integumentary system Flashcards
functions of the skin
protection, body temp regulation, cutaneous sensation, vitamin D synthesis, excretion of waste
characteristics of epithelial tissue
avascular + mitotic
epidermis cells are compromised of…
keratinized stratified squamous epithelium
keratinocytes
manufactures keratin
keratinocytes function
structural protein that toughens + wtaerproofs the skin surface
melanocytes
manufacture melanin
where are melanocytes found?
stratum basale
melanocytes function
gives skin color and adaptation to sun exposure
dendritic cells
provide immune function
what are the other names for dendritic cells?
histocytes or langerhans cells
merkel cells
tactile mechanoreceptors
what are the other names for merkel cells?
discs or tactile cells
stratum corneum
15-20 layers of flattened, keratinized dead cells
stratum lucidum
only in thick skin of hands and feet
stratum granulosum
flattened cells filling with keratin
stratum spinosum
synthesizes keratin and vitamin D/cholecalciferol
stratum basale
mitotic layer that contains melanocytes and merkel cells
what layer of the skin contains mitotic cells?
stratum basale/germinativum
which layer of the skin provides waterproofing?
stratum corneum
layers of the dermis
papillary layer + reticular layer
papillary layer
loose connective tissue with elastic fibers that create dermal ridges (fingerprints)
reticular layer
dense irregular connective tissue. distensible + resilient but overstretching causes tearing (stretch marks)
contents of the dermis
blood vessels, hair follicles, muscle fibers, exocrine glands, sensory receptors, + nerve fibers
subcutaneous tissue (hypodermis)
loose connective tissue + adipose tissue with blood vessels + nerve fibers
what does subcutaneous tissue connect?
skin to underlying deep fascia
adipose tissue function
insulation and energy reservoir
do men or women have a higher percentage of adipose tissue?
women
hair function
protection and identification of individuals within a species
hair follicle
tube like structure protruding down into dermis that houses an individual hair. includes connective tissue root sheath
hair bulb
zone of actively dividing cells at the base of the hair. contains melanocytes
hair root
column of flattened, dead keratinized cells within the follicle made up of medulla, cortex + cuticle
hair shaft
column of flattened, dead keratinized cells external to skins surface
arrector pilli muscles
attach hair follicle to papillary layer of dermis. contract in response to cold or activation of the sympathetic fight or flight response
nails function
protection/defense, facilitation of digital dexterity
nail plate
modified hardened stratum corneum
lunula
pale, half-moon shaped region at the proximal end of the nail plate, where underlying nail bed is the thickest
nail bed
underlying epidermis (stratum basale + stratum spinosum)
sebaceous glands function
lubricates + waterproofs hair and stratum corneum. attached to hair follicle
what type of secretion are sebaceous glands?
holocrine secretion
apocrine glands
sudoriferous (sweat) glands of axillary + pubic regions. smelly merocrine secretions
eccrine glands
sudoriferous (sweat) glands all over the body. not smelly merocrine secretion
eccrine glands function
regulate body temp + elimination of chemical waste from the body
apocrine glands function
mate attraction
body temp regulation when… body temp is high + air temp is lower:
blood vessels DILATE allowing more heat to leave the body
body temp regulation when… body temp is high + air temp is higher:
body produces sweat to cool itself down
body temp regulation when… body temp is too low
erector pili muscles contract to increase insulation
long term adaptation to life in hotter climates
blood vessels grow out to a more superficial layers to more effectively dissipate heat
long term adaptation to cold environments
retraction + constriction of superficial cutaneous blood vessels/extremities
what tactile receptors are located in the epidermis?
thermoreceptors, nociceptors, merkel cells/discs
what tactile receptors are located in the dermal papilla?
meissner’s corpuscle
what tactile receptors are located in the dermis?
hair endings, ruffini corpuscle, pacinian corpuscle
