Integumentary Flashcards
Functions of integument
protective covering
regulation of body heat
housing of sensory receptors
synthesis of vitamin D
excretion of waste through perspiration
epidermis
most superficial layer composed of keratinized stratified squamous epithelium
the four cell types in the epidermis
kartinocytes; makes keratin
melanocytes; makes melanin
(langerhans) dendritic cells; immune cells
merkel cells (discs); type 1 tactile mechanoreceptors
stratum basale
deepest layer highly mitotic
stratum spinosum
mitotic only in deepest layers; begins synth of keratin
stratum germinativum
stratum basale+stratum spinosum
stratum granulosum
flattened cells filling up with keratin
stratum lucidum
present only in thick skin
stratum corneum
20-30 layers of flattened keratinized dead cells
dermis
connective tissue, houses muscles fibers, blood vessels, hair follicles, exocrine glands, and nerve fibers
papillary layer
loose C.T. directly deep to epidermis
is ridged due to pulling of elastic fibers (fingerprints)
reticular layer
dense irregular C.T. just deep to papillary layer
stretchable and resilient; makes stretch marks
subcutaneous layer
adipose tissue and loose C.T. with blood vessels
binds skin to underlying organs
purpose of adipose in subcutaneous layer
heat insulator and energy resevoir
holds body heat steady or releases it
distribution of adipose varies through body and sexes (women with more)
thickness of layer can indicate nutrtion
pink skin color
blood flow in dermis and subcutaneous layer
yellow skin color
carotene; yellowish pigment through diet
an increased amount of keratin in stratum corneum-common in Eastern asia people
brown skin color
melanin in stratum basale-coloration varies on concentration of melanin
freckles
small patches of concentrated melanin
function of skin coloration
ages and sex differences
darker skin tones found in areas of high sunlight
lighter skin tones in areas of low sunlight
dark skin tones protect against …
damage from UVR
melanin absorbs UVR and prevents it from reaching mitotic cells in dermis and stratum germinativum
a thicker stratum cornuem prevents UVR from reaching mitotic cells
hair and the hair follicle
resides in the dermis and subcutaneous layer, but originates from the epidermis
hair present on nearly all skin surfaces
serves for protection and identification
follicle
tube-like; protrudes into dermis and houses one hair
bulb of hair
zone of active cells at base of hair
root of hair
column of flattened dead keratinized cells in follice
shaft of hair
column of flattened dead keratinized cells external to skin
the root and shaft are made up of a ….
medulla (inner core), cortex (middle section), and cuticle (outer portion)
goose bumps
arrector pilli is attached to follice surface and dermis
contraction of muscle causes hair to straighten in response to cold or sudden fear or threat situations
dark hair
high concentration of melanin
light brown hair
moderate amount of melanin
blond hair
little melanin
white hair
no melanin
gray hair
mix of unpigmented and pigmented hairs
red hair
pigment containing iron
texture of hair
depends on shape and size of follice
areas of dense hair concentraiton
the scalp, face, axilla, and pubic areas
men tend to have noticeable hair on back, chest, abdomen, chest, limbs, and face
Hairest and least hairest populations
europeans hairiest and East asians and amerindians are least hairy
nail plate
moded hardened stratum conreum
has nail root, body and free edge
nail bed
just deep to nail plate; continuous with stratum basale and spinosum of surrounding epidermis
lunula of nail
part of nail plate; half moon region at proximal end of nail plate
function of nails
protection and facilitation of dexterity
