Homeostasis is important in maintaining a healthy functioning of the body. Enzymes within the body are vitally responsible for speeding up chemical reactions and are often referred to as catalysts. In order to work at their optimum, enzymes need a specific constant temperature within the internal environment of the body to function correctly and reduce denaturing. A healthy human body should have a body temperature of 37∙C, the optimum temperature for enzymes to function. Therefore, the temperature of the body drops below 37∙C, metabolic processes and reactions become slower as molecules have less kinetic energy. If the temperature rises above 37∙C, enzymes stop working and become denatured. This occurs as part of the enzyme called the active site is changed by a rise in temperature and so, certain molecules can no longer bind to the enzyme, and the reaction cannot take place. At higher body temperatures, more sweat is produced by sweat glands that cool the body when it evaporates.
Therefore, blood vessels supplying the capillaries of the skin dilate, vasodilation, in which allows an increased blood flow through the skin’s capillaries which increases energy loss. Heat stroke is often caused by an uncontrolled increase in body temperature. Strenuous exercise during warm weather can cause heat stroke due to an increase in blood flow to the surface of the skin. Exposure to very hot temperatures also increases sweat, dehydration, leading to reduced sweating and an increase in core body temperature. As a result, normal mechanisms for controlling body temperature break down. At lower body temperatures, the increased rate of respiration stimulated by muscles contracting rapidly, shivering, results in some of the energy transferred in respiration, warming the surrounding tissues. Therefore, blood vessels which supply the capillaries of the skin constrict, vasoconstriction, restricting blood flow through skin capillaries which reduces energy loss.
As a result, hypothermia occurs due to the core body temperature falling below 35∙C. In hypothermia, body heat cannot be replaced as fast as it is being lost. Within the body, hormones are responsible for regulating blood glucose, produced in the pancreas in particular areas called islets of Langerhans. If the level of glucose, detected by the pancreas, is higher than normal, a hormone called insulin will be secreted. Insulin then binds to receptor proteins in cell membranes within the liver. This then causes more protein channels to open so that more glucose can enter the cell. Therefore, insulin within the liver will encourage enzymes to convert glucose to glycogen for storage in the liver cells. If however, blood glucose decreases below a normal level, often through doing a lot of exercise, and glucose is being used up, the pancreas secretes another hormone called glucagon, causing the release of an enzyme that breaks down glycogen to glucose, so that the blood glucose level returns to normal.