Introduction Physiology is the study of the living things 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 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

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

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?

Homeostasis maintenance of constant conditions in the internal environment

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

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 .

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 ??

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

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…..)

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

Hem…..iron containing porphyrin derivatives 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

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

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

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

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. Erytheropiotin is a glycoprotein which is normally present in the plasma in low concentration, has a half-life of about 5h. It is produced by the action of an enzyme called renal erytheropiotic factor ( erythergenin) on a circulating plasma protein formed by the liver, erytheropiotin may be secreted directly by the kidneys (From renal glomerular epithelial cells), also about 10 - 15 % of the erytheropiotin is formed by the liver. Erytheropiotin stimulate the bone marrow to produce RBCs through convergen of stem cells to pro-erythroblasts. It stimulates synthesis of RNA and protein in red cell precursors, increasing their rate of mitosis and their maturation time. 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

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

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