1.
Anatomical terminology
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Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors. Anatomical terminology uses many terms, suffixes, and prefixes deriving from Ancient Greek. These terms can be confusing to those unfamiliar with them, but can be more precise reducing ambiguity, also, since these anatomical terms are not used in everyday conversation, their meanings are less likely to change, and less likely to be misinterpreted. By using precise anatomical terminology such ambiguity is eliminated, an international standard for anatomical terminology, Terminologia Anatomica has been created. Anatomical terminology has quite regular morphology, the prefixes and suffixes are used to add meanings to different roots. The root of a term refers to an organ, tissue. For example, in the disorder hypertension, the prefix hyper- means high or over, the roots, prefixes and suffixes are often derived from Greek or Latin, and often quite dissimilar from their English-language variants. Latin names of such as musculus biceps brachii can be split up and refer to, musculus for muscle, biceps for two-headed. The first word tells us what we are speaking about, the second describes it, when describing the position of anatomical structures, structures may be described according to the anatomical landmark they are near. These landmarks may include structures, such as the umbilicus or sternum, or anatomical lines, the cephalon or cephalic region refers to the head. This area is differentiated into the cranium, facies, frons, oculus, auris, bucca, nausus, oris. The neck area is called the cervicis or cervical region, examples of structures named according to this include the frontalis muscle, submental lymph nodes, buccal membrane and orbicularis oculi muscle. Sometimes, unique terminology is used to reduce confusion in different parts of the body, for example, different terms are used when it comes to the skull in compliance with its embryonic origin and its tilted position compared to in other animals. Here, Rostral refers to proximity to the front of the nose, similarly, in the arms, different terminology is often used in the arms, in part to reduce ambiguity as what is the front, back, inner and outer surfaces. For this reason, the terms below are used, Radial referring to the radius bone, ulnar referring to the ulna bone, medially positioned when in the standard anatomical position. Other terms are used to describe the movement and actions of the hands and feet. International morphological terminology is used by the colleges of medicine and dentistry and it facilitates communication and exchanges between scientists from different countries of the world and it is used daily in the fields of research, teaching and medical care. The international morphological terminology refers to morphological sciences as a biological sciences branch, in this field, the form and structure are examined as well as the changes or developments in the organism
2.
Organ (anatomy)
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In biology, an organ or viscus is a collection of tissues joined in a structural unit to serve a common function. In anatomy, a viscus is an organ, and viscera is the plural form. Organs are composed of main tissue, parenchyma, and sporadic tissues, the main tissue is that which is unique for the specific organ, such as the myocardium, the main tissue of the heart, while sporadic tissues include the nerves, blood vessels, and connective tissues. The main tissues that make up an organ tend to have common embryologic origins, functionally related organs often cooperate to form whole organ systems. Organs exist in all biological organisms, in particular they are not restricted to animals. In single-cell organisms like bacteria, the analogue of an organ is called organelle. A hollow organ is an organ that forms a hollow tube or pouch, such as the stomach or intestine, or that includes a cavity. Two or more organs working together in the execution of a specific body function form an organ system, the functions of organ systems often share significant overlap. For instance, the nervous and endocrine system both operate via an organ, the hypothalamus. For this reason, the two systems are combined and studied as the neuroendocrine system, the same is true for the musculoskeletal system because of the relationship between the muscular and skeletal systems. Mammals such as humans have a variety of organ systems and these specific systems are also widely studied in human anatomy. Cardiovascular system, pumping and channeling blood to and from the body and lungs with heart, digestive system, digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, colon, rectum and anus. Excretory system, kidneys, ureters, bladder and urethra involved in balance, electrolyte balance. Integumentary system, skin, hair and nails, nervous system, collecting, transferring and processing information with brain, spinal cord and nerves. Reproductive system, the sex organs, such as ovaries, fallopian tubes, uterus, vulva, vagina, testes, vas deferens, seminal vesicles, prostate, respiratory system, the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs and diaphragm. Skeletal system, structural support and protection with bones, cartilage, ligaments, the organ level of organisation in animals can be first detected in flatworms and the more advanced phyla. The less-advanced taxa do not show consolidation of their tissues into organs, the study of plant organs is referred to as plant morphology, rather than anatomy, as in animal systems. Organs of plants can be divided into vegetative and reproductive, vegetative plant organs are roots, stems, and leaves
3.
