Blood Lecture (1) PDF

Blood Lecture (1) BY Prof. Dr. \ Shereen El -Arabi Bdear Professor of Human Medical Physiology  Objectives 1- Functions of the blood. 2-Composition of the blood. 3-Plasma protiens.  Functions of the blood 1-Transportive function 2-Defensive fun...

Blood Lecture (1) BY Prof. Dr. \ Shereen El -Arabi Bdear Professor of Human Medical Physiology  Objectives 1- Functions of the blood. 2-Composition of the blood. 3-Plasma protiens.  Functions of the blood 1-Transportive function 2-Defensive function 3-Regulatory function +  Functions of the blood 1-Transportive function : -It transports:- 1-Respiratory gases:- - O2 from lung to tissues - CO2 from tissues to lung 2- Nutrients from G.I.T to all tissues 3- Waste products from tissues to organs of excretion? 4- Heat from deep tissues to skin to be lost. 5- Transport heat to hypothalamus to deal with it 6- Hormones from endocrine glands to target tissue  2- Defensive function :- a-Against Bactria by white blood cells (Wbcs) through : 1- Phagocytosis. 2- Produce antibodies against F.B. b- Against hemorrhage by formation of blood clot to prevent blood loss.  3- Regulatory function: A-Temperature. B- Hormones by feedback mechanism C- Body fluid. D- PH. by its buffer effect.  Composition of blood 1-Fluid part 55 % consisted of : Plasma. 2- Cellular part (cells) 45 % consisted of: * Red blood corpuscles (Rbcs) * White blood cells (Wbcs) * Platelets  Plasma proteins Albumin Globulin Fibrinogen Prothrombin - Value 3.5-5 gm% 2.3-3.5 gm% 200-400mg % 10-15 mg % - M.W 70.000 150.000 340.000 69.000 -Synthesis Liver Liver→1, 2, 1, B2, Liver Liver in presence of vit K γ types - Main -Transporter -Carrier -Viscosity Act as clotting factor II function -Osmotic pres. -Defensive Bl. Clotting(factor I) regulation  Functions of plasma proteins:-  1-Used by tissues as nutrient during prolonged starvation.   2- Albumin is the main protein responsible for osmotic pressure (O.P ). O.P of plasma protein is about 28 mm Hg. By its (O. P) it regulates the volume of blood, tissue fluid and urine.  Functions of plasma proteins:- 3- Fibrinogen is the main protein responsible for blood viscosity. By its viscosity, it affects peripheral resistance, blood pressure and blood flow. 4- Most of clotting factors are plasma protein. 5-Have defensive function by γ globulins.  Functions of plasma proteins:- 6-They carries important material and prevents its loss in urine e.g Iron, thyroid hormone.  7-they affect capillary permeability as the pores in capillaries is partially blocked by plasma proteins.  Functions of plasma proteins:- 8-they has buffer function. 15 % of buffering power of blood is due to plasma protein 9-Certain plasma proteins have specific function eg. Enzymes.  Hypoproteinemia -Marked decrease in plasma protein - Causes of hypoproteinemia: 1-Decreased intake of protein. e.g. as in malnutrition 2-Decreased absorption of protein e.g. as in malabsorption. 3-Decreased formation of protein e.g. as in liver disease. 4- Increased loss of protein e.g. kidney disease. 5-Congenital deficiency of protein.  Manifestation of Hypoproteinemia: 1- Edema and acities due to decrease osmotic pressure of plasma proteins as a results of decreased albumin. 2- Bleeding tendency: due to decrease clotting factors. 3- Susceptibility to infection: due to decrease γ globulins.  Red blood corpuscles (Rbcs) ( Erythrocytes) Number: – 5.5 – 6.5 million / mm3 in ♂. - 4.5 – 5.5 million / mm3 in ♀. Site *Why do females have less RBC? 1-Menstrual blood loss. 2-Stimulatory effect of testosterone on erythropoiesis in males.  Site of formation (Erythropoiesis): -In adult: it is formed in bone marrow of membranous bones e.g. sternum, ribs , vertebrae , bones of the skull , ends of long bones. e.g. femur - Life span of Rbcs 120 days - Destructed in spleen - The end product of its destruction is bilirubin  Shap and volum of RBCs -Biconcave disc - - Non nucleated - Thickness: peripheral 2 μm Central 1 μm - - Diameter: 7.2 μm - Volume: 80 – 90 mm3 Shaped as biconcave disks. *Advantage? -Great surface area of the biconcave disks facilitates: 1-Gas exchange. 2-Deformation in narrow capillaries. 3-Prevent their rapture in case of hydration. RBC lack a nucleus and most organelles. *Advantage? -Increase their carrying capacity to gases RBCS Contents  - 60% H2O. - 34 % hemoglobin (HB). -Enzymes e.g carbonic anhydrase. - Electrolytes e.g K+, Mg++ Hemoglobin is formed of: 1- Four Haem; each one is formed of Iron + pigment (protoporphyrin) 2- One globin is formed of 4 polypeptide chains. Functions of Hb 33 Hb+ O2  Oxyhemoglobin. ( Main ) Hb+ CO2  carbaminohemoglobin. Hb+H+  HBH+ (buffer) The functions of Rbcs 1 -Transport of respiratory gases (O2 to tissue, CO2 to lung). *Each 1 gm of HB can carry 1.33 ml O2 and iron is kept in ferrous 2-Buffer function Concentrations of HB -13-17 gm / dl in ♂ -12 -15 gm / dl in ♀ HB: gives the blood its red color. Thank you