Mammals and thermo-regulation
Mammals are a class of animals which belongs to vertebrates who breathe air and is characterized by the presence of mammary glands in their females and sweat glands and hair in both genders. Humans are also part of this class of animals and as with all animals in this type; they are able to maintain the core body temperature at an optimal level through various mechanisms during extreme temperatures of the outside environment.
The structures helping to maintain temperature
Before describing how mammals maintain their body temperature, let us see what structures support for this functionality. Among the structures, the skin is having many adaptations in maintaining the temperature. Small blood vessels in the skin, the hair, sweat glands will all contribute along with the muscles in the body. Now let us see how these structures function in thermoregulation.
Maintaining the body temperature
-In extreme heat
When the environmental temperature rises beyond a certain level or beyond the body core temperature, the body will take action to prevent becoming over heated. Therefore, the sweat glands will increase its production of sweat which will be secreted to the surface of the skin and therefore evaporate with heat that is on the body surface. This will have a cooling effect to the skin and therefore to the body as well. During such a time, the body hair will be flat against the skin surface and thereby allows the outside air to freely circulate brushing the skin surface and cooling it by taking away the heat absorbed sweat. At the same time, the peripheral blood vessels will also dilate and causes more blood to be brought to the skin surface and thereby facilitate heat to dissipate from the blood to the skin and thereafter to the outside air.
-In extreme cold
If the outside temperature falls, there is a likelihood of the body temperature going down and leading to a hypothermic situation. Thus, in order to avoid such temperature drop, the sweat production would decrease, arterioles will constrict and therefore restrict the heat dissipation from the blood to the skin surface along with erected hairs trapping a layer of air between the skin and the outside environment to prevent heat loss to a certain extent. At the same time, the contractions of the muscles that give rise to shivering will generate heat through mechanical means. Apart from these, the cells itself would be able to generate heat through utilization of energy stores in the body, mostly the brown fat deposits.
As you can see, there are many ways in which a mammal will be able to regulate their body heat and therefore maintain the vital body function intact, including the functioning of hormones and enzymatic structures.
