What are the eight functions of the human body?

Respiratory system: It consists of nose, pharynx, larynx, trachea, bronchi and lungs. Digestive system: including oral cavity, pharynx, esophagus, stomach, intestine and other digestive tracts and various digestive glands. Endocrine system: including pituitary gland, thyroid gland, parathyroid gland, adrenal gland, islet, gonad, thymus, etc. Immune system: including innate immunity, such as tears, mucous membranes and lymph, and acquired immunity, such as antibodies produced by immunity. Blood circulation system: It is composed of the heart, various blood vessels and blood, and the lymphatic system is an integral part of the blood circulation system. Nervous system: including brain, diencephalon, brain stem, cerebellum, spinal cord, cranial nerve, spinal nerve, autonomic nerve, etc. Urogenital system: urinary system consisting of kidney, ureter, bladder and urethra; Male and female reproductive systems are composed of different reproductive organs. Motor system: It is mainly composed of bones, joints and skeletal muscles. One of the eight systems of human body (1) respiratory system The respiratory system includes respiratory tract and lung. The respiratory tract is the ventilation duct and the lung is the gas exchange organ. The main function of the respiratory system is to continuously inhale fresh air from the outside and exhale carbon dioxide from the body to ensure the smooth metabolism of the human body. Respiratory tract includes nose, pharynx, larynx, trachea and main bronchus, which is called upper respiratory tract clinically; Trachea, main bronchus and its branches are called lower respiratory tract. 1, lung structure The lung surface is covered with the dirty pleura, which is located in the chest cavity, one left and one right, separated on both sides of the mediastinum. Because there is a liver under the right diaphragm and the heart is located to the left, the right lung is short and wide and the left lung is long and narrow. The two lungs are approximately semicircular cones with a tip, a bottom, two sides and three edges. 2, the function of the lungs The function of the lungs includes respiratory function and non-respiratory function. Respiratory function refers to the function of gas exchange, that is, exchanging oxygen into blood and carbon dioxide out of blood. The non-respiratory function of lung refers to the defensive function, filtering function and metabolic function of lung. (1) The defensive function of the lung ① regulates inspiration. Upper respiratory tract mucosa has a large surface area and abundant blood supply, which can warm and humidify the inhaled air and protect the lungs. The trachea and bronchus have little blood supply and no air conditioning function. Therefore, during tracheal intubation or tracheotomy, attention should be paid to artificially heating and humidifying the inhaled air. (2) Blocking and clearing action: nasal hair and nasal mucosa can block the entry of foreign bodies in the inhaler; Smaller foreign bodies entering the lower respiratory tract can also be removed by coughing, sneezing reflex, mucus and cilia. ③ Phagocytosis: Pulmonary alveolar macrophages are rich in lysosomes, which can surround phagocytic particles, kill bacteria and act as "scavengers". Smoking and inhaling harmful gases can damage the vitality of macrophages. (2) The filtering function of the lung. Small blood vessels in pulmonary circulation can prevent tiny particles (such as blood clots, fat cells, concentrated red blood cells, platelets, white blood cell clumps, stored blood fragments, bubbles, exfoliated cancer cells, particles in intravenous injection, etc. ) enter the systemic circulation for various reasons, thus preventing coronary artery embolism or cerebral circulation embolism. (3) Metabolic function of lung The lung participates in the metabolism of many bioactive substances. In recent years, it is particularly striking that pulmonary vascular endothelial cells play an important role in the synthesis, release, activation and inactivation of various vasoactive substances in lung blood. (4) Other functions In addition, the lung also acts as a blood bank; Participate in the regulation of coagulation system and fibrinolysis system; A neuroendocrine cell similar to APUD cells is scattered in the lung, which participates in paracrine and regulates local functional activities. Eight systems of human body (II) Digestive system 1, composition of digestive system The digestive system consists of two parts: digestive tube and digestive gland. The digestive tract includes mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus. Usually, the digestive tube from the mouth to the duodenum is called the upper digestive tube, and the lower digestive tube below the jejunum is called the lower digestive tube. Digestive glands are organs that secrete digestive juice, including salivary glands, liver and pancreas, as well as small digestive glands distributed in the wall of digestive tubes, such as stomach glands and intestinal