1. Integumentary System

2. Integumentary System Made up of skin, hair, and nails
Acts as primary defense of immune system
Helps body maintain healthy internal environment

3. Integumentary System Skin Largest organ in the human body!
Protects by keeping moisture in and foreign particles out of body
Nerve endings throughout your skin allow you to feel what’s around you and react
Helps regulate body temperature (homeostasis)
Helps rid waste –
2 major layers thick
Epidermis and Dermis

4. Integumentary System Epidermis
Composed of Epithelial tissue
Most epidermal cells are dead and filled with proteins called Keratin
Keratin is a protein that allows cells to be durable and tough

5. Skin Layers Epidermis Stratum Corneum (horny) Stratum Lucidum (clear)
Stratum Granulosum (granular)
Stratum Spinosum (spiny)
Stratum Basale (basal)

6. Integumentary System Dermis
Lies underneath epidermis
Mostly connective tissue
Contains fibers made of collagen
These fibers provide strength to the tissue and allow skin to bend and twist without tearing

8. Integumentary System Dermis
Layers of the Dermis
Papillary layer – Fingerlike projections – loose connective tissue
Reticular layer – irregular connective tissue – dense connective tissue

10. Integumentary System Skin Color
Determined by darkening chemical in skin called melanin
Increase in melanin = darker skin color
Decrease in melanin = lighter skin color

11. Integumentary System Skin Color
Melanin is found in upper layer of epidermis of skin
Absorbs much of harmful radiation from sun to decrease DNA damage that can lead to cancers.

12. Integumentary System Hair
Formed at bottom of tiny sac called hair follicle
Hair grows as new cells are created in hair follicle
Old cells get pushed upward

13. Integumentary System Hair
The only living cells in a hair are in the hair folicle
Hair protects skin from UV Radiation and helps keep particles out of body
Eyelashes, nose/ear hair, pubic hair, armpit hair etc…
Color comes from melanin – like skin color

14. Integumentary System Hair
Hair regulates body temperature by contraction of tiny muscles attached to the hair follicle.
When these muscles contract they cause the follicle to push upward toward the epidermis and create “goose bumps”
If the follicle contains a hair the hair will stand up
This will cause the warm air to be trapped between the hair and the body and thus keeping the body warmer – Acts like a sweater

15. Integumentary System Nail
Protect tips of fingers and toes so as to remain soft and sensitive yet tough
Form from nail roots under skin at base and sides of nails
As new cells form, nail grows outward

16. Integumentary System Nail Parts
Free edge
Body
Root
Lunula
Nail folds
Eponychium
Cuticle
Nail bed
Nail matrix

17. Integumentary System Sweat glands
Sudoriferous – Dermis layer
Small organs in the skin that produce sweat
Salty liquid that flows to surface of skin
As sweat evaoorates, skin is cooled
Aid in removing several types of waste chemicals from bloodstream

18. Integumentary System oil glands
Sebaceous glands – Dermis layer
Release oil that keeps hair flexible and helps keep epidermis waterproof/water resistant