The body temperature needs to be maintained around 37 degrees Celsius,
if the body gets too hot then there are several mechanisms to help the body
cool down and if the body gets too cold then there are mechanisms to help
the body get warmer.
If the body gets too warm:
Hairs on the body lie flat Sweat is produced from sweat glands, which then
evaporates and removes heat from the skin surface The blood vessels dilate
and therefore blood flows near to the surface and therefore more heat is lost
from the body.
When the body gets too cold Hairs stand up, trapping heat and insulating the
skin No sweat is produced Blood vessels near the skin constrict therefore
minimizing heat loss Your muscles contract quickly and create heat in a
process more commonly known as shivering.