glands. The length of human intestine is about 4 ~ 5 times of height. Most ethnic groups in East Asia are engaged in farming, mainly feeding on rice, shells and omnivores. Even in recent years, the dietary life of orientals is comparable to that of westerners, but the degree of meat consumption is still far less than that of Europeans and Americans. Will the difference in diet content for such a long time also affect the shape of the large intestine? In addition, we see that the intestines of herbivores are longer than those of carnivores. For example, the length of a cow's intestine (about 57m) is 22 times its body length! The intestine of a pig is 16 times its body length (about 24m), and that of a horse is 10 times its body length (about 30m). The intestinal length of carnivorous cats is about 4-5 times (about 2m) of their body length, while dogs are omnivorous, and the intestinal length is about 5 times (about 5m) of their body length. The human small intestine is about 5m, and the large intestine is about 1.5m, which is about 4-5 times the height. However, according to the actual situation, the length of the large intestine of orientals may be longer. In the whole digestive system, the small intestine is responsible for digestion and absorption. In the small intestine, digestive juice breaks down food into the smallest units, which are then absorbed by blood vessels and lymph glands. The second is to come down, and the job of the large intestine is to clean up the aftermath. The food residue flowing from the small intestine is like a muddy liquid, 90% ~ 95% of which is water. When these muddy liquids pass through the large intestine, the water will be gradually absorbed, turned into feces, and then excreted. 2, the function of the digestive system The basic function of the digestive system is to ingest food, make food undergo physical (mechanical) digestion and chemical digestion in the digestive tube, absorb nutrients in it, and excrete the remaining residues to ensure the normal metabolism of the human body. The process of food breaking down into small molecules in the digestive tract is called digestion. The process of digested small molecular nutrients, water and inorganic salts entering the blood and lymph through the digestive tract mucosa is called absorption. There are two ways to digest. Physical digestion: it is the initial digestion of food with physical changes in the digestive tract, which is mainly realized by the relaxation and contraction of smooth muscle of the digestive tract. Its function is to grind food, make it fully mixed with digestive juice, and gradually push food from the upper section of digestive tube to the lower section. Chemical digestion is the complete digestion of food in the digestive tube, which is completed by digestive enzymes secreted by digestive glands. Digestive enzymes can decompose protein, fat, sugar and other macromolecules that cannot be absorbed directly into small molecules that can be absorbed. The two ways of food digestion in the digestive tube are carried out simultaneously. The endocrine system and nervous system are closely related in function and cooperate with each other. * * * Regulate various functional activities of the body and keep the internal environment relatively stable. The endocrine system consists of endocrine glands and endocrine cells scattered throughout the body. The main endocrine glands in human body are pituitary gland, thyroid gland, parathyroid gland, adrenal gland, gonad and pineal gland. The endocrine cells scattered all over the body are mainly distributed in digestive tract mucosa, islets, hypothalamus, kidneys, cardiovascular system, lungs and so on. The main function of human endocrine system is to regulate metabolism and reproduction, promote development and growth, and maintain the homeostasis of internal environment. The endocrine system is not an independent regulatory system of the nervous system. Many endocrine glands are directly or indirectly regulated by the nervous system and play a regulatory role under the leadership of the nervous system. The immune system (4) of the eight human systems is 1. The immune system is the body's defense structure to protect itself. It is mainly composed of lymphoid organs (thymus, lymph nodes, spleen and tonsils), lymphoid tissues of other organs, lymphocytes and antigen presenting cells all over the body. Lymphocyte is the core component of the immune system, which enables the immune system to recognize and remember. The function of the immune system mainly has two aspects: ① identifying and eliminating microorganisms, foreign cells or macromolecular substances (antigens) that invade the human body; ② Monitor the internal stability of the body and remove cells (tumor cells, virus-infected cells, etc.) whose surface antigens have changed. ) .2. Thymus function Thymus is an important organ for cultivating and screening T cells. Thymosin and thymosin secreted by thymocytes play an important role in the proliferation and development of T cells. All kinds of virgin T cells cultured in thymus are transported to peripheral lymphoid organs and lymphoid tissues through blood flow, and further differentiated and matured. 