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
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
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
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
