1. NOTES – INTEGUMENTARY SYSTEM PART 1

2. 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. SKIN FACTS

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

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

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