notes – integumentary system part 1. in 1 square inch of skin there are 4 yards of nerve fibers,...

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