NOTES – INTEGUMENTARY SYSTEM PART 1

1. NOTES – INTEGUMENTARY SYSTEM PART 1

2. SKIN FACTS In 1 square inch of skin there are 4 yards of nerve fibers, 1300 nerve cells, 100 sweat glands, 3 million cells, and 3 yards of blood vessels.

3. Brainstorm: Write and share with someone near you everything you know about the skin Quick Brainstorm Integumentary System SKIN

4. Notes – Integumentary System • HYPODERMIS • Location: • beneath the skin • consists mostly of loose connective and adipose tissue • half of the body’s stored fat is here

5. SKIN • has 2 layers: DERMIS & EPIDERMIS

6. DERMIS (2 layers) • division of layers is not distinct 1. RETICULAR LAYER • dense connective tissue What type of tissue is this? Stratified squamous epithelium • collagen & elastin makes the skin strong and elastic

7. 2. PAPILLARY LAYER • contains blood vessels – supplies epidermis with blood • this layer forms finger prints and foot prints

8. EPIDERMIS • made out of layers called STRATA (plural stratum) • Bottom Layer • Stratum Basale (aka: germinativum) • cell division here – new cells push up & out toward skin surface

9. Next 2 Layers • Stratum Spinosum • Stratum granulosum (cells begin to flatten in this layer)

10. Top Layer • Stratum Corneum • dead, KERATINIZED cells • Keratinization: cells die and change chemically to form a protective barrier • can be 25 or more layers • this layer is associated with dandruff, calluses, corns

11. Dandruff Example:

12. Callus & Corns Examples: • calluses are generally on the soles of the feet

13. corns are between the toes or on the outside of the toes

14. SKIN COLOR • produced by a skin pigment called MELANIN • MELANOCYTES • cells that produce melanin located in the stratum basale • melanin also produces freckles & moles • birthmarks are congenital disorder of capillaries in dermis

15. ALBINO – no melanin at all