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 Brainstorm: Write and share with someone near you everything you know about the skin 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