BiologyWatch this thread
A person moves from a cold room to a warm room.
Descibe the changes that take place in the skin of thiss person.
The human body is designed to function most efficiently at 37ºC. If you become too hot or too cold, there are ways in which your body temperature can be controlled.Too hotWhen we get too hotweat glands in the skin release more sweat. The sweat evaporates, removing heat energy from the skin.Blood vessels leading to the skin capillaries become wider - they dilate - allowing more blood to flow through the skin, and more heat to be lost.Too coldWhen we get too cold:Muscles contract rapidly - we shiver. These contractions need energy from respiration, and some of this is released as heat.Blood vessels leading to the skin capillaries become narrower - they constrict - letting less blood flow through the skin and conserving heat in the body.The skinThe hairs on the skin also help to control body temperature. They lie flat when we are warm, and rise when we are cold. The hairs trap a layer of air above the skin, which helps to insulate the skin against heat loss.The hypothalamus is the part of the brain which monitors the body's temperature. It receives information from temperature-sensitive receptors in the skin and circulatory system.The hypothalamus responds to this information by sending nerve impulses to effectors to maintain body temperature. For example, if we become too cold, the hair erector muscles contract. This raises the skin hairs and traps a layer of air next to the skin.Skin hairs lying flat and uprightSkin hairs lie flat when we are hot and stand upright when we are coldNegative feedback mechanisms control body temperature. They include the amount of:shivering (rapid muscle contractions release heat)sweating (evaporation of water in sweat causes cooling)blood flowing in the skin capillariesFlow chart showing how the body returns to normal temperature of 37 degrees centigrade. Following an increase in temperature through sweating following a decrease in temperature through shivering.Negative feedback in temperature regulationVasoconstriction and vasodilationThe amount of blood flowing through the skin capillaries is altered by vasoconstriction and vasodilation.Too cold Too hotProcess Vasoconstriction Vasodilation