Muscular system
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The muscular system is an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture, and circulates blood throughout the body, the muscular system in vertebrates is controlled through the nervous system, although some muscles can be completely autonomous. Together with the system it forms the musculoskeletal system, which is responsible for movement of the human body. There are three types of muscles, skeletal muscles, cardiac or heart muscles, and smooth muscles. Muscles provide strength, balance, posture, movement and heat for the body to keep warm, upon stimulation by an action potential, skeletal muscles perform a coordinated contraction by shortening each sarcomere. The best proposed model for understanding contraction is the sliding filament model of muscle contraction, within the sarcomere, actin and myosin fibers overlap in a contractile motion towards each other. Myosin filaments have club-shaped heads that project toward the actin filaments, larger structures along the myosin filament called myosin heads are used to provide attachment points on binding sites for the actin filaments. The myosin heads move in a style, they swivel toward the center of the sarcomere, detach. This is called a ratchet type drive system and this process consumes large amounts of adenosine triphosphate, the energy source of the cell. ATP binds to the bridges between myosin heads and actin filaments. The release of energy powers the swiveling of the myosin head, when ATP is used, it becomes adenosine diphosphate, and since muscles store little ATP, they must continuously replace the discharged ADP with ATP. Muscle tissue also contains a supply of a fast acting recharge chemical, creatine phosphate. Calcium ions are required for each cycle of the sarcomere, calcium is released from the sarcoplasmic reticulum into the sarcomere when a muscle is stimulated to contract. This calcium uncovers the actin binding sites, when the muscle no longer needs to contract, the calcium ions are pumped from the sarcomere and back into storage in the sarcoplasmic reticulum. There are approximately 639 skeletal muscles in the human body, at rest, the body produces the majority of its ATP aerobically in the mitochondria without producing lactic acid or other fatiguing byproducts. During exercise, the method of ATP production varies depending on the fitness of the individual as well as the duration, at lower activity levels, when exercise continues for a long duration, energy is produced aerobically by combining oxygen with carbohydrates and fats stored in the body. Aerobic training allows the delivery system to be more efficient. Recovery is very quick, with full creatine stores regenerated within five minutes, heart muscles are distinct from skeletal muscles because the muscle fibers are laterally connected to each other
4.
Human skeleton
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The human skeleton is the internal framework of the body. It is composed of around 300 bones at birth – this total decreases to 206 bones by adulthood after some bones have fused together, the bone mass in the skeleton reaches maximum density around age 20. The human skeleton can be divided into the skeleton and the appendicular skeleton. The axial skeleton is formed by the column, the rib cage. The appendicular skeleton, which is attached to the skeleton, is formed by the shoulder girdle, the pelvic girdle. The human skeleton performs six major functions, support, movement, protection, production of cells, storage of minerals. The human skeleton is not as sexually dimorphic as that of other primate species. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population, the human female pelvis is also different from that of males in order to facilitate child birth. Unlike most primates, human males do not have penile bones, the axial skeleton is formed by the vertebral column, a part of the rib cage, and the skull. The upright posture of humans is maintained by the skeleton, which transmits the weight from the head, the trunk. The bones of the spine are supported by many ligaments, the erector spinae muscles are also supporting and are useful for balance. The appendicular skeleton is formed by the pectoral girdles, the limbs, the pelvic girdle or pelvis. Their functions are to make locomotion possible and to protect the organs of digestion, excretion and reproduction. The skeleton serves six major functions, support, movement, protection, production of cells, storage of minerals. The skeleton provides the framework which supports the body and maintains its shape, the pelvis, associated ligaments and muscles provide a floor for the pelvic structures. Without the rib cages, costal cartilages, and intercostal muscles, the joints between bones allow movement, some allowing a wider range of movement than others, e. g. the ball and socket joint allows a greater range of movement than the pivot joint at the neck. Movement is powered by muscles, which are attached to the skeleton at various sites on bones. Muscles, bones, and joints provide the principal mechanics for movement and it is believed that the reduction of human bone density in prehistoric times reduced the agility and dexterity of human movement
5.
