Anatomy U2Q1

functions of the integumentary system

1. protection

mechanical, chemical, bacterial, uv radiation, thermal damage, dessication

2. heat loss + heat retention

3. excrete urea + uric acid in perspiration

4. synthesize vitamin D

skin structure

what are the 3 skin levels?

Epidermis

the thin, tough, outermost layer of the skin. it is “avascular” (lacks blood vessels/no blood supply).

stratum layers: CLGSB (can large geese shake beaks?)

1. stratum-basale: closest to dermis, actively dividing cells, deepest layer

2. stratum spinosum: thick layer that provides strength, holds cells together

3. stratum granulosum: thin layer of keratinocytes that prevent water loss

4. stratum lucidum: thin layer of translucent dead skin cells found on thick skin areas (heels)

5. stratum corneum: outermost layer (20 cells, 3/4th of epidermis) made of cornifield dead cells. completely filled with keratin

what is dandruff?

dead skin cells of stratum corneum sloughing off

what is melanin?

natural pigment produced by melanocytes in stratum basale.

effects of the sun

• skin becomes leathery

• immune system becomes depressed

• may trigger herpes simplex outbreak

• dna of skin cells becomes altered leading

dermis

your hide, blood vessels play a major role in temperature regulation.

1. papillary layer

contains dermal papilae (indent epidermis). dermal loops furnish blood to epidermis. touch receptors and free nerve endings. whorls on hands/feet. hands have unique-sweat gland finger tips

2. reticular layer

sweat glands, oil glands, pressure receptors (lamellar corpuscles), phagocytes (keep bacteria from getting in), collagen (bind water-hydrate, dermis toughness)

cyanosis

hemoglobin is poorly oxygenated; blood/skin appear blue. common in breathing disorders/heart failure

when will skin be red?

embarrassment, fever, hypertension, inflamation, allergies

when will skin be pale/blanched?

fear, anger, anemia, low blood pressure, impaired blood flow

when will skin be yellow?

liver disorder-bile absorbed in blood and deposited in tissue (jaundice)

when will skin be blackish-blue?

blood escapes circulation and clotted in tissue spaces-due to hematoma. vitamin c deficiency or hemophilia increase bruising tendencies

tinea pedis

fungal infection causing peeling skin, itchy, red skin between toes

boils and carbuncles

inflammation of hair follicle or sebaceous oil gland. boils are the shape, carbuncles are the infection (typically staph)

cold sores

small, fluid filled blisters that itch and sting from herpes virus. virus lays dormant in cutaneous nerve until triggered by stress, sun, or fever.

contact dermitis

itchy, red, blisters on skin because of contact with chemicals like poison icy

impetigo

raised, fluid-filled blisters caused by staph infection. typically yellow crusted/seen in elementary children

psoriasis

chronic condition, overproduction of skin cells, auto-immune disorder, dry silver scales that itch, burn, and crack

lanugo

hairy cloak around fetus of 5-6 months (shed before birth normally)

vernix caseosa

white, cheesy covering of baby when born. produced by sebaceous glands to protect baby while in uterus

what happens to skin as we get older?

• lose subcutaneous color

• drier skin; itchier—less sebaceous oil

• thinning skin bruises, scratches easier

• bags under eyes, jowels sag/lose elastin/collagen

hair loss as we age

• by age 50; 1/3 of hair follicles have gone/thinned

• alopecia/baldness may result (hair there just colorless/thin)

• hair grays because melanin is impacted (gene produces it is delayed)

membranes of integumentary system

cutaneous: body's largest organ and primary outer protective boundary. it consists of a superficial layer of epithelial tissue

mucous: a soft-tissue barrier that lines internal cavities, organs, and tracts open to the outside environment

serous: thin, double-layered tissues that line closed body cavities and cover the internal organs inside them, (heart, lungs, abdominal organs)

synovial: thin, specialized layer of connective tissue that lines the inner surface of joints (knee)