Structure and Function of the Skin
Hair
Is a shaft made of dead cells covered by a cuticle.
Formed by multiplication of cells in the Malpighian layer which are then pushed into the hair follicle as dead material at the base (dermal papilla). The continuous addition of new cells at the base of the hair causes it to grow.
The hair follicle is supplied with sensory nerve endings which respond to movement of hair.
Hair erector pili muscle contraction and relaxation causes the hair to stand or lie flat respectively leading to thermoregulation.
Sebaceous glands
Open their ducts into hair follicles.
Secrete an oily substance called sebum which:
- Keeps the epidermis and hair supple/water repelling property.
- Has antiseptic properties against bacteria and fungi.
Nerves
Detect changes in the environment (stimuli) such as pain, touch, heat and cold.
Carry the information to the brain which in turn cause the organism to respond appropriately.
Subcutaneous fat layer
Is a layer of cells beneath the skin filled with fats and oils called adipose tissue.
It insulates the body against heat loss.
