Human Biology Chapter 3Section 3: The Integumentary System

The Integumentary System

•The integumentary system is the organ system made up of the many different layers of cells that protect you from your outside environments

•The integumentary system includes:▫Your skin▫Your hair ▫Your finger and toe nails

Importance of the Skin•Your skin is the largest organ you have and it

performs several important functions:▫Repels water▫Guards against infection▫Helps maintain homoeostasis▫Allows us to sense our environment

Skin is Complex

Layers of the Skin: Epidermis

• The epidermis is the outer layer of your skin that you can see

• The epidermis contains many protein fibers that give skin its tough protective quality.

•Epidermis cell are formed in the lower layer of the skin and slowly move to the top to replace old cells.

Layers of the Skin: Dermis•The dermis is the

inner layer of skin made up of elastic cells which allows your skin to flex and change shape as you move.

•The dermis contains blood vessel which supply the skin with oxygen and nutrients.

Parts of the Dermis: Sweat Glands

•Sweat glands are found all over the body which release sweat through pores, or openings, on the skin’s surface.

•When we become too warm we sweat to cool off, when water is released it quickly evaporates taking heat with it cooling the body.

Parts of the Dermis: Oil Glands• Oil glands produce oils which moisten your

skin and hair to keep them form drying out. • The oil released also help to water- proof

your skin .• The pores that release the oil (along with

bacteria) are responsible for causing pimples and black heads if they get clogged.

Parts of the Dermis: Hair and Nails•Your hair and nail are both made of dead cells

but both continue to help your body.•Hair on your head protects your scalp from the

sun and keeps your head warm in cool weather; body hair does the same thing but to a lessor degree.

•Your nails simply protect your tender finger and nail beds.

Parts of the Dermis: Sensory Receptors

•Although sensory receptors are part of the nervous system they are located in the dermis.

• The receptors detect heat, cold, pain, touch, and pressure.

•Sensory receptors are made to protect the body: if you feel pain you pull away.

Skin Growth•As you grow your

skin must grow with you.

•Skin growth occurs in the dermis where your new cells divide to replace the old cells.

•Every 2 – 4 weeks your epidermis is completely new.

Healing•When your skin comes in

contact with the outside world injury can occur, if the injury is a minor cut, scrape, or burn your skin can repair it self in a few days.

•However several heat, cold, or major lacerations are more difficult to heal and can require medical attention.

Skin Care•Your skin is just like

any other part of your body and needs to be taken care of.

•You must eat properly and clean it regularly.

• In addition other protections may be needed such as sun block .

The End!!