Cartilage
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It is not as hard and rigid as bone, but it is stiffer and less flexible than muscle. Because of its rigidity, cartilage often serves the purpose of holding tubes open in the body, cartilage is classified in three types, elastic cartilage, hyaline cartilage and fibrocartilage, which differ in relative amounts of collagen and proteoglycan. Cartilage does not contain blood vessels or nerves, nutrition is supplied to the chondrocytes by diffusion. The compression of the cartilage or flexion of the elastic cartilage generates fluid flow. Compared to other tissues, cartilage has a very slow turnover of its extracellular matrix. In embryogenesis, the system is derived from the mesoderm germ layer. Following the initial chondrification that occurs during embryogenesis, cartilage growth consists mostly of the maturing of immature cartilage to a mature state. The division of cells within cartilage occurs very slowly, and thus growth in cartilage is not based on an increase in size or mass of the cartilage itself. The articular cartilage function is dependent on the composition of the extracellular matrix. The ECM consists mainly of proteoglycan and collagens, the main proteoglycan in cartilage is aggrecan, which, as its name suggests, forms large aggregates with hyaluronan. These aggregates are negatively charged and hold water in the tissue, the collagen, mostly collagen type II, constrains the proteoglycans. The ECM responds to tensile and compressive forces that are experienced by the cartilage, cartilage growth thus refers to the matrix deposition, but can also refer to both the growth and remodeling of the extracellular matrix. Due to the stress on the patellofemoral joint during resisted knee flexion. The mechanical properties of articular cartilage in load bearing joints such as knee and hip have been studied extensively at macro, micro and these mechanical properties include the response of cartilage in frictional, compressive, shear and tensile loading. Cartilage is resilient and displays viscoelastic properties, lubricin, a glycoprotein abundant in cartilage and synovial fluid, plays a major role in bio-lubrication and wear protection of cartilage. Cartilage has limited capabilities, Because chondrocytes are bound in lacunae. Therefore, cartilage damage is difficult to heal, also, because hyaline cartilage does not have a blood supply, the deposition of new matrix is slow. Damaged hyaline cartilage is replaced by fibrocartilage scar tissue
6.
Tendon
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A tendon or sinew is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments, both are made of collagen, ligaments join one bone to another bone, while tendons connect muscle to bone. Histologically, tendons consist of dense connective tissue fascicles encased in dense irregular connective tissue sheaths. Normal healthy tendons are composed mostly of parallel arrays of collagen fibers closely packed together, the collagen portion is made up of 97–98% type I collagen, with small amounts of other types of collagen. After secretion from the cell, the peptides are cleaved by procollagen N- and C-proteinases. A collagen molecule is about 300 nm long and 1–2 nm wide, and the diameter of the fibrils that are formed can range from 50–500 nm. In tendons, the fibrils then assemble further to form fascicles, which are about 10 mm in length with a diameter of 50–300 μm, fascicles are bound by the endotendineum, which is a delicate loose connective tissue containing thin collagen fibrils. and elastic fibres. Groups of fascicles are bounded by the epitenon, filling the interstitia within the fascia where the tendon is located is the paratenon a fatty areolar tissue. The major GAG components of the tendon are dermatan sulfate and chondroitin sulfate, the dermatan sulfate side chains of decorin aggregate in solution, and this behavior can assist with the assembly of the collagen fibrils. The tenocytes produce the collagen molecules, which aggregate end-to-end and side-to-side to produce collagen fibrils, fibril bundles are organized to form fibres with the elongated tenocytes closely packed between them. There is a network of cell processes associated with collagen in the tendon. The cells communicate with other through gap junctions, and this signalling gives them the ability to detect. Blood vessels may be visualized within the endotendon running parallel to collagen fibres, the internal tendon bulk is thought to contain no nerve fibres, but the epitenon and paratenon contain nerve endings, while Golgi tendon organs are present at the junction between tendon and muscle. Tendon length varies in all groups and from person to person. Tendon length is, in practice, the deciding factor regarding actual and potential muscle size, successful bodybuilders will generally have shorter tendons. Conversely, in sports requiring athletes to excel in such as running or jumping, it is beneficial to have longer than average Achilles tendon. Traditionally, tendons have been considered to be a mechanism by which muscles connect to bone and this connection allows tendons to passively modulate forces during locomotion, providing additional stability with no active work. However, over the past two decades, much research focused on the properties of some tendons and their ability to function as springs
7.
