Transcript Integumentary System Notes Part 1

NOTES – INTEGUMENTARY SYSTEM PART 1
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.
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about the skin
Integumentary
System
SKIN
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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
• SKIN
• has 2 layers: DERMIS &
EPIDERMIS
• 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
2. PAPILLARY LAYER
• contains blood vessels – supplies
epidermis with blood
• this layer forms finger prints and
foot prints
• 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
• Next 2 Layers
• Stratum Spinosum
• Stratum granulosum (cells begin
to flatten in this layer)
• 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
• Dandruff Example:
• Callus & Corns Examples:
• calluses are generally on
the soles of the feet
• corns are between the toes or
on the outside of the toes
• 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
• ALBINO – no melanin at all