[UNFINISHED] ANAT Lecture 4 - INTEGUMENTARY

Slides 3-4 resume at slide 4

brief functions of integumentary system

protection

sensation

thermoregulation

vitamin D synthesis

function of integumentary system: protection

outer layers protect against physical and chemical threats (UV, corrosive chem)

acts as waterproof barrier to keep water in

sweat glands produce many antimicrobial compounds (dermcidin)

function of integumentary system: sensation

many types specialized sensory structures

most densely-packed in fingertips

diff: pain, temp, pressure, touch

function of integumentary system: thermoregulation

keep heat in or lose through radiation and convection

function of integumentary system: vitamin D synthesis

UV radiation absorbed by skin, triggering synthesis of various forms of vitD

essential for absorption of calcium and phosphorous

crucial to formation of many types WBCs

rickets

mis shapen bones in children due lack of calcium resulting from insufficient vitD

3 main layers of skin

epidermis + dermis = true skin

under that is hypodermis aka subcutaneous tissue aka superficial fascia

thick skin has

5 epidermal layers

only palms hands and soles of feet

thin skin has

4 epidermal layers

everywhere else in body

layers of the epidermis from superficial to deep

stratum corneum

lucidum (not in thin skin)

granulosum

spinosum

basale

key to learning layers: follow the keratinocytes

cells that produce keratin - intracellular fibrous proteins that give structures hardness and water resistance

change in keratinocytes = change in layer