Ligament
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In anatomy, a ligament is the fibrous connective tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament. Ligament can also refer to, Peritoneal ligament, a fold of peritoneum or other membranes, fetal remnant ligament, the remnants of a fetal tubular structure. Periodontal ligament, a group of fibers that attach the cementum of teeth to the alveolar bone. The study of ligaments is known as desmology, ligaments are similar to tendons and fasciae as they are all made of connective tissue. The differences in them are in the connections that they make, ligaments connect one bone to bone, tendons connect muscle to bone. These are all found in the system of the human body. Ligament most commonly refers to a band of dense connective tissue bundles made of collagenous fibers. Ligaments connect bones to other bones to form joints, while tendons connect bone to muscle, some ligaments limit the mobility of articulations, or prevent certain movements altogether. Capsular ligaments are part of the capsule that surrounds synovial joints. Extra-capsular ligaments join together in harmony with the other ligaments and provide joint stability, intra-capsular ligaments, which are much less common, also provide stability but permit a far larger range of motion. Cruciate ligaments are paired ligaments in the form of a cross and they gradually strain when under tension, and return to their original shape when the tension is removed. However, they retain their original shape when extended past a certain point or for a prolonged period of time. This is one reason why dislocated joints must be set as quickly as possible, if the ligaments lengthen too much, then the joint will be weakened, athletes, gymnasts, dancers, and martial artists perform stretching exercises to lengthen their ligaments, making their joints more supple. The term hypermobility refers to people with more-elastic ligaments, allowing their joints to stretch and contort further, the consequence of a broken ligament can be instability of the joint. Not all broken ligaments need surgery, but, if surgery is needed to stabilise the joint, if it is not possible to fix the broken ligament, other procedures such as the Brunelli procedure can correct the instability. Instability of a joint can over time lead to wear of the cartilage, one of the most often torn ligaments in the body is the anterior cruciate ligament. The ACL is one of the ligaments crucial to stability and persons who tear their ACL often seek to undergo reconstructive surgery. One of these techniques is the replacement of the ligament with an artificial material, an artificial ligament is a reinforcing material that is used to replace a torn ligament, such as the ACL
8.