3, the role of lymph nodes (1) filter lymph pathogens invade human subcutaneous mucosa, easily enter the human lymphatic circulation through the endothelial space of lymphatic capillaries, and return to human lymph nodes. When lymph flows slowly through the lymphatic sinus, macrophages can remove foreign bodies from it. (2) After antigens such as bacteria involved in immune response enter lymph nodes, macrophages and interdigital cells can capture and process antigens, and then transmit antigen information to T. B lymphocytes, causing immune response. After being stimulated by antigen, T cells and B cells in lymph nodes become mother cells, then divide and proliferate in large numbers, and finally differentiate into effective T lymphocytes and plasma cells, which participate in cellular immune response and humoral immune response respectively. 4, the function of the spleen (1) The main parts of blood filtration in the spleen are the splenic cord and the marginal area, which contain a large number of macrophages, which can devour and remove foreign bodies, germs and aging and dead blood cells in the blood. When the spleen is hyperactive, it will cause the decrease of red blood cells or platelets due to excessive blood killing. (2) The human spleen can store about 40m 1 of blood, mainly in the blood sinus. When the body needs blood, the smooth muscle contraction in the spleen can transport blood to the blood circulation to meet the urgent needs of the body (such as massive blood loss and strenuous exercise). (3) Hematopoiety: In the early embryo, the spleen, like other organs, can produce various blood cells. Since the bone marrow began to make blood, the spleen has become a lymphoid organ, which can only produce lymphocytes and plasma cells, but it still has the function of making various blood cells; When the body is seriously ischemic or in some pathological conditions, the spleen can restore hematopoietic function. (4) Immunity: T cells account for 40%, B cells account for 55%, and some K cells and NK cells participate in the immune response of the body. Spleen is the organ that produces the most antibodies in the body. The blood circulation system (5) of the eight systems of the human body is a continuous pipeline system for the human body to perform transportation functions, including the heart, blood vessels and lymphatic system. The heart is the power organ to promote blood flow; Blood vessel is a conduit for blood flow, which consists of arteries, capillaries and veins. Lymphatic vessels originate from the gap at the blind end, and lymph flows along the lymphatic vessels to the heart, passes through the lymph nodes, and flows into human veins. Lymphatic vessels are usually considered as auxiliary ducts of veins. The main function of blood circulation system is material transportation. Through this system, oxygen and various nutrients are transported to organs, tissues and cells of the whole body, and at the same time, the metabolites of various tissues are transported to the excretory organs. In addition, it also delivers hormones to target cells to achieve humoral regulation; Transportation of white blood cells and various immune substances to complete immune function, transportation of heat to keep body temperature constant, and maintenance of internal environment homeostasis also require the participation of circulatory system. Recent studies have shown that the cardiovascular system also has endocrine function. For example, myocardial fibers can secrete atrial natriuretic peptide, which makes people have a further understanding of the function of blood circulation system. Under normal circumstances, people will lose consciousness when the blood circulation stops for 3 ~ 10 seconds. After stopping for 5 ~ 7 minutes, the cerebral cortex will be irreversibly damaged, so blood circulation is one of the important functions of the human body. 1. Blood Blood is a special connective tissue, which consists of blood cells and plasma. Blood fills the cardiovascular system, circulates under the drive of the heart, and communicates with the internal and external environment of the human body. Insufficient blood supply to any tissues and organs of the body will cause serious injuries. After anticoagulation of blood components (1), fresh blood is placed in a hydrometer tube and centrifuged at a speed of 3000 r/min for 30 minutes, which can be displayed as three layers in a test tube. The upper yellowish liquid is plasma; The lower layer is dark red, which is red blood cells; The thin gray layer in the middle is white blood cells and platelets. The volume percentage of blood cells in whole blood measured by this method is called hematocrit. Normal adult male is 40% ~ 50%, and female is 37% ~ 48%, which can reflect the relative value of blood cell number in blood. The composition of blood can be summarized as follows: plasma is equivalent to the gap of loose