Definition: Blood is connective tissue composed of plasma (liquid portion) and formed elements (cell and cell fragments).
Function of Blood: Blood is a liquid connective tissue. It has three internal function.
- Transportion: Blood transports oxygen from the lings to the cells of the body and Carbon dioxide from the body cells to the lungs. It also carries nutrients form the GIT to the body cells and hormones from endocrine glands to others body cells. Blood transports heat and waste product to the lungs , kidneys and skin for elimination from the body.
2. Regulation: The circulation of blood help maintain homeostasis in all body fluids .Blood help regulate pH through buffers. It also help adjusting body temperature through the heat absorbing and coolant properties at the water in plasma and its variable rates of flow through the skin, where excess heat can be last from the blood to the environment. Blood osmotic pressure also influence the water contain of the cells, mainly through interaction of dissolve ions and protein.
3. Protection: Blood can clots , from which it protects against excessive loss from the cardiovascular system after an injury except it W.B.C which is present in blood protect against disease by carrying on phagocytosis. Other several types of blood protein, antibodies such of interferon and complements, help protect against disease in a variety of ways.
Physical Properties or Character of blood:
- Blood in Denser an more viscous than water and feels slightly sticky.
- The temperature of the blood is 38˚C about 1˚C higher than oral or rectal body temperature.
- The blood is slightly alkaline pH ranging from 7.35 to 7.45.
- The blood volume is 5 to 6 liter is an average sized adult mate and 4 to 5 liter is an average sized adult female.
- The normal blood volume is contain by the formula body weight.
- The blood is about 55% is plasma and 45% is blood elements.
- The blood volume and osmotic pressure remain constant by negative feed back system.