 Hair
on other mammals serves them to keep them warm. However, the sparse covering of hair on
the human body serves other purposes. It is able to sense insects on the skin before they
are able to sting. The hair on the head serves to control and prevent heat loss as well as
guard against sunlight and physical trauma. Hair is produced by hair follicles in the
skin. These follicles are heavily vascularized and are surrounded by nerve fibers. Goose
bumps occur when small muscles pull the follicles upright producing a bump on the surface
of the skin.
Sweat glands are distributed throughout the skin. Their basic function is to cool the
body. This is accomplished by evaporation. Evaporation of sweat off of the body dissipates
body heat.
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