Blood Physiology PDF

Blood physiology * Blood is a red fluid tissue. * Blood volume is 5 liters in adults. Blood composition   1- Fluid part 2- Cellular elements “Plasma”...

Blood physiology * Blood is a red fluid tissue. * Blood volume is 5 liters in adults. Blood composition   1- Fluid part 2- Cellular elements “Plasma” It represents 55% of blood volume It represents 45% of blood It is composed of : volume a) Water (90%) Three types of cells are b) Dissolved substances (10%) present   a) Red blood cells Organic Inorganic (RBCs) (9.1%) (0.9%) 5×106/mm3 (7.1%) (2%) - Na+ Plasma Nutrients - K+ b) White blood cells proteins Waste - Ca2+ (WBCs) Products - Mg2+ 4000-11000/mm3 O2 & Co2 - Cl- Hormones - HCo3- C) platelets - Po4- 150.000-400.000/mm3 - So4- Blood functions:- 1- Transport function Respiratory function The blood transport O2 from the lung to the tissues and Co2 from the tissues to the lung. Nutritive function The blood transport nutrients absorbed from gastrointestinal tract (GIT) to the tissues. Excretory function: The blood transport waste products from the tissues to the kidney. Regulatory function The blood transport hormones from glands secreting it to its target organs 2- Regulation of body temperature The blood flow to the skin increases in hot weather to increase heat loss and decrease in cold weather to decrease heat loss. 3- Hemostatic function Stoppage of bleeding from injured vessel this is done by: 1- Platelets. 2- Clotting factors. 4- Defensive function Attacking invading organism this is done by: 1- White blood cells 2- Antibodies Plasma proteins Albumin globulin Fibrinogen    Osmotic pressure Defense antibodies Hemostasis (clothing factor) Transport carrier Blood viscosity Cellular elements Red Blood cells Male: 5-6×106/mm3 * Count: 4-6 million / mm3 Female: 4-5×106/mm3 Functions: 1- Blood viscosity 2- Contains hemoglobin which carry O2 from lung to tissues and carry Co2 from tissues to lung (respiratory gas transport) Synthesis of RBCs = Erythropoiesis Site: Bone marrow Factors effecting erythropoiesis:  1- Tissue oxygenation (erythropoietin) 2- Dietary substances (protein, iron, vitamins) 3- Trace elements (copper and cobalt) 4- Hormones (stimulated by testosterone, growth hormone, thyroxin) 5- Healthy bone marrow. 6- Healthy liver 7- Healthy kidney Hemoglobin (Hb) * Present inside RBCs and normal content is 15 gm/dl. Fate: N.B Heme Globin    Iron Bilirubin Aminoacid pool    Re-utilization Excreted in bile Re-utilization Anemia It is decrease in RBCs count and/or decrease in Hb content. Types: 1- Deficiency anemia: Iron (Fe) deficiency anemia, vitamin B12 deficiency anemia, or folic acid deficiency anemia. 2- Aplastic anemia: No bone marrow synthesis of RBCs. 3- Hemorrhagic anemia: due to blood loss. 4- Hemolytic anemia: due to destruction of RBCs. 5- Anemia of chronic kidney disease: No erythropoietin hormone. Blood groups (Blood types): 1) ABO system Cell membrane contains antigens (A and/or B or none) so there are blood groups A B AB O - Blood group (O) is called universal donor - Blood group (AB) is called universal recipient 2) RH system Cell membrane contains Rh antigen or not so there are blood group Rh +ve Rh -ve White blood cells Function: Defense function and immunity Classification: it is classified according to presence or absence of granules and the staining characteristics of their cytoplasm into:- 1- Granulocytes: have large granules in their cytoplasm (neutrophils, eosinophils, and basophils). 2- Agranulocytes: do not have granules in their cytoplasm (lymphocytes, and monocytes). Platelets Hemostasis Definition: It is stoppage of bleeding from injured blood vessel It requires platelets and clotting factors. Mechanism of natural hemostasis: 1- Local vaso-constriction. 2- Formation of platelet plug. 3- Formation of fibrin clot.