Chapter 5 Flashcards
what does integumentary system do?
separates/protects from external environment.
-sensation, temp reg, Vitamin D, excretion of small amount of waste products
Epidermis is what epithelium
stratified squamous epithelium, divided into 5 strata (regions)
stratum basale
keratinocytes (product cells of superficial strata)
stratum spinosum
several layers of cells held together by desmosomes
stratum granulosum
cells filled with granules of keratohyalin.
cell death occurs.
stratum lucidum
layer of dead, transparent cells
stratum corneum
consists of many layers of dead squamous cells. most superficial cells slough off.
keratinization
transformation of living cells of stratum basale into dead squamous cells of stratum corneum
- keratinized cells have protective barrier - structural strength. cells not shed.
thick skin
has all 5 epithelial strata
thin skin
contains less layers per stratum. hair is only found here. stratum lucid is usually absent.
melanocytes
produce melanin inside melanosomes and transfer melanin to keratinocytes. size/distribution of melanosomes determine skin color. genetic but influenced by UV and hormones.
carotene
ingested plant pigment, causes skin to be yellowish
red skin color
-increased blood flow
cyanosis
- decreased blood flow / decreased oxygen
-pale/ blue skin
dermis
connective tissue, 2 layers: papillary and reticular
papillary layer
layer of dermis.
-projections called dermal papillae, composed of loose connective tissue and capillaries
reticular layer
-main layer of dermis
-dense irregular connective tissue consisting mostly of collagen
subcutaneous tissue
located beneath dermis. loose connective tissue that contains collagen/elastic fibers
- attaches the skin to underlying structures.
-site of lipid storage
lanugo
fetal hair
-replaced near time of birth with terminal hairs and velds hairs
hair 3 parts
shaft, root, hair bulb
root/shaft of hair
-composed of dead keratinized epithelial cells. -cortex cells containing hard keratin surround medulla of soft keratin.
-cortex is covered by cuticle (single layer of hard keratin)
hair bulb produces
hair in cycles (growth and resting stage)
hair color determined by
amount and kind of melanin present
arrector pili muscles
smooth muscle contraction causes hair to “stand on end” and produces “goose bumps”
sebaceous glands
produce sebum - oils hair and surface of skin
eccrine sweat glands
produce sweat (cools body)
apocrine sweat glands
produce organic secretion that gets broken down by bacteria - body odor
ceruminous glands
ear wax
mammary glands
produce milk
nail root / nail body
nail root is covered by skin
nail body is visible
nail matrix
forms almost all of nail. nail bed contributes
-lanula (white on thumb)
nail material
stratum corneum containing hard keratin
skin protects against
abrasion, UV, microorganisms, reg body temp, prevents water loss
hair protects against
abrasion, UV, heat insulator
nails protect
ends of digits
skin contains sensory receptors
pain, touch, hot, cold, pressure…allow proper responses to enviro
skin controls heat loss by
dilation/ constriction of blood vessels.
-sweat glands produce sweat, evaporates and lowers body temp
Skin exposed to UV
produces cholecalciferol - modified in liver and kidneys to produce vitamin D
-vitamin D increases blood calcium from small intestine
skin glands remove…
small amounts of waste products (urea, uric acid, ammonia) but not important amounts
partial-thickness burns
damage only epidermis (1st)
epidermis & dermis (2nd)
full thickness burns
3rd*. destroy epidermis, dermis and underlying tissue. skin graft usually necessary.
as body ages..
blood flow to skin declines, skin becomes thinner and elasticity is lost
-sebaceous and sweat glands become less active, # of melanocytes decreases (gray hair)
