Integumentary system

epidermis

mostly epithelial cells (stratified squamous), avascular(no blood vessels)

dermis

mostly dense irregular connective tissue, vascularized (has blood vessels)

subcutaneous layer

no part of the skin (hypodermis)

integumentary system

is the skin plus accessory structures, the hair, certain glands, and nails

stratum basale

can be called stratum germinativum, keratinocytes and melanocytes; mitotic layer adjacent to basement membrane, bottom layer before dermis

stratum spinosum

8-10 layers, some mitosis, makes keratin precursor; dendritic cells most abundant here

stratum granulosum

2-3 layers, keratinization begins here

stratum lucidum

only palms and soles, (clear layer); only found in thick skin

stratum corneum

20-30 layers of dead cell, shed regularly (flakes); shells filled with keratin, make barrier

basement membrane

between epidermis and dermis, hold them together; composed of basal and reticular lamina

basal lamina

top layer of basement membrane, glycoproteins + collagen fibers

reticular lamina

Extracellular material containing collagen fibers

papillary dermis

areolar connective tissue, free nerve endings, dermal ridges, friction ridges, fingerprints

reticular dermis

deep and thick, 80% of dermis, tears in it become stretch marks

melanin

yellow, brown, or black pigments; protection from UV light (equator), people have about the same # of melanocytes but darker ppl just produce more melanin

mole

concentrated melanin

vitiligo

patches of uneven melanin production

carotene

yellow-orange pigment; hides it but less melanin exposes more yellow

Hemoglobin

pinkish, not in skin but in RBCs which shows through epidermis;

blushing

due to increased blood flow under the skin

blanching

due to decrease in blood flow to skin (pale)

follicle

goes into dermis, surrounds root

arrestor pili

smooth muscle associated with hair follicle, causes goosebumps, associated with fright

eponychium

cuticle

hyponychium

below the free edge of the nail

nails

thin plate with layers of dead stratum corneum cells with hard keratin on nailbed, a part of epidermis

sebaceous glands

oil gland, all over the body expect palms and soles, lubricate and waterproof hair and skin, inhibits growth of bacteria

blocked gland

blackhead

infected gland

pimple, pustule

vernix caseosa

cheesy covering at birth, produced by sebaceous glands-- waterproofs skin in amniotic fluid

sudoriferous glands

sweat glands, in dermis and subcutaneous tissue, found everywhere except nipples and parts of genitals

aprocrine sweat glands

associated with hair follicles, found in axillary and genitals areas- becomes active at puberty; organic materials released and bacteria decomposes resulting in odor

eccrine sweat glands

found everywhere!, secrete substance 99% water, sweating prevents body from overheating (role in temp regulation)

metabolism

source of heat production

skin

source of heat loss

hypothalamus

regulates body temperature, creates homeostasis

first degree burn

epidermis only

second degree

epidermis and upper dermis

third degree

Epidermis, dermis and subcutaneous tissue (full thickness), painless because sensory receptors destroyed

rule of nines

Head and neck 9%, upper extremities 18% each, lower extremities 36% each, trunk 36%, perineal area 1%