Blood Lecture Notes (PDF)

General Physiology-Health sciences Blood Physiology Blood Composition 1) Plasma (55%) 2) Blood Cells (45%) 3 Red Blood Corpuscles (RBCs) 4  Red Blood Corpuscles (RBCs) Erythrocyte count: ▪ Males:...

General Physiology-Health sciences Blood Physiology Blood Composition 1) Plasma (55%) 2) Blood Cells (45%) 3 Red Blood Corpuscles (RBCs) 4  Red Blood Corpuscles (RBCs) Erythrocyte count: ▪ Males: 5.0-5.5 million/mm3 ▪ Females:4.5-5.0 million/mm3 ▪ Newborn: increased ▪ Child and old age: decreased ▪ Persons living at high altitude: increased  Red Blood Corpuscles (RBCs) Shape : Circular, Non-nucleated, Biconcave discs  Red Blood Corpuscles (RBCs) ❑Structure of RBCs: RBCs are not true cells, because they have no nuclei, so called corpuscles. b) Contents: ❖Hb (34% of RBC) is the main constituent. ❖K+ is the chief intracellular cation. ❖ Carbonic anhydrase enzyme helps CO2 transport, ❖ No mitochondria, so they obtain energy from anaerobic glycolysis  Functions of RBCs 1) Functions of cell membrane: a) It has a large surface area that allows easy diffusion of gases. b) Plastic → allow RBCs to be squeezed in small capillaries without rupture of it. c) It keeps Hb inside RBCs → prevent its loss in urine. 8  Functions of RBCs 2) Functions of Hb: a.Transport of O2 from lung to tissues by hemoglobin. b.Transport of CO2 from tissue to lung by help of carbonic anhydrase c. Hb is an excellent acid - base buffer 3) Blood viscosity: RBCs share in production of blood viscosity, which maintains arterial blood pressure. AS Biology, Cell membranes and 9 Transport  Haemoglobin Def. It is iron containing red pigment which is present inside RBCs. Hb structure: consists of heme and polypeptides Value: o in adults males→ 14-18 g/dL o in adults females→ 12-16 g/dL o in newborn → 18 g/dL o in children → 12 g/dL 10  Red Blood Corpuscles (RBCs) Life span and fate of RBCs Life span of RBCs is about 120 days 11  Erythropoiesis Def., It is the process of new RBCs production Sites : Red bone marrow 12 Factors Affecting Erythropoiesis Tissue Oxygenation Diet Healthy (proteins, Organs (liver, Erythropoiesis and bone vitamins and Minerals) marrow) Hormones (thyroid, androgens and cortisone) 13 1)Tissue Oxygenation Hypoxia (e.g. high altitude, athletes and hemorrhage) Increase RBCS formation via erythropoietin (EPO) secretion (90% from kidneys and 10% from liver) a) EPO ++ transfer of stem cells in bone marrow to proerythroblasts b) EPO accelerates all the stages of development of mature RBCs from proerythroblasts 14  2) Healthy Bone Marrow Healthy bone marrow RBCs formation Destruction of bone Deficiency of all marrow by blood cells (Aplastic irradiation, or drugs Anemia) 15  2) Healthy Liver Healthy Liver RBCs formation 1. Store Fe and Vit B12 2. Globin part of Hb 3. 10% of erythropoietin 16  3) Hormones Thyroid hormones Hormones Glucocorti Androgens coids 17  Nutritional factor ❑Proteins of high biological value (contain more essential amino acids) that present in liver, kidney and muscle are essential for erythropoiesis  Minerals 1.Iron: Important for the formation of Hb 2. Copper:Cofactor in Hb synthesis. 3. Cobalt; Cofactor in Hb synthesis.  Vitamins ❑ All vitamins are needed for erythropoiesis Vitamins B12 and Folic Acid Deficiency of Vit Megaloblastic B12 or Folic acid anemia  Anemia Def. ▪ It is a ↓ in O2 carrying capacity of blood due to deficiency of Hb which can be caused by either ↓ed number of RBCs or too little Hb in the cells.  Anemia Blood Loss anemia Aplastic Hemolytic anemia Anemia anemia Megaloblastic anemia 22  1) Blood Loss Anemia a) Acute blood loss anemia: Normocytic Haemorrhage Normochromic Anemia RBCs are of normal shape, size and hemoglobin content 23  1) Blood Loss Anemia b) Chronic blood loss anemia: Chronic loss of Iron Chronic bleeding e.g. peptic ulcer Microcytic hypochromic anemia RBCs are of small size and little Hb content 24  2) Aplastic Anemia Destruction of BM by 1. Irradiation 2. Tumors Aplastic Anemia 3. Anticancer drugs 25  3) Megaloblastic Anemia Due to deficiency of either, vit B12, folic acid or the intrinsic factor from the stomach mucosa. 26  4) Hemolytic Anemia ❑Caused by excessive destruction of RBCs due to different abnormalities that make the cells more fragile. e.g. sickle cell anemia and thalassemia or incompatible blood transfusion. 4) Hemolytic Anemia  Polycythemia It means increased number of RBCs. It may reach 6-8 millions/mm3 29 THANK YOU