Human beings, like other animals, are endothermic; hence, able to control its body temperature keeping it at a constant level in a process called thermoregulation. There are different mechanisms that help in regulating the body temperature. Different parts of the body take part in thermoregulation include the skin, hypothalamus in the brain, muscles and the thyroid gland.
Thermoreceptors, which are sensory receptors in the body, detect change in the body temperature. There are two sets of receptors; those in the hypothalamus and the skin, which monitors core body temperature and external temperature respectively. Thermoreceptors send signals to the hypothalamus, which secretes pituitary hormone releasing factors (Soderquist, 2002). This way the hypothalamus controls the body response to temperature. People voluntarily respond to increased body temperature by such behavior as shading, drinking water or fluids, taking off cloths, or even fanning. When the receptors detect high temperature, signal goes to the hypothalamus, which initiates response. A message sent to the skin through nerve gives different responses as follows. Increased production of sweat in the sweat glands to increase evaporation from the skin, thus, giving a cooling effect. Blood vessels dilate to increase loss of heat to through the skin by conduction. The erector pili muscle also relaxes letting the skin hair relax and lie allowing better air circulation in the immediate area above skin (Marino, 2008). There is no shivering to contract the muscle when the temperature is high.
When the temperature drops below the normal range, a person response voluntarily by: putting on thick and warm clothing, going to warm place, taking hot food or by doing exercise among other heat generating responses. Inside the body, the receptors detect low temperature and a message goes to the skin to give different involuntary responses. Sweat glands do not produce any sweat when it is cold. Blood vessels contract (vasoconstriction) to prevent heat loses through the skin by conduction. The contraction of the erector pilus’s muscle raises the hair on the body, which subsequently capture insulating thin film of air (Russell, 2008). Sometimes, there is involuntary shivering leading to contraction of muscle thereby producing heat. Low body temperature triggers the production of Thyroid Stimulating Hormone (TSH), which induces thyroid gland to produce large amounts of thyroid hormones (T3 and T4), which increases metabolic rate (Morrison, 2007). Increased metabolic rate raises the body temperature subsequently.
In conclusion, body temperature within the normal range because high temperature denatures proteins. Skin (peripheral) thermoreceptors detect change in the temperature of the environment while hypothalamic thermoreceptors detect change in cells’ environment. The response to change uses feedback mechanism of returning the imbalance to normal.