The skin has three layers: the hypodermis, dermis, and epidermis. The hypodermis is beneath the skin and contains adipose tissue. The dermis has two layers - a reticular layer made of collagen and elastin that gives the skin strength and elasticity, and a papillary layer containing blood vessels. The epidermis has multiple layers called strata, with the bottom stratum basale containing cells that divide and push new cells outward, and the top stratum corneum made of dead keratinized cells that form a protective barrier.

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