connective tissue, and it is an aqueous solution containing many solutes, of which water accounts for about 9 1% ~ 92%. Solute contains a variety of electrolytes, small molecular organic compounds (nutrients, metabolites, hormones, etc. ) and some gases form a crystal substance solution. These solutes and water can easily exchange with interstitial fluid through capillaries, and the changes of their physical and chemical properties are often parallel to interstitial fluid. Another important solute in plasma is plasma protein, which is the main difference between plasma and tissue fluid. Plasma protein is the general name of many protein, including many protein with different molecular sizes, structures and functions, among which albumin is the most, globulin is the second, and fibrinogen is the least. Globulins can be divided into α 1, α2, β and γ globulin by electrophoresis. If fresh blood in vitro is put in a test tube without anticoagulation, the blood will coagulate itself and form a colloidal blood clot. When the blood clot retracts, a yellowish liquid called serum is precipitated, which is equivalent to the matrix of loose connective tissue. The main difference between plasma and serum is the lack of fibrinogen and a small amount of other plasma proteins involved in coagulation, but a small amount of substances released by platelets during coagulation are added. (2) Function of blood ① Transport function Red blood cells have the function of transporting O 2 and CO 2. Plasma can transport various nutrients, metabolites and various regulatory substances, antigens, antibodies and so on. With blood circulation, O 2 and nutrients are transported to tissues and cells, while metabolites such as CO 2 and urea are transported to lungs, kidneys and other organs for excretion. The hormone is delivered to the target organ, which plays a role in regulating body fluids and ensuring normal metabolism. (2) Buffering effect Blood contains a variety of buffering substances, which can buffer the possible acid-base changes in plasma and keep the blood value relatively constant. (3) Immune and defensive functions: White blood cells, immunoglobulins and complements in the blood phagocytize, decompose and finally remove foreign bodies such as bacteria invaded by the human body and aging and necrotic tissues and cells in the body through specific and nonspecific immune reactions, thus playing a defensive role in the body. Coagulation factors in platelets and plasma participate in the process of hemostasis and coagulation, and also have a protective effect on the body. (4) regulating body temperature. Water in the blood can absorb a lot of heat generated in the body, and through blood circulation, bring the heat in the deep layer of the body to the body surface for dissipation, and keep the body temperature relatively constant. (III) Morphology, structure and function of blood cells ① Functions and characteristics of red blood cells A. Number and function of red blood cells: normal adult male: (4.0 ~ 5.5) ×1012/L (4 million ~ 5.5 million /μ 1), female: (3. The normal value of hemoglobin in adult males is 120 ~ 160 g/L, and that in females is110 ~1509 g/L. The main function of red blood cells is to transport O 2 and CO 2. There are many buffering pairs in red blood cells, which have a certain buffering effect on acid and alkali substances produced by the body. When hemoglobin combines with carbon monoxide to form carbon monoxide hemoglobin (Hb-CO) or Fe 2+ in the molecule is oxidized to Fe 3+, it will lose its function. B characteristics of red blood cells: suspension stability, plastic deformation and osmotic brittleness of red blood cells. ② Functions of white blood cells White blood cells have the functions of deformation, adhesion, chemotaxis, phagocytosis, digestion and sterilization, and participate in nonspecific immunity of the body. When the body is invaded by bacteria, white blood cells have chemotaxis to small molecular compounds released by skin and bacteria. White blood cells pass through the capillary wall through deformation movement, enter the inflammatory site, and devour a large number of bacteria. White blood cells are in the front line of the body's resistance to microbial pathogens, especially acute suppurative bacteria, which mainly surround the invading bacteria and locally destroy them, prevent pathogenic microorganisms from spreading in the body, and participate in removing immune complexes and necrotic tissues. White blood cells can also devour necrotic cells in the body, including aging and damaged red blood cells. White blood cells often die after swallowing bacteria, called pus cells. ③ Functions and characteristics of platelets A. The number of platelets in normal blood is (100 ~ 300) ×109/L (100 ~ 300,000/μ1). The number of platelets can be increased during eating, physical activity, pregnancy and hypoxia, but it is obviously reduced during the menstrual period of women 1 ~ 2 days. Platelets have the function of maintaining the integrity of blood vessel wall. Platelets play an important