CH 3 Flashcards
skin structure disorders and diseases (47 cards)
what is the integumentary system
organ system - skin, hair nails and exocrine glands
where is skin the thinnest and thickest
thinnest - under eyes, around eyelids
thickest- plasma of hands and soles of feet
what are appendages of skin
hair, nails, sweat/oil glands
how is a callus formed
repeated pressure causing to thicken.
what are the three layers the skin is composed of
epidermis, dermis subcutaneous tissue (hypodermis)
what is the epidermis and its 5 layers
outermost/thinnest. doesn’t contain blood vessels. reliant on dermis for nutrition for cell renewal . 5 layers start with stratum (latin for later)
top layer to deepest layer:
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum germinativum
5 layers of epidermis
stratum corneum- (horny layer) first line of defense (UV rays, pollution, allergens, viruses, bacteria, topicals) can access skin type, skin conditions ect. from this layer) scalelike cells constantly being replaced with cells full of keratin ( fiberous protein)
stratum lucidum-clear transparent under skins surface. small oval shaped cells (light can pass thru) most abundant in palms and soles of feet) gives traction so we don’t slip. fingerprints are dependent upon lucidum layer.
stratum granulosum- (grainy layer) cells look like small granules. dying cells pushed to surface and will replace dead skin cells as they shed. process of keratization complete with this layer
stratum spinosum-(spiny layer) layer just alive basal later (deepest layer) as cells rise to surface, form cogs/spot welds between cells. this is where langerhans (immune support cells) live. these cells protect body from infection by identifying harmful substances (antigens)
stratum germinativum- (basal layer) deepest layer. produces new epidermal skin cells thru mitosis to replace kerinized skin cells that are shed by daily cleansing / metabolism.column shaped cells produce cells called melanocytes. those cells produce melanosomes containing melanin
what is keratinization
chemical conversion of living cells to dead cells. skin renewal process takes 25-28 days. keratinized cells combine with fats, minerals, salts, water. makes up outer layer of skin (barrier function. protective and water resistant
what are the 2 types of melanin
pheomelanin and eumelanin
pheomelanin-red to yellow in color (light skin)
eumelanin- deep brown to black (dark skin)
what is the dermis
(true skin) underlying/ inner layer of skin. highly sensitive. 25x thicker than epidermis.
what are the 2 Layers that the dermis is made of
Papillary layer and reticular layer
papillary- upper layer located directly beneath epidermis. where u will find dermal papillae (small cone shaped containing large amounts of gel) this layer accounts for 10-20% of dermis
reticular- deepest layer of dermis. supplies skin with all its oxygen and nutrients. (home to: sweat glands, blood vessels, hair follicles, lymph vessels, arrestor pili muscles, oil glands, nerve endings. collagen fibroblasts, elastin)
what is the subcutaneous layer
fatty layer below dermis, varies in thickness.gives smoothness/ contours body. acts as emergency source of food for use as energy, serves as cushion for skin
what surface endings of the skin are nerve fibers covered with
motor nerve fibers- cause goosebumps
sensory nerve fibers- react to head/cold/touch/pressure/pain. send messages to brain
secretory nerve fibers-distributed to sweat and oil glands of skin.control flow of sebum to surface of skin
what layer of the dermis houses nerve endings with sense of touch
papillary layer. registered basic sensations (touch, pain, heat, cold pressure) most abundant in fingertips (needed most)
what 2 structures does skin get its flexibility, strength, and form from
collagen and elastin. both consist of flexible protein fibers in dermis. (make up 70% of dermis)
collagen- gives skin form and strength. 16 types. type 1 and 3 are most abundant in skin. interwoven with elastin
elastin- makes up 15% of collagen fibers. gives skin flexability.
what are the 2 duct glands that extract materials from blood to form new substances
sudoriferous glands (sweat glands) and sebaceous glands (oil glands)
sudiriferous gland (sweat gland)
excrete sweat from skin. most numerous on palms, soles of feet, forehead, genitals and armpits
what are the 2 types of sweat glands in bodies
apocrine and eccrine
apocrine- hair follicles, scalp, underarms, genitals. fatty sweat. when we are emotional, stress can stimulate apocrine glands. combines skin bacteria creates odorous fatty acid
eccrine- major sweat glands of body found all over skin. excrete to surface of skin. regulates body temp, eliminate waste from body
what is wicking
evaporation of sweat cools skin surface. increased by exercise , heat emotions and drugs. controlled by nervous system
what is sebum
semi fluid. triglycerides and fatty acids make up 57.5% sebum. ester waxes=26% of sebum. squaline=12%. cholesterol=least abundant lipid in sebum. glands secrete sebum to lubricate skin and preserve softness of hair. these are found in all parts of body EXCEPT palms of hands and soles of feet. larger and more abundant on face and scalp.
what are sebaceous glands responsible for
determining skin types (oily, dry, combo, normal.)
what happens to sebum with healthy skin vs bad skin
healthy- sebum flows thru oil dicts to opening at top of hair follicles. mixes with sweat and forms acid mantle/barrier function
bad- sebum hardens and ducts get clogged from pollution/bad hygiene. pore impaction/comedo can occur. could lead to acne papule or pustule.
what is acne
skin disorder chronic inflammation of sebaceous gland from hardened secretions, bacteria and gaseous sacs.
what does lymph do
bathes the skins cells and removes toxins. clear fluid supplied from lymph nodes