Joint
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A joint or articulation is the connection made between bones in the body which link the skeletal system into a functional whole. They are constructed to allow for different degrees and types of movement, other joints such as sutures between the bones of the skull permit very little movement in order to protect the brain and the sense organs. The connection between a tooth and the jawbone is also called a joint, and is described as a fibrous joint known as a gomphosis, joints are classified both structurally and functionally. Joints are mainly classified structurally and functionally, structural classification is determined by how the bones connect to each other, while functional classification is determined by the degree of movement between the articulating bones. In practice, there is significant overlap between the two types of classifications, a facet joint is the joint between two articular processes between two vertebrae. Structural classification names and divides joints according to the type of binding tissue that connects the bones to each other, joints can also be classified functionally according to the type and degree of movement they allow, Joint movements are described with reference to the basic anatomical planes. Synarthrosis – permits little or no mobility, most synarthrosis joints are fibrous joints. Most amphiarthrosis joints are cartilaginous joints, Synovial joints can in turn be classified into six groups according to the type of movement they allow, plane joint, ball and socket joint, hinge joint, pivot joint, condyloid joint and saddle joint. Joints can also be classified, according to the number of axes of movement they allow, another classification is according to the degrees of freedom allowed, and distinguished between joints with one, two or three degrees of freedom. A further classification is according to the number and shapes of the surfaces, flat, concave. Types of articular surfaces include trochlear surfaces, joints can also be classified based on their anatomy or on their biomechanical properties. Swimming is a way to exercise the joints with minimal damage. A joint disorder is termed arthropathy, and when involving inflammation of one or more joints the disorder is called arthritis, most joint disorders involve arthritis, but joint damage by external physical trauma is typically not termed arthritis. Arthropathies are called polyarticular when involving many joints and monoarticular when involving only a single joint, arthritis is the leading cause of disability in people over the age of 55. There are many different forms of arthritis, each of which has a different cause, furthermore, there is emerging evidence that abnormal anatomy may contribute to early development of osteoarthritis. Other forms of arthritis are rheumatoid arthritis and psoriatic arthritis, which are diseases in which the body is attacking itself. Septic arthritis is caused by joint infection, gouty arthritis is caused by deposition of uric acid crystals in the joint that results in subsequent inflammation. Additionally, there is a common form of gout that is caused by the formation of rhomboidal-shaped crystals of calcium pyrophosphate
9.
Connective tissue
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Connective tissue is one of the four types of biological tissue that supports, connects or separates different types of tissues and organs in the body. The other three types are epithelial, muscle, and nervous tissue, Connective tissue is found in between other tissues everywhere in the body, including the nervous system. In the central system, the three outer membranes that envelop the brain and spinal cord are composed of connective tissue. All connective tissue consists of three components, fibers, ground substance and cells. Blood and lymph lack the fiber component, all are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells, Connective tissue can be broadly subdivided into connective tissue proper, and special connective tissue. Connective tissue proper consists of connective tissue and dense connective tissue Special connective tissue consists of reticular connective tissue, adipose tissue, cartilage, bone. Other kinds of connective tissues include fibrous, elastic, and lymphoid connective tissues, new vascularised connective tissue that forms in the process of wound healing is termed granulation tissue. Fibroblasts are the responsible for the production of some CT. Type I collagen, is present in forms of connective tissue. Characteristics of CT, Cells are spread through an extracellular fluid, ground substance - A clear, colorless, and viscous fluid containing glycosaminoglycans and proteoglycans to fix the body water and the collagen fibers in the intercellular spaces. Ground substance slows the spread of pathogens, not all types of CT are fibrous. Examples of non-fibrous CT include adipose tissue and blood, adipose tissue gives mechanical cushioning to the body, among other functions. Although there is no dense collagen network in adipose tissue, groups of cells are kept together by collagen fibers. The matrix of blood is plasma, both the ground substance and proteins create the matrix for CT. Types of fibers, Connective tissue has a variety of functions that depend on the types of cells. They also allow organs to resist stretching and tearing forces, elastic fibers, made from elastin and fibrillin, also provide resistance to stretch forces. They are found in the walls of blood vessels and in certain ligaments
10.
