Adrenalin - a person's body produces adrenalin when he is angry frightened or challenged or when he needs to be functioning at maximum efficiency to meet some sort of stress. Adrenalin is a hormone a substance which acts upon tissues and organs. It is secreted in the adrenalin glands which lie like a pair of pyramid shaped caps one on top of each kidney. Each gland has two parts the outer shell or cortex and the inner core or medulla. The adrenal hormones come from the medulla and are released into the bloodstream. They stimulate the liver both to release its sugar and to speed up its manufacture for muscular action. They also contract blood vessels, diverting blood from the skin and raising the pressure at which it is pumped through the brain and lungs and muscles. The heart and pulse quicken the breathing speeds up the body heat rises and muscular fatigue is postponed. At the same time the ability of the blood to coagulate in the event of the person being wounded is increased. This series of defence reactions occurs almost immediately. Adrenalin released by the glands is reinforced by more hormones produced at the sympathetic nerve ends. A hormone produced in the brain called serotonin stimulates the transmission of nerve impulses.
No comments:
Post a Comment