1. Integumentary System Consists of Largest organ of the human body the
skin
hair
glands
nails
Largest organ of the human body the
Skin accounts for 16% of the bodies mass!

2. Functions Protection—first line of defense Communication
Disease (micro-invaders)
Loss of fluids
Physical injury
UV Light
Regulation of Temp
Sweat
Insulation
Blood supply
Communication
Receptors
Hot/cold
Pain
Touch

3. Functions Vitamin D Production Calcium absorption Excretion of Wastes
For bones
For muscle contraction
Excretion of Wastes
sweat

4. The Layers of the Skin Skin Cross Section Epidermis Dermis Dermis
Subcutaneous
(Hypodermis)

5. The epidermis is divided into two layers, dead and living cells.

6. Epidermis
Living cells of the epidermis replicate, pushing their way towards the surface.
The cells flatten and the organelles
disintegrate.
Eventually the living cells of the
inner epidermis become the dead,
tough, waterproof, and flexible
outer layer.

7. Epidermis As the living cells replicate they produce
keratin and melanin.
Keratin
tough fibrous protein
for strength and a waterproof texture.
Melanin
dark brown pigment
accounts for the variations in skin color.

8. Dermis Epidermis blood vessels nerve endings glands sense organs
smooth muscles
hair follicles.

9. Dermis
Skin Cross Section

10. Subcutaneous tissue
Layer of fat
Insulation
Food reserve

11. Glands of the Dermis Two major types Sweat glands Sebaceous glands
Eccrine- thin and watery
Apocrine- thick, kicks in at puberty
Sebaceous glands
Sebum- an oil that coats the surface of the skin
flexibility and waterproofing
Hair Follicle

12. Finger and Toe
Nails
Nails grow rapidly from the nail root.
During cell division the nail root fills with keratin
producing a plate-like nail.
Fingernails grow 4 times
faster than toe nails with
an average rate of 3 millimeters
per month.

13. What to Know
Functions of Integumentary system.
The layers of the skin.
Various components of the epidermis and dermis, including the nails.