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Chapter 3 返回目录 BLOOD functions of blood 1.Transportation • O2 and CO2 • nutrients(glucose, lipids, amino acida) • waste products(e.g. metabolites) 2. Homeostasis • Regulation hormones • pH(buffer pairs) body temperature 3. Protection • blood coagulation • Immunity Key points in this chapter: 1.the formation and roles of the osmotic pressure of plasma. 2.the functions of erythrocytes and the factors that effect the production of erythrocytes. 3.functions of leukocytes. 4.the characteristics of platelets and the functions of platelets in the physiological hemostasis. 5.intrinsic and extrinsic pathway of blood coagulation. 6.the anticoagulative functions of antithrombin Ⅲ, heparin. 7.fibrinolysis and diagram the fibrinolytic system homeostasis 1.Components and Physicochemical Properties of Blood 1.1 Components of blood Blood RBC Blood cells(45%) WBC PLT Water(91% of plasma ) Inorganic constituents(1% of plasma) Plasma (55%) e.g. ions:Na+, Cl-, K+, Ca2+ albumin(A) Protein globulin(G) fibrinogen(F) Organic Nutrients: glucose, amino acids, constituents lipids and vitamins Waste products e.g. urea Dissolved gases O2, CO2 Hematocrit (红细胞比容) The volume of red bolld cells as a percentage of centrifuged whole blood. M:40%~60%, F:37%~48%, Blood Volume Blood volume equal approximately to 7%8% of body weight. e.g. a person weigh 70kg, then blood volume is 4.9L, if take the hematocrit to be 45% erythrocyte volume=0.45×4.9L=2.2L plasma volume=4.9L-2.2L=2.7L 1.2 Physical and chemical properties of blood 1.2.1specific gravity of blood » Depending on hematocrit and protein composition » Whole blood:1.050-1.060 » Plasma:1.025-1.035 » Red blood cells:1.090 1.2.2.Viscosity of blood Relative viscosity of whole blood 4-5depending on hematocrit Relative viscosity of plasma 1.6-2.4 related to the protein composition of the plasma 1.2.3. Osmotic pressure of plasma the pressure that must be applied to the plasma to prevent the net flow of water into the plasma is termed the osmotic pressure. (300mmol/L=5330mmHg) (Fig.) The osmotic pressure of a solution depends on the number of solute particles in the solution, not on their chemical composition and size. Osmotic pressure of plasma Crystalloid osmotic pressure concept: Pressure gengrated by all crystal substances, particularly NaCl. role:Important in maintaining fluid balance across cell membranes Colloid osmotic pressure concept:pressure generated by plasma proteins, particularly albumin role: Approximately 25 mmHg, but important in fluid transfer across capillaries 1.2.4.Plasma pH Normal range: 7.35-7.45 Buffer systems in blood NaHCO3/H2CO3 Na2HPO4/NaH2PO4 Pro-Na/Pro Hb Lung and kidney Fig 2. Physiology of blood cells 2.1 Red blood cells(erythrocytes) 2.1.1 Count RBCcount M: (4.0~5.5) ×1012/L W: (3.8~4.6) ×1012/L Hemoglobin concentration M: 120~160g/L W: 110~150g/L 2.1 Red blood cells(erythrocytes) Morphology Biconcave discs Without a nucleus 2.1.2 RBC function ① transport O2、CO2 ②buffering Hb+H+=HHb 2.1.3 Production of RBC (1)Nutritional requirements for erythropoiesis 合成原料 Many vitamins, minerals, and proteins iron 红细胞成熟因子 folic acid, VitB12 intrinsic factor anemia (2) Regulation of erythropoiesis *erythropoietin(EPO) *androgen 雄激素 促红细胞生成素 在哪生成 ? 2.2 White blood cells (Leucocytes) 2.2.1 Types of WBC WBC count Count(×109/L) % Granulocytes Neutrophils Basophils Eosinophils 2.0~7.0 0~0.1 0~0.5 50~70 0~1 1~5 Monocytes 0.1~0.8 1~8 Lymphocytes 0.8~4.0 20~40 WBC Total 4~10 2.2.2 WBC function 1) neutrophil ① protect the body against invading organisms ② eliminate immune complex, dead tissues, aged RBC piapedesis phagocytosis 游走性 2) basophil contain granules ① release heparin (肝素) ② release histamine 组织胺 allergic reaction 3) eosinophil ① restrict allergic reaction induced by basophil and mast cell a. produce PGE, that inhibit active substance released from basophil b. engulf granules released from basophil c. release histaminase ② antagonize parasites 4) monocyte-macrophage ① engulf invading organisms ② eliminate immune complex, dead tissues ③ recognise and kill tumour cell ④ activate lymphocyte ⑤ release cytokines 5) lymphocyte T lymphocyte B lymphocyte Immune function 2.3 Platelets(thrombocytes) • Normal value(100-300) ×109/L • Play an important role in hemostasis(止血) 2.3.1 Physiological properties of platelet (1)Adhesion(粘附) Platelets adhere to the vessel wall at the site of injury (2)Aggregation(聚集) Platelets adhere to one another 纤维蛋白原或 血管血友病因子 (vWF) Inducers of platelet aggregation • ADP low dose 1st reversible phase high dose 2nd irreversible phase • Thromboxane A2(TXA2) 血栓烷素A2 • Collagen 胶原 阿斯匹林 • Thrombin 凝血酶 (3)Release