The Skin

Skin

• Made of three layers– epidermis– Dermis– hypodermis

Epidermis

• Outer, thinnest layer– Outermost cells of skin

are dead and rub off when you touch anything

– New cells constantly produced at base of epidermis

– Cells produce melanin, which is a pigment that protects your skin and gives it color

Dermis

• Middle layer– Thicker than epidermis– Contains blood vessels,

nerves, muscles, oil, sweat glands

Hypodermis

• Fatty layer– Insulates the body

Functions of Skin

1. Protection forms a protective covering over body that prevents injury1. Disease causing pathogens cannot pass through skin2. Prevents excess water loss

2. Sensory response nerve cells in the skin detect and relay information to brain

3. Formation of Vitamin D helps body absorb calcium4. Regulation of body temp

1. Blood vessels in skin help release or hold heat2. Perspiration from sweat glands eliminate excess body heat by

evaporation

5. Elimination of wastes (through sweat glands)

Skin Injuries

• When injured, skin produces new cells and repairs tears– Bruises happen when tiny

blood vessels beneath skin burst and leak into surrounding tissues

– When you have a cut, a scab forms to prevent bacteria from entering your body

– Skin cells grow beneath the scab and fill in gap of torn skin

Severe Injuries

• Doctors able to repair severe skin damage– Skin grafts pieces of skin

cut from one part of a person’s own body and moved to injured area

– Sometimes use cadavers to prevent infections until a victim’s skin heals

– Can also grow large sheets of epidermis from small pieces of victim’s healthy skin