role in hemostasis and coagulation. When small blood vessels rupture, platelets immediately adhere to the rupture and gather red blood cells to form thrombus, blocking the rupture and participating in the hemostasis process. When the number of platelets is less than 100× 109/L, it is called thrombocytopenia. When it is reduced to less than 50× 109/L, the fragility of capillary wall increases, and skin mucosal bleeding and purpura appear. Thrombosis is easy to occur when the number of platelets exceeds1000×109/L. Specific adhesion of platelets: After vascular injury, platelets flowing here are activated by vascular subcutaneous tissue and adhere to exposed collagen fibers. Aggregation: Aggregation refers to the process of platelet adhesion. Divided into two stages; The first phase occurs rapidly and is caused by the release of ADP (adenosine diphosphate) from damaged tissues, which is reversible aggregation. The second phase occurs slowly and is caused by the release of endogenous ADP from platelets, which belongs to irreversible aggregation. Release reaction: refers to the process of expelling ADP, 5-HT, catecholamine and other active substances from the body after platelets are stimulated. ADP can cause irreversible aggregation, and 5-HT and catecholamine can contract arterioles and help to stop bleeding. Contraction: Platelets in blood clots have pseudopodes extending into human fibrin network, and blood clots retract through contraction of contractile proteins, becoming solid thrombus and blocking blood vessel wounds. Adsorption: Platelets can adsorb many coagulation factors on its surface, providing phospholipid surface for the coagulation process, so that the coagulation process can occur and proceed. In clinical work, it is sometimes necessary to measure bleeding time and coagulation time to understand the number and function of platelets and whether the type and concentration of coagulation factors are normal. Patients with thrombocytopenic purpura have prolonged bleeding time and normal coagulation time. Hemophilia patients have prolonged coagulation time and normal bleeding time. The nervous system of human body consists of brain, spinal cord and peripheral nerves distributed all over the body. The nervous system controls and regulates the activities of various systems, making the body an organic whole, and it is the dominant system in the body. The nervous system first receives all kinds of information from the internal and external environment with the help of receptors, and then controls and regulates the activities of various systems of the body through the integration of the centers at all levels of the brain and spinal cord, so that the body can adapt to the changeable external environment, adjust the fine balance of the internal environment and ensure normal life activities. Definition and classification of receptors and sensory organs. Receptor is a special structure that the body receives various stimuli in the internal and external environment, and its composition forms are various. The role of receptors is to receive stimuli and convert them into nerve impulses, which are transmitted to the cerebral cortex through the conduction pathways of sensory nerves and central nervous system, thus producing feelings. There are many kinds of receptors, which are widely distributed in all parts of the human body, with different shapes and functions. According to the existing position of receptors and the source of stimuli received, they are divided into three categories. Sensory organ is a special organ composed of receptors and their accessory structures. Such as eyes, ears and other organs. Eight systems of human body (VII) Urogenital system 1, Urogenital system Urogenital system consists of kidney, ureter, bladder and urethra, collectively referred to as urinary system. Kidney is the organ that produces urine; Ureter is a catheter that transports urine to human bladder. Bladder is an organ that temporarily stores urine. Finally, urine is excreted through urethra. The main function of urinary organs is excretion. Excretion refers to the process that all kinds of harmful substances produced during metabolism are not used by the body or transported to the outside world. Part of the discharged substances are the metabolites of nutrients, and the other part is the products formed when aging cells are destroyed. Excrement also includes some unnecessary substances ingested with food, such as water and inorganic salts. Undigested food residues are excluded from the large intestine and do not belong to the category of physiological excretion. There are many ways for human body to excrete, among which the kidney is the most important. The kidney excretes the most excreta in the form of urine, so the kidney is the most important excretory organ of the human body. Other organs with excretory function, excretion is not their main function, but play a certain role in excreting while completing their own functions. For example, although the skin can excrete water, NaCl, urea and other substances through sweating, the main physiological significance of sweating is to strengthen evaporation and heat dissipation and regulate body temperature, rather than excretion. The kidney not only plays the role of excretion, but also plays an important role in regulating the water-electrolyte balance and acid-base balance of the body, which is of great significance to maintaining the steady state of the internal environment of the body. The kidney also secretes bioactive substances such as renin, prostaglandin and erythropoietin. 