Calcium
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Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft grayish-yellow alkaline earth metal, fifth-most-abundant element by mass in the Earths crust, the ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate. Free calcium metal is too reactive to occur in nature, Calcium is produced in supernova nucleosynthesis. Calcium is a trace element in living organisms. It is the most abundant metal by mass in animals, and it is an important constituent of bone, teeth. In cell biology, the movement of the calcium ion into, Calcium carbonate and calcium citrate are often taken as dietary supplements. Calcium is on the World Health Organizations List of Essential Medicines, Calcium has a wide variety of applications, almost all of which are associated with calcium compounds and salts. Calcium metal is used as a deoxidizer, desulfurizer, and decarbonizer for production of ferrous and nonferrous alloys. In steelmaking and production of iron, Ca reacts with oxygen, Calcium carbonate is used in manufacturing cement and mortar, lime, limestone and aids in production in the glass industry. It also has chemical and optical uses as mineral specimens in toothpastes, Calcium hydroxide solution is used to detect the presence of carbon dioxide in a gas sample bubbled through a solution. The solution turns cloudy where CO2 is present, Calcium arsenate is used in insecticides. Calcium carbide is used to make acetylene gas and various plastics, Calcium chloride is used in ice removal and dust control on dirt roads, as a conditioner for concrete, as an additive in canned tomatoes, and to provide body for automobile tires. Calcium citrate is used as a food preservative, Calcium cyclamate is used as a sweetening agent in several countries. In the United States, it has been outlawed as a suspected carcinogen, Calcium gluconate is used as a food additive and in vitamin pills. Calcium hypochlorite is used as a swimming pool disinfectant, as an agent, as an ingredient in deodorant. Calcium permanganate is used in rocket propellant, textile production, as a water sterilizing agent. Calcium phosphate is used as a supplement for animal feed, fertilizer, in production for dough and yeast products, in the manufacture of glass. Calcium phosphide is used in fireworks, rodenticide, torpedoes, Calcium sulfate is used as common blackboard chalk, as well as, in its hemihydrate form, Plaster of Paris
11.
Phosphorus
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Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but because it is reactive, phosphorus is never found as a free element on Earth. At 0. 099%, phosphorus is the most abundant pnictogen in the Earths crust, with few exceptions, minerals containing phosphorus are in the maximally oxidised state as inorganic phosphate rocks. The glow of phosphorus itself originates from oxidation of the white phosphorus — a process now termed chemiluminescence, together with nitrogen, arsenic, antimony, and bismuth, phosphorus is classified as a pnictogen. Phosphates are a component of DNA, RNA, ATP, and the phospholipids, demonstrating the link between phosphorus and life, elemental phosphorus was first isolated from human urine, and bone ash was an important early phosphate source. Phosphate mines contain fossils, especially marine fossils, because phosphate is present in the deposits of animal remains. Low phosphate levels are an important limit to growth in aquatic systems. The vast majority of compounds produced are consumed as fertilisers. Phosphate is needed to replace the phosphorus that plants remove from the soil, other applications include the role of organophosphorus compounds in detergents, pesticides, and nerve agents. Phosphorus exists as several forms that exhibit different properties. The two most common allotropes are white phosphorus and red phosphorus, from the perspective of applications and chemical literature, the most important form of elemental phosphorus is white phosphorus, often abbreviated as WP. It is a soft and waxy solid consists of tetrahedral P4 molecules. This P4 tetrahedron is also present in liquid and gaseous phosphorus up to the temperature of 800 °C when it starts decomposing to P2 molecules, White phosphorus exists in two crystalline forms, α and β. At room temperature, the α-form is stable, which is common and it has cubic crystal structure and at 195.2 K, it transforms into β-form. These forms differ in terms of the orientations of the constituent P4 tetrahedra. White phosphorus is the least stable, the most reactive, the most volatile, the least dense, White phosphorus gradually changes to red phosphorus. This transformation is accelerated by light and heat, and samples of white phosphorus almost always some red phosphorus. For this reason, white phosphorus that is aged or otherwise impure is also called yellow phosphorus, when exposed to oxygen, white phosphorus glows in the dark with a very faint tinge of green and blue
12.
