Blood properties

Blood represents about 8% of total body weight and has an average volume of 5 liters in woman and 5.5 liters in men.

The specific gravity: for whole blood is 1.060, for plasma 1.030 and for blood cells 1.090.

The viscosity of the whole blood is 5 times that of water, while viscosity of plasma is 2 times that of water.

Blood consists of: (a) Fluid part "plasma": representing 55% of blood volume. (b) Cellular elements: representing 45% of blood volume

Functions of blood A) Transport function: 1- Gas exchange = respiratory function = O2 from lung to tissues and CO2 from tissues to lung 2- Nutritive function = carry nutrients absorbed from GIT to liver and other tissues l 3- Excretory function = transport non-volatile waste products of metabolism, such as urea and uric acid, to the kidneys to be excreted 4- Regulatory function = Transports hormones and other substances that regulate cell function to the target tissues.

B) Regulation of body temperature: Plasma absorbs and distributes heat produced during metabolism. Excess heat is removed by redirecting blood flow to the surface of the skin to be lost