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Blood

Introduction Physiology is the study of the living things . (from Greek physis = nature; logos = study physiology is concerned with the way the human body works. It is the study of the functions of systems and organs. Organs consist of tissues which are formed of cells. Blood.

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Blood

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  1. IntroductionPhysiology is the study of the living things.(from Greek physis = nature; logos= study physiology is concerned with the way the human body works. It is the study of the functions of systems and organs. Organs consist of tissues which are formed of cells

  2. Blood • A vital fluid which circulates within cardiovascular system. • The total blood volume is about 5600ml in a 70 kg man( 8% of body weight). • It is composed of two main parts -plasma 55% -cellular elements 45%.....RBC’s, WBC’s and platelets

  3. Blood 45 % blood elements Erythrocytes Leucocytes Platelets 55% Plasma - Water - Inorganic substances Na, cl -Organic substances plasma proteins plasma lipids glucose &amino acids

  4. Function of the blood Transport function e.g. glucose, oxygen, carbon dioxide, hormones,………. Defensive function e.g. white blood cells Hemostatic function stoppage of bleeding after injury Homeostatic function what’s homeostasis?

  5. Homeostasismaintenance of constant conditions in the internal environment

  6. Site of hematopoiesis….. in fetus --------Liver & spleen in adult ------- Bone marrow

  7. Plasma It is a yellow clear fluid composed of • Water 90% • Inorganic substances – 0.9% Na+ , Cl- , HCO3 • Organic substances 9.1% -plasma proteins -lipids…triglycerides, cholesterol & fatty acids -other organic substances glucose, amino acids, vitamins, enzymes, waste products 4 Blood gases O2 , CO2 .

  8. Plasma Proteins • albumin • globulins (α, β & γ) • prothrombin • fibrinogen -Concentration…… 7 gm \dl -Site of formation…..? ….liver ( albumin, fibrinogen,prothrombin & 50% of globulins) ….lymphocytes (gamma globulin) -albumin/globulin ratio ??

  9. Albumin-globulin ratio ( A/G Ratio) • Normal A/G ratio 1.2 – 1.6 • It is decreased in 1- liver diseases…… decreased albumin production 2- renal diseases…..albumin is lost in urine

  10. Functions of plasma proteins • Osmotic function…….albumin ( oncotic pressure) • Defensive function……. γ globulins • Blood clotting…..prothrombin and fibrinogen • Blood viscosity………. fibrinogen • Buffer function • Capillary function • transport function…( hormones, metals, drugs…..)

  11. Red Blood CorpusclesErythrocytes / RBC’s Biconcave discs count …. 4.5 - 5.5 million /mm3 structure -semipermeable membrane -hemoglobin ( content and function) -no nucleus Life span ….. 120 days

  12. Hemoglobin( Hb) Hem…..iron containing porphyrin derivatives Globin…protein part formed of 4 polypeptide chains Hb A …..2 α & 2 β (96- 98% of Hb in adult) Hb A2 ….2 α & 2 δ ( 2.5 % of adult Hb) Hb F ….2 α & 2 γ ( Hb of fetus-more affinity to O2 ) Function of Hb 1- transport oxygen from lungs to tissues & carbon dioxide from tissues to the lungs 2- buffering action

  13. Erythropoiesis Definition…formation of new RBC’s Site in fetus -------- Liver & spleen in adult ------- Bone marrow

  14. Factors affecting erythropoiesis • Oxygen supply to the tissues decreased oxygen…….erythropoietin….increased RBC (erythropoietin hormone ? ) 2. Healthy bone marrow (erythropoiesis in adult) 3- healthy liver ( why ? ) storage of Fe, Vit B12, erythropoiesis in fetus 4. Diet……iron, vitaminC, vitamin B12 and folic acid - iron…………………….hemoglobin formation - Vit B12 & folic acid……DNA synthesis & cell division - proteins……………..…globin formation 5. Hormones androgen, thyroid & glucocorticoid hormones stimulates erythropoiesis

  15. Erythropoietin • Glycoprotein hormone • Hypoxia is the main stimulus for its secretion • In adult 85% is formed by the kidney and 15% is formed by the liver • It Stimulates all steps of erythropoiesis and increases the production of RBCs

  16. Hypoxia, cobalt salts, androgens (testosterone), catecholamines, corticosteroids, growth hormone, and thyroxin. production of proerythroblast from the stem cells. Increasing the speed of conversion of one step to the other in the erythroblastic stages. It accelerates the synthesis of Hb. Erythropoietin

  17. Iron • Gastric HCl & vitamin C reduce iron from ferric state to ferrous state • Iron is absorbed in upper small intestine • Iron is found in Hb, myoglobin & ferritin ( storage frorm) Folic acid Essential for DNA synthesis & cell division Vitamin B12 • Essential for DNA synthesis, cell division & metabolism of myelin sheath • It unites with intrinsic factor from the stomach then absorbed from terminal ileum • Deficiency-----macrocytic anemia & neurological symptoms • Treatment by injection of vit B12

  18. Anemia It is a decrease in number of RBCs, hemoglobin content or both. normal RBCs count…….4.5 - 5.5 million/ mm3 normal Hb content……...13.5 15.5 gm/ dl Types 1- normocytic normochromic anemia hemorrhage, hemolytic anemia & bone marrow depression (aplastic anemia) 2-microcytic hypochromic anemia iron deficiency( decreased iron intake &absorption –chronic blood loss) 3-macrocytic hyperchromic anemia vit B112 deficiency absent intrinsic factor, disease of lower ileum, decreased storage in liver disease folic acid deficiency decreased intake, disease of small intestine ,cytotoxic drugs

  19. Pernicious anemia • autoimmune disease of elderly women • Macrocytic anemia and nervous manifestations • caused by absence of HCL & intrinsic factor Polycythemia Increased number of RBC’s Primary polycythemia ( Polycythemia Vera) Increased RBC’s, WBCs & platelets Secondary polycythemia Increased RBCs in hypoxia

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