Haematopoiesis
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Haematopoiesis is the formation of blood cellular components. All cellular blood components are derived from stem cells. In a healthy person, approximately 1011–1012 new blood cells are produced daily in order to maintain steady state levels in the peripheral circulation. Haematopoietic stem cells reside in the medulla of the bone and have the ability to give rise to all of the different mature blood cell types and tissues. HSCs are self-renewing cells, when they proliferate, at least some of their daughter cells remain as HSCs, so the pool of stem cells is not depleted. This phenomenon is called asymmetric division. The other daughters of HSCs can follow any of the other pathways that lead to the production of one or more specific types of blood cell. The pool of progenitors is heterogeneous and can be divided into two groups, long-term self-renewing HSC and only transiently self-renewing HSC, also called short-terms and this is one of the main vital processes in the body. All blood cells are divided into three lineages, erythroid cells are the oxygen carrying red blood cells. Both reticulocytes and erythrocytes are functional and are released into the blood, in fact, a reticulocyte count estimates the rate of erythropoiesis. Lymphocytes are the cornerstone of the immune system. They are derived from common lymphoid progenitors, the lymphoid lineage is primarily composed of T-cells and B-cells. In developing embryos, blood formation occurs in aggregates of cells in the yolk sac. As development progresses, blood formation occurs in the spleen, liver, when bone marrow develops, it eventually assumes the task of forming most of the blood cells for the entire organism. However, maturation, activation, and some proliferation of lymphoid cells occurs in the spleen, thymus, in children, haematopoiesis occurs in the marrow of the long bones such as the femur and tibia. In adults, it mainly in the pelvis, cranium, vertebrae. In some cases, the liver, thymus, and spleen may resume their haematopoietic function and it may cause these organs to increase in size substantially. During fetal development, since bones and thus the bone marrow develop later, therefore, the liver is enlarged during development. In some vertebrates, haematopoiesis can occur wherever there is a loose stroma of connective tissue and slow blood supply, such as the gut, spleen or kidney
13.
Medical diagnosis
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Medical diagnosis is the process of determining which disease or condition explains a persons symptoms and signs. It is most often referred to as diagnosis with the context being implicit. The information required for diagnosis is typically collected from a history, often, one or more diagnostic procedures, such as diagnostic tests, are also done during the process. Sometimes Posthumous diagnosis is considered a kind of medical diagnosis, Diagnosis is often challenging, because many signs and symptoms are nonspecific. For example, redness of the skin, by itself, is a sign of many disorders, thus differential diagnosis, in which several possible explanations are compared and contrasted, must be performed. This involves the correlation of various pieces of information followed by the recognition and differentiation of patterns, occasionally the process is made easy by a sign or symptom that is pathognomonic. Diagnosis is a component of the procedure of a doctors visit. From the point of view of statistics, the procedure involves classification tests. The first recorded examples of medical diagnosis are found in the writings of Imhotep in ancient Egypt, a Babylonian medical textbook, the Diagnostic Handbook written by Esagil-kin-apli, introduced the use of empiricism, logic and rationality in the diagnosis of an illness or disease. Traditional Chinese Medicine, as described in the Yellow Emperors Inner Canon or Huangdi Neijing, specified four diagnostic methods, inspection, auscultation-olfaction, interrogation, hippocrates was known to make diagnoses by tasting his patients urine and smelling their sweat. This article uses diagnostician as any of these person categories, a diagnostic procedure does not necessarily involve elucidation of the etiology of the diseases or conditions of interest, that is, what caused the disease or condition. Such elucidation can be useful to optimize treatment, further specify the prognosis or prevent recurrence of the disease or condition in the future, the initial task is to detect a medical indication to perform a diagnostic procedure. Indications include, Detection of any deviation from what is known to be normal, such as can be described in terms of, for example, anatomy, physiology, pathology, psychology, a complaint expressed by a patient. The fact that a patient has sought a diagnostician can itself be an indication to perform a diagnostic procedure, even during an already ongoing diagnostic procedure, there can be an indication to perform another, separate, diagnostic procedure for another, potentially concomitant, disease or condition. A diagnostic test is any kind of medical test performed to aid in the diagnosis or detection of disease, Diagnostic tests can also be used to provide prognostic information on people with established disease. Processing of the answers, findings or other results, consultations with other providers and specialists in the field may be sought. There are a number of methods or techniques that can be used in a diagnostic procedure, in reality, a diagnostic procedure may involve components of multiple methods. The final result may also remain a list of possible conditions, the resultant diagnostic opinion by this method can be regarded more or less as a diagnosis of exclusion
