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Thermoregulation mechanisms and the skin

The skin has an important role in thermoregulation. Look at thermoregulation mechanisms and specifically the skin's role in this article.

The human body uses three mechanisms in thermoregulation (hot and cold):

Efferent responses	Efferent responses are the behaviours that humans can engage in to regulate their own body temperature. Examples include putting on a coat before going outside on cold days and moving into the shade on hot days.
Afferent sensing	Afferent sensing involves a system of temperature receptors around the body to identify whether the core temperature is too hot or cold. Hot thermoreceptors detect a rise above 37.5°C. Cold thermoreceptors detect a drop below 35.8°C. The receptors relay the information to the hypothalamus.
Central control	The hypothalamus acts as the central control, using the information it receives from afferent sensing to produce hormones that alter body temperature. These hormones send signals to various parts of the body so that it can respond to heat or cold in various ways.

The skin (dermis) has an important role in this!

Thermoreceptors in the skin detect changes in skin temperature outside the normal range and send nerve impulses to the hypothalamus. The skin is also part of the body’s response to excessive hot or cold. Let’s look at components of the skin that are useful in regulating the heat of the body.

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This content is taken from
Whitireia New Zealand online course,

Finding the Body’s Balance: Understanding Homeostasis

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Hairs are raised or lowered to increase or decrease the thickness of the insulating air layer by the use of the arrector pili muscle which when contracted causes goosebumps on the skin surface.
Blood vessels in the dermis dilate to promote heat loss (vasodilation) or constrict to reduce heat loss (vasoconstriction).
Sweat glands produce sweat in response to parasympathetic stimulation from the hypothalamus. Sweat cools the body down through the water evaporating from the sweat, transporting heat away from the body.
Fat in the the subdermal layers insulates organs against heat loss.

One of the important features of thermoregulation is the tightening (constriction) and swelling (dilation) of the capillaries in the skin. The constriction of the capillaries helps the body conserve heat, while the dilation of the capillaries helps the body release heat.

In the next two articles, we look at heat loss and heat gain individually.