L3 Practical Biology- Blood Composition PDF

Blood Blood is a fluid tissue suspended in the watery plasma which is continuously circulating inside the blood vessels by the pumping action of the heart. Blood RBCs WBCs Platelets Granulocytes Ag...

Blood Blood is a fluid tissue suspended in the watery plasma which is continuously circulating inside the blood vessels by the pumping action of the heart. Blood RBCs WBCs Platelets Granulocytes Agranulocytes Neutrophils Basophils Monocytes Eosinophils Lymphocytes Composition of blood 1- Cells: 45% of blood volume. a- Red blood corpuscles (RBCs) or erythrocytes. Number: 5.4 million/mm3. Function: Carriage of O2 and CO2. b- White blood corpuscles (WBCs) or leucocytes Number: 4000 – 11000/mm3. Function: Defense against bacteria. c- Platelets or thrombocytes Number: ¼ - ½ million/mm3. Function: Blood clotting. 2. Plasma: 55% of blood volume: Plasma is the straw-colored liquid in which the blood cells are suspended. Composition of blood plasma Component Percent Water ~92 Proteins 6–8 Salts 0.8 Lipids 0.6 Glucose (blood sugar) 0.1 a. Water 92% b. Plasma protein 6–8%: Albumin, globulins and fibrinogen c. Organic substances 2%:  Waste materials e.g. urea.  Nutritive materials e.g. glucose.  Regulatory materials e.g. hormones and enzymes. d. Inorganic substances (1%):  Cations e.g. Ca++, Mg++, Na+ and K+.  Anions e.g. C1- and HCO3-. Red blood corpuscles (RBCs) or erythrocytes  RBCs are non-nucleated circular biconcave discs.  The most numerous types in the blood.  They do not contain mitochondria because of O2 does not consumed.  The bone marrow is produced 1011 RBCs each day.  295,200,000,000 RBCs were died and scavenged by the liver each day. Did you imagine how many cells die each second?  RBCs can never divide.  They live about 120 days and then are ingested by phagocytic cells in the liver and spleen.   Normal count  5.4 millions of these cells per cubic millimeter (mm3) which is the same as a microliter (µl) in adult males and non- menstruated females.  Average 4.8 millions/mm3 in adult menstruated females. Sites of formation  The bone marrow is responsible for RBCs formation. White blood corpuscles (WBCs) or leukocytes.  WBCs are much less numerous than red (the ratio between the two is around 1:700).  Have nuclei.  Participate in protecting the body from infection.  Consist of lymphocytes and monocytes with relatively clear cytoplasm, and three types of granulocytes, whose cytoplasm is filled with granules. 1. Granulocytes  These have granules in their cytoplasm.  They are formed in the bone marrow. a. Neutrophils (microphages): They are highly phagocytic and represent the most abundant 50-70% of the leucocytes. (40-60). b. Eosinophils:  They may absorb histamine released in allergic conditions.  They represent very low percentage 2-4 %.  They have a limited phagocytosis, increases in parasitic infection. c- Basophils:  They are related to production and carriage of histamine and heparin.  They are slightly phagocytic cells.  They represent 0.5-1% of the leucocytes.  Increased in allergy and hypersensitivity. 2. Non granulocytes  These have no granules in the cytoplasm.  Their round nucleus is large.  They are formed in the lymphatic tissues. a- Lymphocytes: There are three types of lymphocytes β, T and NK cells.  Form 20-40% of total leucocytes.  Function: i. Formation of antibodies. ii. Can change into highly phagocytic monocytes. b- Monocytes:  Represent 3-8% of total leucocytes. Function: i. They are highly phagocytic. ii. They leave blood to connective tissue where they change to macrophages engulfing bacteria. Figure (22): Red blood cells. Figure (23): White blood cells.