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Human
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Modern humans are the only extant members of Hominina tribe, a branch of the tribe Hominini belonging to the family of great apes. Several of these hominins used fire, occupied much of Eurasia and they began to exhibit evidence of behavioral modernity around 50,000 years ago. In several waves of migration, anatomically modern humans ventured out of Africa, the spread of humans and their large and increasing population has had a profound impact on large areas of the environment and millions of native species worldwide. Humans are uniquely adept at utilizing systems of communication for self-expression and the exchange of ideas. Humans create complex structures composed of many cooperating and competing groups, from families. Social interactions between humans have established a wide variety of values, social norms, and rituals. These human societies subsequently expanded in size, establishing various forms of government, religion, today the global human population is estimated by the United Nations to be near 7.5 billion. In common usage, the word generally refers to the only extant species of the genus Homo—anatomically and behaviorally modern Homo sapiens. In scientific terms, the meanings of hominid and hominin have changed during the recent decades with advances in the discovery, there is also a distinction between anatomically modern humans and Archaic Homo sapiens, the earliest fossil members of the species. The English adjective human is a Middle English loanword from Old French humain, ultimately from Latin hūmānus, the words use as a noun dates to the 16th century. The native English term man can refer to the species generally, the species binomial Homo sapiens was coined by Carl Linnaeus in his 18th century work Systema Naturae. The generic name Homo is a learned 18th century derivation from Latin homō man, the species-name sapiens means wise or sapient. Note that the Latin word homo refers to humans of either gender, the genus Homo evolved and diverged from other hominins in Africa, after the human clade split from the chimpanzee lineage of the hominids branch of the primates. The closest living relatives of humans are chimpanzees and gorillas, with the sequencing of both the human and chimpanzee genome, current estimates of similarity between human and chimpanzee DNA sequences range between 95% and 99%. The gibbons and orangutans were the first groups to split from the leading to the humans. The splitting date between human and chimpanzee lineages is placed around 4–8 million years ago during the late Miocene epoch, during this split, chromosome 2 was formed from two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. There is little evidence for the divergence of the gorilla, chimpanzee. Each of these species has been argued to be an ancestor of later hominins
15.
Blood
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Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. In vertebrates, it is composed of blood cells suspended in blood plasma, plasma, which constitutes 55% of blood fluid, is mostly water, and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide, and blood cells themselves. Albumin is the protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are red blood cells, white blood cells. The most abundant cells in blood are red blood cells. These contain hemoglobin, a protein, which facilitates oxygen transport by reversibly binding to this respiratory gas. In contrast, carbon dioxide is mostly transported extracellularly as bicarbonate ion transported in plasma, vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, insects and some mollusks use a fluid called hemolymph instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this blood does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their system to suffice for supplying oxygen. Jawed vertebrates have an immune system, based largely on white blood cells. White blood cells help to resist infections and parasites, platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system, Blood is circulated around the body through blood vessels by the pumping action of the heart. Medical terms related to blood often begin with hemo- or hemato- from the Greek word αἷμα for blood. In terms of anatomy and histology, blood is considered a form of connective tissue, given its origin in the bones. The average adult has a volume of roughly 5 litres. These blood cells consist of erythrocytes, leukocytes, and thrombocytes, by volume, the red blood cells constitute about 45% of whole blood, the plasma about 54. 3%, and white cells about 0. 7%. Whole blood exhibits non-Newtonian fluid dynamics, if all human hemoglobin were free in the plasma rather than being contained in RBCs, the circulatory fluid would be too viscous for the cardiovascular system to function effectively. One microliter of blood contains,4.7 to 6.1 million,4.2 to 5.4 million erythrocytes, Red blood cells contain the bloods hemoglobin, mature red blood cells lack a nucleus and organelles in mammals
. PMID 18259783.
