notes – integumentary system part 1. in 1 square inch of skin there are 4 yards of nerve fibers,...
TRANSCRIPT
NOTES – INTEGUMENTARY SYSTEM PART 1
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
Integumentary System
SKIN
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Quick Brainstorm
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)
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
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