television documentary One Day in the Life of Andrei Arsenevich as an homage to Andrei Tarkovsky in 2000.

At the entrance to the Gerasimov Institute of Cinematography in Moscow, there is a monument that includes statues of Tarkovsky, Gennady Shpalikov and Vasily Shukshin.

Reception and legacy
Andrei Tarkovsky and his works have received praise from many filmmakers, critics and thinkers.

The Swedish filmmaker Ingmar Bergman was quoted as saying: "Tarkovsky for me is the greatest [of us all], the one who invented a new language, true to the nature of film, as it captures life as a reflection, life as a dream".

The Japanese filmmaker Akira Kurosawa remarked on Tarkovsky's films as saying: "His unusual sensitivity is both overwhelming and astounding. It almost reaches a pathological intensity. Probably there is no equal among film directors alive now." Kurosawa also commented: "I love all of Tarkovsky's films. I love his personality and all his works. Every cut from his films is a marvelous image in itself. But the finished image is nothing more than the imperfect accomplishment of his idea. His ideas are only realized in part. And he had to make do with it."

The Iranian filmmaker Abbas Kiarostami remarked that: "Tarkovsky's works separate me completely from physical life, and are the most spiritual films I have seen".

The Polish filmmaker Krzysztof Kieślowski commented that: "Andrei Tarkovsky was one of the greatest directors of recent years," and regarded Tarkovsky's film Ivan's Childhood as an influence on his own work.

The Turkish filmmaker Nuri Bilge Ceylan said that when he first discovered the films of Andrei Tarkovsky as a college student, unsure of what he wanted to do with his life, he was utterly baffled by the lauded Ukrainian master. He walked out of a screening of Solaris at the halfway point, and stopped a VHS tape of Mirror at a similar juncture. Today, he considers the latter to be the greatest film ever made. "I've seen it maybe 20 times," he says.

The Armenian filmmaker Sergei Parajanov remarked that watching Tarkovsky's film, Ivan's Childhood was his main inspiration to become a filmmaker by saying: "I did not know how to do anything and I would not have done anything if there had not been Ivan's Childhood".

The Austrian filmmaker Michael Haneke voted for Mirror on his top 10 films in the 2002 Sight & Sound directors' poll and later said that he has seen the picture at least 25 times.

The American filmmaker Stan Brakhage said that: "I personally think that the three greatest tasks for film in the 20th century are (1) To make the epic, that is to tell the tales of the tribes of the world. (2) To keep it personal, because only in the eccentricities of our personal lives do we have any chances at the truth. (3) To do the dream work, that is, to illuminate the borders of the unconscious. The only filmmaker I know that does all these three things equally in every film he makes is Andrei Tarkovsky, and that's why I think he's the greatest living narrative filmmaker."

The German filmmaker Wim Wenders dedicated his film Wings of Desire to Tarkovsky (along with François Truffaut and Yasujirō Ozu).

The French filmmaker Chris Marker directed a documentary film as a homage to Tarkovsky called One Day in the Life of Andrei Arsenevich and used Tarkovsky's concept of "The Zone" (from the film, Stalker) for his 1983 film essay, Sans Soleil.

The Greek filmmaker Theo Angelopoulos regarded Tarkovsky's film Stalker as one of the films that influenced him.

The Polish filmmaker Andrzej Żuławski remarked that: "If anybody influenced anybody, it’s me being influenced by Tarkovsky, not the reverse", and called Tarkovsky's film Andrei Rublev a "masterpiece".

The Greek-Australian filmmaker Alex Proyas was "extremely influenced" by Tarkovsky's work and cited Stalker as one of his favorite films.

The French philosopher Jean-Paul Sartre highly praised Tarkovsky's film Ivan's Childhood, saying that it was one of the most beautiful films he had ever seen.

The Japanese anime filmmaker Mamoru Oshii, known for his works such as Ghost in the Shell, was influenced by Tarkovsky.

The Indian-born British American novelist Salman Rushdie praised Tarkovsky and his work Solaris by calling it "a sci-fi masterpiece".

Film historian Steven Dillon says that much of subsequent film was deeply influenced by the films of Tarkovsky.

Mexican filmmaker Alejandro González Iñarritu is a huge fan of Tarkovsky. He once said in an interview: "Andrei Rublev is maybe my favorite film ever", and in another interview, he added: "I remember, the first time I saw a Tarkovsky film, I was shocked by it. I did not know what to do. I was shocked by it. I was fascinated, because suddenly I realized that film could have so many more layers to it than what I had imagined before". There are many direct references and hidden tributes to Tarkovsky's movies in Iñarritu's 2015 Oscar-winning drama The Revenant.

Danish film director Lars von Trier is a fervent admirer of Tarkovsky. He dedicated his 2009 film Antichrist to him, and, while discussing it with critic David Jenkins, asked: "Have you seen Mirror? I was hypnotised! I've seen it 20 times. It's the closest thing I've got to a religion – to me he is a god".

The Japanese composer Ryuichi Sakamoto was an admirer of Tarkovsky’s work, describing his penultimate solo album, async as “a soundtrack for an imaginary Tarkovsky film.” On Tarkovsky’s overall influence on his own work, Sakamoto stated, “As I’ve been making music and trying to go deeper and deeper, I was finally able to understand what the Tarkovsky movies are about — how symphonic they are — it’s almost music. Not just the sounds — it’s a symphony of moving images and sounds. They are more complex than music.”

Film festival
Two film festivals have been named in his honor:
 * International Human Rights Film Festival "Stalker", named after the film held annually in Moscow and regional centres since 1995
 * International Film Festival "Zerkalo" named after Andrei Tarkovsky (meaning "mirror"), "for fans of intellectual cinema"; also known as Tarkovsky Film festival – Zerkalo, Zerkalo International Film Festival, Andrei Tarkovsky Zerkalo International Film Festival, Tarkovskyfest or simply Zerkalo, The festival is organized by a committee headed by Mikhail Men, governor of Ivanovo Oblast. Sister of Andrei Tarkovsky, Marina Tarkovsky was one of the co-founders and organizers. From 2010 the festival was directed by Pavel Lungin. In 2020, the president of the festival was Russian director Sergei Bodrov. Owing to the COVID-19 pandemic in Russia, the 14th edition was held online in 2020, and appears to be the last one held, . The festival awards a number of prizes, including the Special Award for Contribution to Andrei Tarkovsky's Cinema. Held in Ivanovo since 2007, the festival is held in July each year, with the 16th edition scheduled for 22–27 July, to be held in various cities in the Ivanovo region, with special screenings in Moscow. Films from France, India, Greece, Serbia, Colombia, Kazakhstan and other countries were entered into the competition, and a gala night was dedicated to Tarkovsky's 90th birthday, on the main square of his hometown of Yuryevets on 22 July.

title: Andrei Tarkovsky