What are the four main components of blood and the major function f each component?
1. plasma: About 55% of whole blood is blood plasma, a fluid that is the blood’s liquid medium, which by itself is straw-yellow in color. The blood plasma volume totals of 2.7-3.0 litres in an average human. It is essentially an aqueous solution containing 92% water, 8% blood plasma proteins, and trace amounts of other materials. Plasma circulates dissolved nutrients, such as, glucose, amino acids and fatty acids (dissolved in the blood or bound to plasma proteins), and removes waste products, such as, carbon dioxide, urea and lactic acid. 2. red blood cells (erythrocytes): These contain hemoglobin, an iron-containing protein, which facilitates transportation of oxygen by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. 3. White blood cells: White blood cells are part of the immune system; they destroy and remove old or aberrant cells and cellular debris, as well as attack infectious agents (pathogens) and foreign substances 4. Platelets: Plate