Blood Physiology PDF

Blood Physiology Dr. Nermeen Bastawy Physiology Department Faculty of Medicine, Cairo University 1- Concerning the synthesis of plasma proteins: a. All types are formed by the liver only b. Albumin, globulins and 50% of fibrinogen are formed by liver c. Gamma globulins are forme...

Blood Physiology Dr. Nermeen Bastawy Physiology Department Faculty of Medicine, Cairo University 1- Concerning the synthesis of plasma proteins: a. All types are formed by the liver only b. Albumin, globulins and 50% of fibrinogen are formed by liver c. Gamma globulins are formed by plasma cells Gamma globulins are released from T-lymphocytes 2- Concerning plasma proteins: a. They include clotting factors b. Globulins are formed mainly in the liver c. Fibrinogen has the highest concentration d. Albumin has the largest molecular weight e. Albumin is mainly formed by the reticulo-endothelial system 3- All the following about plasma proteins are correct, except: a. Are formed in the liver and kidney b. Deficiency produces edema c. Prevent the loss of iron and vitamin B12 in urine d. Are sources of tissue proteins 4- Regarding plasma all is correct, except: a. Contains antibodies b. Its normal content of proteins is 7.4 mg/dl c. It clots on standing d. Is part of ECF 5- The plasma protein with the lowest molecular weight is: a. Albumin b. Beta- globulin c. Gamma-globulin d. Transferrin 6- Albumin/Globulin ratio: a. Normally equals 1.2: 1.6 b. Is higher in liver disease c. Is increased in albuminuria d. Increased in infections  RED BLOOD CORPUSCLES “ERYTHROCYTES” No nuclei, no mitochondria Biconcave → ↑ SA & Flexibility M: 5.4 million/mm3 F: 4.8 millions/mm3 Higher in: Newborn, Athletes, High altitude due to relative hypoxia Lower in: old age Hb conc. g/dl 13-14 15-16 19  Lifespan & fate of RBCs Lifespan : 120 days Site of hemolysis: Spleen Iron is stored as ferritin  Erythropoiesis Def. formation of new RBCs Site: Fetus: liver & spleen Children: red marrow of all bones Adult: flat axial bone: vertebrae, skull, ribs clavicle, scapula, and pelvis Factors affecting erythropoiesis: 1. O2 supply & erythropoietin (EPO) 2. Healthy organs: bone marrow, liver, kidney 3. Hormones & Diet 1. Oxygen supply to tissues & role of EPO examples of hypoxia: 1. High altitudes 2. Athletes 3. Newborn 4. Hemorrhage 5. Lung & heart diseases Hypoxia stimulates release of EPO from kidney and liver →stimulates erythropoiesis in bone marrow  85% Hypoxia Alkalosis Androgens Cobalt Drugs  Patients with renal failure develop severe anemia as liver cannot compensate CKD : Chronic kidney disease  2. Healthy Organs Causes of bone marrow Destruction or depression? X-ray, irradiation, toxins, infections, malignancy, unknown → Aplastic anemia kidney liver Form 85% of EPO Form 15 % EPO Form globin protein Stores iron & vit B12  3. Hormones and Diet Hormones: Erythropoietin, Thyroxin, Androgens, Glucocorticoids Diet: Proteins, Iron, Vitamins (vit C, B12 & Folic acid) & Trace elements: copper, zinc, cobalt, selenium 1- Erythropoiesis: a. Occurs in the liver during the first 5 years of life b. Above 20 occurs in the bone marrow of all bones c. Is affected by vitamin K deficiency d. Is stimulated at high altitude e. Is more stimulated in females than males 2- Erythrocytes: a. Are rigid biconcave cells b. Have a life span of 180 days c. Are responsible for the major part of blood viscosity d. Decrease in females due to menstrual cycle 3- A 36-old-man with CKD has severe anemia. Which of the following is the most appropriate therapy? a. Erythropoietin b. Ferrous sulphate c. Folic acid d. Vitamin B6 4- Concerning erythropoiesis, one is not correct: a. It means formation of new blood cells b. It occurs in the liver and spleen during fetal life c. Erythropoietin hormone is secreted mainly by the liver d. It is inhibited after exposure to atomic radiation.  