Composition of Blood in animals
Blood is composed of fluid in which the cells and cell fragments are suspended. The fluid portion is known as the plasma‚ and the suspended cellular elements are the – Erythrocytes (RBCs), Leukocytes (WBCs) and Thrombocytes (platelets).
Plasma constitutes about 55 to 70% of the blood volume, while the cellular components account roughly about 30-45% of the total blood. It performs numerous functions that are essential for life and health.
PLASMA
Plasma of blood in animals is the fluid portion of the blood. It is yellow to colourless depending on the quantity, species of the animal and animal’s diet. The plasma colour is golden yellow in dog, colourless or slightly yellow in sheep and goat, while it is highly yellow coloured in horse and cow which is chiefly due to bilirubin‚ and to some extent by the carotene, xanthine and other pigments.
Icterus index
Icterus index is a measure of the yellow colour of the plasma. It is measured by comparing the colour of the plasma with a standard solution of potassium dichromate. Plasma is obtained by adding anticoagulant to whole blood to prevent clotting and centrifuging it for settling down of the cells.
Composition of Plasma
Plasma is made up of water to the extent of 91 – 92%; Solids : 8 – 9%; the solid portion of plasma includes proteins: 6 – 8 g %: Organic and inorganic compounds: 2 – 3 %
| Organic | Carbohydrates : Glucose, Lactate, Pyruvate |
| Inorganic | Macro level : Fe, Cl, SO4, PO4, Micro level : Mn, Co, Cu, Zn, Iodide. |
| Plasma proteins | Albumin, Globulin, and Fibrinogen |
| Non Protein Nitrogenous (NPN) compounds | Urea, Uric acid, Creatine, Creatinine, Salts of Ammonia |
| Lipids | Neutral fat, Cholesterol, Phospholipids, Lecithin |
| Others | Enzymes, Hormones, and Vitamins |
SERUM
In the absence of the anticoagulants, the blood comes out of the blood vessels and gets coagulated to form a blood clot. On shrinking it discharges a clear watery liquid called the serum. Serum is also obtained by collecting the blood without the addition of anticoagulant and allowing it to clot. Later, upon shrinkage of the blood clot the serum is extruded. It differs from the plasma in lacking fibrinogen, prothrombin and other coagulation factors which are involved in blood coagulation.