Ch.7 Skin Structure

Dermatology

Medical branch of science. study of skin

12 years post high-school education

Skin

largest organ of body

average weighs 6-9 pounds for adults

surface slightly acidic

Callus

thickened part of skin due to constant pressure

scalp skin

larger and deeper hair follicles

epidermis

outermost, thinnest layer.

5 layers

stratum cornium

layer seen and treated

stratum lucidum

transparent layer, melanin is visible, cells are almost dead

stratum granulosum

grainy layer

stratum spinosum

layer where shedding of skin first begins

stratum germinative / Basel cell layer

deepest layer, melanin is produced, melanocytes

dermis

underlying or inner layer, derma corium, true skin. 25 times thicker than epidermis

papillary layer

outermost layer of dermis

houses nerve endings that provide body with sense of touch

keratin

fibrous protein, principal component of hair and nails

Dermal Papillae

small, cone shaped elevations, bottom of hair follicles

Epidermal-dermal junction

top of papillary layer where joins epidermis

Reticular layer

deeper layer of dermis, supplies oxygen and nutrients to skin

Subcutaneous layer

fatty tissue found below dermis

motor nerve

carry impulses from brain to muscles

sensory nerve fibers

send messages to brain

Melanin

tiny grains of pigment deposited in cells. skin color

pheomelanin

red/yellow

eumelanin

brown/black

Collagen

fibrous protein, gives skin form and strength

elastin

fibrous protein gives skin flexibility, helps regain shape after expanded

sebaceous glands

oil-glands connected to hair follicles

comedo

hardened sebum, sebaceous duct becomes clogged

papule

small-round elevation on skin contains fluid, may develop pus

water

nutrient of body, makes up 50-70% of body’s weight

Vitamin A

improves the skin’s elasticity and thickness

Vitamin C

promotes production of collagen

Vitamin D

enables body to properly absorb and use calcium