skin Flashcards
skin system name
integumentary system. largest organ in body
cutaneous membrane
epidermis and dermis
epidermis
superficial epithelium
dermis
connective tissue
secondary structures
hair, nails, and variety of glands
hypodermis / subcutaneous
loose connective tissue below dermis
functions of the integument
protection, temp maintenance, synthesis and storage of nutrients, sensory reception, excretion (salt, water, and organic waste) and secretion (milk)
thick skin
(epidermis only) - palms and soles of feet, 5 layers (paper towel)
thin skin
(epidermis) - rest of body, 4 layers (lunch bag)
keratin
durable and water resistant / coats surface is skin / found in hair, calluses, nails / (in other animals, makes hooves, nails, horns)
layers of epidermis
stratum corneum stratum lucidum stratum grandulosum stratum spinosum stratum germinativum/basale basement membrane
stratum corneum
most superficial, 15-30 layers of flattened dead cells (deprived of O2 and nutrients), full of nutrients, 2-4 weeks to get here
stratum lucidum
clear, flattened and densely packed, full of keratin, living
stratum granulosum
these cells have stopped dividing and have started to produce keratin
stratum spinosum
these cells may continue cell division to add thickness to the epithelium
stratum basale
attached to basement membrane , contains stem cells that constantly divide , has ridge to increase surface area (no blood vessels in epidermis)
ridges in sb-
make fingerprints - unique to individual, genetically determined, only on palms and soles of feet
medicine through skin?
once drug gets through sc it’s easily absorbed
layers of dermis
papillary and reticular
hair follicles and sweat glands here too
papillary layer
loose CT, nerves and blood supply
reticular layer
dense and irregular CT with elastin and collagen fibers
hypodermis/subcutaneous layer
lots “O” fat , reduces heat loss, no vital organs
hair
found on almost all external surfaces, dead
not sure if have to know: lose 50 a day, head has 500,000 hairs, grow .3 mm a day, each hair lasts 2-5 years
hair follicles
where hair is produced
curly vs straight
straight - even growth, round crossection
curly - uneven growth, flat cross section
humidity and hair
when humid it absorbs water in air and becomes frizzy
dryness causes it to lose water and become brittle and break
hair color
produced by melanocytes, hormonal and environmental factors take a role, lightens naturally with age, gray is no pigment with air bubbles
hair papilla
provides nerves and blood supply
hair root
anchors hair to skim
hair shaft
part we see
cuticle
outer layer of hair made of overlapping cells
cortex
under cuticle
medulla
core of hair
arrector pili
muscle that makes hair stand on end and goose bumps
sebaceous glands
oil glands (holocrine), discharges oil or sebum onto hair which inhibits growth of bacteria and is natural conditioner
zits
sebaceous gland gets plugged and sebum builds up, bacteria grows and inflammatory response,
whitehead is enclosed under layer of skin
blackhead makes it to surface and breaks
sweat glands
apocrine - groin, pits, and head : odor / merocrine - palms, feet, and everywhere else : 99% water the rest is salt
skin repair
1) bleeding
2) inflammatory response
3) scab
4) stratum basale migrates to base of wound
5) new cells grow, collagen is produced, scab is lifted
aging and skin
lot of shit that mostly self explanatory
skin color
blood supply and number or type of pigment cells
carotene
yellow orange, carrots, gets converted to vit A used to maintain epithelial tissue
melanocytes
contain pigment, found in stratum germinativum
sun tan
sun increases melanocyte activity to protect deep layers and DNA from uv
overexposure to sun
destroys connective tissue, premature wrinkles, sun burn, skin cancer
sun poisoning
reaction of skin to uv rays, also called photodermatitis, swelling, burning, rash, peeling
xeroderma pigmentosum
genetic disorder - extreme sensitivity to uv rays - can’t go outside in daylight without special protection, skin and eyes can be severely damaged leading to cancer
freckles
small pigmented spots of extra melanin on pale face
birth marks
formed before brith, unknown origin
albinism
melanocytes exist but they don’t produce melanin
basal cell carcinoma
stratum germinativum- non life threatening
squamous cell carcinoma
stratum corneum - non life threatening
melanoma
melanocytes - extremely dangerous, often appear as moles
circulation and color
oxygenated blood - bright red
deoxygenated blood - maroon
embarrassed - blood vessels dialate
scared - vessels constrict
cyanosis
low O2 - dark red color - appears blue
