integumentary system

skin

• body’s outer covering

• largest organ

  • composed of 3 layers

accessory organs

• hair follicles

• finger and toe nails

  • skin glands

functions of skin

• protection

• first line of defense against bacteria and viruses

  • protects underlying structures from UV radiation and dehydration

    • regulates body temperature

    • vitamin D protection

body too hot

• dermal blood vessels dilate

  • more blood sent to surface so heat escapes

body too cold

• dermal blood vessels constrict

  • prevents heat from escaping

sensation

has nerve receptors that detect heat, cold, and pain

excretion

perspiration aids in cooling, results in loss of water and minerals

epidermis

• outermost layer of skin

• epithelial tissue

• no blood vessels

• no bleeding if scraped

• has keratin

  • has melanocytes

rubor or erythema

flushing of the skin when blushing due to dilated blood vessels

pallor or pale

anxiety and cold can cause blood vessels to constrict

cyanosis

bluish tint to the skin when it’s not getting enough blood

dermis

• thick layer, contains blood vessels, arteries, veins, capillaries, and nerves

• contains sweat glands, hair follicles

• dermal punctures and finger pricks here

subcutaneous layer

• connective tissue

• composed of adipose tissue (fatty layer) and larger blood vessels

  • subcutaneous injection site (slower release of medication)