2. Reproductive system reproduction is an important life activity for human beings to reproduce and continue the reproductive system, including the formation of germ cells, mating, fertilization, implantation, embryo development, childbirth and breastfeeding. The reproductive system consists of a series of organs with the functions of producing germ cells, reproducing new individuals and secreting sex hormones. Although there are differences between male and female reproductive systems, they can be divided into internal genitalia and external genitalia. The internal genitalia is mainly located in the pelvic cavity, and the external genitalia is exposed on the body surface (as shown in the following table). General situation of male and female reproductive system (8) The motor system is 1, and there are 206 adult bones. Each bone has a certain shape, structure and function, so it is an independent organ. According to the position, bones can be divided into skull, trunk bone and limb bone, and limb bone can be divided into upper limb bone and lower limb bone. The chemical composition of bones includes organic matter and inorganic matter. Organic matter is mainly composed of collagen fibers and glycosaminoglycans. Osteocollagen fibers are called bone glue for short, and are arranged in layers; When calcium salt is deposited, a hard layered structure is formed, which is called bone plate. Inorganic substances are mainly composed of calcium salts (such as calcium phosphate and calcium carbonate), which make bones hard and fragile. Organic matter accounts for about 1/3 of adult bone, and inorganic matter accounts for about 2/3. Children's bones contain more organic matter than adults, but less inorganic matter, so they are tough and elastic, not easy to fracture, but less hard and easy to deform. With the increase of age, organic matter gradually decreases and inorganic matter gradually increases. Therefore, the toughness and elasticity of the bones of the elderly are small but fragile; Second, it is easy to fracture. Bone is the largest calcium bank in the body, and 99% of calcium in the human body exists in bone. When blood calcium increases, calcium salt can be deposited in bone; On the contrary, when blood calcium decreases, bone calcium can be dissolved in human blood to adjust the concentration of blood calcium. 2. Bone-to-bone connection device is called bone connection, which can be divided into direct connection and indirect connection according to different connection forms and connecting tissues. Bone is directly connected with bone by dense connective tissue, cartilage or bone, and there is no cavity between them, which is called direct connection, including fiber connection, cartilage connection and osseointegration. It is characterized by a small range of activities or inability to move. Bone to bone is connected by connective tissue capsule, and there is a cavity in the capsule, which is called indirect connection, usually called joint. Joints generally have a large range of motion and produce various movements under the traction of muscles. 3. Muscology The body movements of the human body, including breathing, heartbeat, gastrointestinal peristalsis and the activities of other organs such as blood vessels and lymphatic vessels, are all produced by the contraction of their own muscles. Exercise is one of the main physiological functions of human existence. Muscle tissue is divided into skeletal muscle, smooth muscle and myocardium according to its structure, position and function. The muscles of the motor system are all skeletal muscles. Skeletal muscle is mainly composed of skeletal muscle fibers, which is the dynamic part of the exercise system. Skeletal muscle is attached to bone and spans at least one joint. Under the control of the nervous system, bones move around joints through contraction. Because the movement of skeletal muscle is controlled by consciousness, it is also called voluntary muscle. There are a large number of skeletal muscles, about 600 in the whole body, accounting for about 40% of the body weight. Each muscle has a certain shape, structure, specific neurovascular distribution and performs certain functions, so each muscle can be regarded as an independent organ. In short, the human body is made up of cells, tissues constitute organs, and various organs form various systems with different functions according to their shapes and functions, thus forming the human body. So it can be said that the health of cells determines the health of human body.