Iron absorption Upper small intestine HCL enterocytes Ferric (Fe+3) →→ Ferrous (F+2)  Vit. B12 (Cyanocobalamine, Maturation Factor, Extrinsic Factor) Sources: animal Stomach: intrinsic factor Absorption: Lower ileum Storage: liver Deficiency causes: Failure of absorption decrease in diet e.g. vegetarians Vitamin B12 (Cyanocobalamine, Maturation Factor, Extrinsic Factor) Importance: Synthesis of DNA Myelination of nerves Deficiency leads to: Macrocytic anemia & Neurological manifestations  Iron Vit.B12 Absorption Upper SI (dued) Lower SI (ileum) Role of HCl Intrinsic factor stomach Decrease Common Rarely* intake Effect of Microcytic anemia Macrocytic anemia deficiency * Except in vegetarians  Folic acid Sources: Fresh food Deficiency causes: Deficient in Diet Pregnancy Malabsorption Antifolate cytotoxic drugs Deficiency → Macrocytic anemia  Types of anemia Microcytic Normocytic Macrocytic hypochromic normochromic (megaloblastic) Iron def. anemia ↓ Iron Acute Hge: ↓ Vit. B12 -- intake in diet Hemolysis gastrectomy, absence of intrinsic ++ demand as in Aplastic factor (pernicious anemia), and distal small intestine diseases pregnancy & children -- absorption Anemia Chronic hemorrhage: ↓ folic acid Parasite infestations Peptic ulcer antifolate cytotoxic drugs as methotrexate. Piles Excessive menstruation  Hemolytic anemia Intrinsic disorders Extrinsic disorders Incompatible blood transfusion Erythroblastosis fetalis “Rh incompatibility,” Bacterial toxins, Chemicals or poisons Drugs Hereditary spherocytosis Sickle cell anemia (Hb S) ↓ G-6-PD enzyme (Favism) Thalassemia Hemolytic Jaundice Autoimmune reaction against the parietal cells of stomach → macrocytic anemia & nervous manifestations 1- Vitamin B12: a. Deficiency produces normocytic anemia. b. Needs gastric HCl for its absorption c. Is absorbed from the upper part of the small intestine d. Is needed for nuclear maturation and cell division. e. Is stored in the bone marrow 2- Iron: a. Is absorbed as ferrous (Fe2+) iron by a passive process b. Is decreased in acute blood loss c. Is stored in the liver in the form of transferrin d. Needs vitamin C for absorption e. Deficiency produces pernicious anemia PLATELETS (THROMBOCYTES) ✓Small, non-nucleated, granulated bodies ✓300,000/mm3 ✓Thrombocytopenia # thrombocytosis ✓Source: Bone marrow  Hemostasis Stoppage of bleeding from an injured blood vessel 1- vasoconstriction (VC) 2- platelet plug 3- clotting (fibrin threads)  Stages in platelet plug formation ▪ Platelets don’t adhere to normal endothelium ▪ Platelets adhere to injured endothelium → active  Blood Clotting Clotting factors are inactive Plasma Proteins Synthesis in liver Some Need vitamin K 2 Mechanisms for Clotting: Intrinsic Pathway & Extrinsic Pathway  VIVO VITRO VIVO ONLY SLOW RAPID 1-6 min 15 s Simultaneously All steps need Ca ions except activation of factors XI,XII  The Clotting Mechanism All steps need Ca ions except activation of factors XI,XII  2 Mechanisms for Clotting Intrinsic Pathway Extrinsic Pathway Slow 1-6 min Rapid 15 sec Vivo & Vitro Vivo only VIII, IX,XI,XII, Ca++ III, VII, Ca++ Activation of clotting factor X → Formation of thrombin & fibrin  Anticlotting Mechanisms A. General factors: 1.Smooth endothelium 2.Rapid blood flow 3.Heparin B. Specific factors: 1. Prostacyclin (PGI2): secreted from normal endothelium and decrease platelets reactions 2. Antithrombin III: inhibit factors 9,10,11,12. This is facilitated by heparin. 3. Fibrinolysis by plasmin and other proteins  In Vitro Anticoagulants Na+ citrate: deionize Ca++ Na+ oxalate: precipitate Ca++ Silicon tube Heparin EDETA  In Vivo Anticoagulants Heparin Dicumarol Origin Mast cells & Plant basophils Action Help Anti- Competitive inhibition thrombin III with vitamin K (1972) Site of action In vivo & vitro Only in vivo. Onset/ duration Rapid & short Slow & long Administration Injection Oral Antidote Protamine sulphate Vitamin K  Hemostasis Disorders Thrombocytopenic Purpura Platelets < 50 000/mm3 Subcutaneous hemorrhage  Vit K Deficiency Fat soluble vitamin synthesized by intestinal flora Need bile for absorption Needed for formation of factors: 1972 ↑ Clotting time Vitamin K deficiency: a. Absent flora (newborn) b. Antibiotics long use c. Biliary obstruction d. Dicumarol treatment e. Diet Hemophilia X-linked recessive severe bleeding after mild trauma A (8) → 85 % Types B (9) C (11)