BLOOD
INTRODUCTION: IMPORTANT POINTS TO REMEMBER Blood volume Specific gravity Viscosity: pH: - 5-6 litres - 1050- 1060. - 3-5 times of water. - 7.4 +-0.05 ; alkaline.
COMPOSITION OF BLOOD A. Cells: Red blood cells / Erythrocytes: 5 million /cumm. White blood cells/ Leucocytes: 4-11x10 3/cumm. Platelets or Thrombocytes: 1.5 -4 lacs / cumm.
B. Plasma: Comprises 55% of the blood volume. Contains: 90% water, 10% solids, Inorganic (1%) -Na, Ca, Cl, HCO3, K, Mg, PO4, Fe3+, Fe4+ Organic (9%) - plasma proteins (8%) Non Protein Nitrogenous substances (2%).
FUNCTIONS OF BLOOD
1. TRANSPORT OF RESPIRATORY GASES: Blood transports oxygen from lungs to tissues and carbon dioxide from the tissues to lungs. 2. TRANSPORT OF NUTRIENTS: Blood conveys absorbed food materials, glucose, amino acids, fatty acids, vitamins and electrolytes from gastrointestinal mucosa to the tissues for utilization and storage. 3. TRANSPORT OF METABOLIC WASTE PRODUCTS: Blood transports the metabolic waste products eg. urea, uric acid, Creatinine to kidney, skin and intestine for their removal. 4. REGULATION OB BODY pH: The blood helps in the regulation of body pH (between pH 7.35 – 7.45) by its buffering action. 5. REGULATION OF BODY TEMPERATURE: Regulation of body temperature 6. BLOOD COAGULATION: Blood protects against its excessive loss from a wound by blood coagulation 7. PLASMA PROTEIN FUNCTIONS: Acts as a reservoir of proteins. 8. Exerts the osmotic pressure which influences of fluid between blood and tissues. 9. TRANSPORT OF HORMONES: Blood transport hormones from the endocrine glands to the other part s of the body where they act.
SERUM When blood is allowed to clot in a test tube, then the clot retracts and the remaining is called serum. SERUM = PLASMA – FIBRINOGEN AND CLOTTING FACTORS. (II, V, VIII)