anatomy lecture- exam 1 (ch.4) Flashcards
- most visible & largest organ system
- synthesize D3
- thermoregulation
- excretes some waste products
- sense stimuli: temp, pressure, touch & pain
skin
integumentary system is composed of:
- skin
- hair
- nails
- sweat glands
- sebaceous glands
- mammary glands
- epidermis
- dermis (papillary layer & reticular layer)
cutaneous membrane
- nourishes & supports epidermis
- forms dermal papillae
- loose connective tissue + capillaries + neuron axons
- attches to epidermis
papillary layer (dermis)
- attaches skin to deeper tissues
- sensory receptors
- blood vessels assist in thermoregulation
- dense irregular connective tissue proper
- hair follicles, sweat glands, sebaceous glands
reticular layer (dermis)
- protects dermis from trauma & chemicals
- controls permeability & prevents water loss
- synthesizes vitamin D3
epidermis
- keratinocytes
- malanocytes
- merkel cells
- langerhans cells
cellular composition of epidermis
- most common cell
- produce keratin, die, become outer layer
keratinocytes
- pigment cells
- produce melanin (determines skin color according to genes)
melanocytes
- sensory cells ; touch
merkel cells
- wandering macrophages
-patrol for pathogens & engulf them
langerhans cells
found on palms of hands and soles of feet
- offers extra protection w/ special stratum lucidum
thick skin
found everywhere in the body
thin skin
- deepest layer, attachment to basal lamina
- basal (stem cells), merkel cells, melanocytes
- single layer of cells
stratum basale
- keratinocytes, melanocytes, Langerhans
- multiple layers of cells
- becomes flatter & thinner as you go up
stratum spinosum
- last layer where cells have nuclei & is a living cell
- Keratinocytes start making keratin & keratohyalin
- callouses formation
stratum granulosum
appears as a glassy layer in THICK skin ONLY
- stacks of dead cells
- high amounts of keratin
- cells lack organelles & nuclei
stratum lucidum
outermost layer
- layers of flattened, dead keratinocytes maintained by glandular secretions (sebaceous & sweat glands)
stratum corneum
touch sensors
merkel cells
become keratinocytes
basal cells
trigger immune response
langerhans
unique wavy pattern formed by papillary layer that increases surface area and creates more structural integrity via points of attachment
epidermal ridges
skin color: thickness of stratum corneum; thick skin Is ___ in color
lighter
- blushing, overheating: red color hemoglobin
- pallor: anemia, drop in BP
- bruise: hematoma in skin
dermal blood supply
yellow-orange pigment from diet, can be converted into vitamin A
carotene
brown, yellow-brown, black pigment
- produced by melanocytes
- synthesized/ stored in melanosome
- moles: overgrowth of melanocytes
- albino: doesn’t produce melanin
- freckles: aggregations of melanin
melanin
- needed for vitamin D synthesis
- can damage cells
ultra violet (UV) radiation
provide tensile strength
collagen fibers
allow skin to stretch & recoil
elastic fibers
reticular fibers break due to pregnancy or weight gain
- skin doesn’t recoil, instead creases/ wrinkles
tension lines
- (subcutaneous) layer is deep to dermis
- helps stabilize integument
hypodermis
hypodermis consists of
adipose tissue (primary component) & major blood vessels
- hair follicles
- exocrine glands
- nails
- mammary glands
- ceruminous glands
accessory structures
- cutaneous plexus: main arteries & veins
- subpapillary plexus: smaller blood vessels
- blood flow regulated- thermoregulation & flow to other tissues of body
- lymph vessels
blood vessels
- controls blood flow to the skin
- adjusts gland secretion rates
- monitors sensory receptors
nerve fibers
- tactile corpuscles: light touch
- Ruffini corpuscles: stretch receptors
- lamellar corpuscles: deep pressure & vibration receptors
receptors for nerve fibers
hair follicles & hair are found everywhere except
- palms
- soles of feet
- sides of fingers & toes
-lips
nonliving, visible portion of hair
- medulla: soft keratin
- cortex: hard keratin
- cuticle: outer layer
hair shaft
portion of hair in follicle being formed; anchors hair
hair root
organs that form hair
hair follicle
nerve & blood supply; supports matrix
hair papilla
basal cells that divide to become hair
hair matrix
- protection from UV light
- insulation
- guards entrance to nose & ears
- when touched, hair sends signals via root hair plexus
- contraction of arrector pili muscles; goose bumps
functions of hair
- vellus
- terminal
- color
- shape
types of hair
hair that covers most of the body; lacks a medulla
vellus
hair that is found on the head, eyebrows & eyelashes
terminal
- more melanin: darker hair
- decreased production: gray hair
- white hair: lack of melanin in hair shaft
- influenced by: genetics / hormones / environmental factors
hair color
based on follicle shape
- straight: round follicle
- curly: flattened/ kidney bean follicle
hair shape
active stage (2-5 years)- hair grows 0.33 mm/daily
growth/ replacement of hair
- hair loses its attachment to follicle
- hair becomes a club hair
- male pattern baldness: changes in sex hormones
resting stage
sebaceous gland & sweat gland
glands in skin
apocrine glands & eccrine sweat glands
mechanism of sweat glands
ceruminous gland & mammary glands
special apocrine glands
- make sebum
-sebum: lipid mixture - secrete oily lipid (sebum) that coats the hair shaft & epidermis
- lubricate epidermis
- inhibit bacterial growth
- holocrine secretion
sebaceous glands
if ducts of sebaceous glands become blocked:
acne may occur & furuncles may develop
large sebaceous glands; no hair (shaft)
sebaceous follicles
make sweat
- sweat: aids in thermoregulation & water excretion of salts, N waste & some metabolites
- found all over the body
- high concentrations on palms & soles
- eccrine secretion
eccrine sweat glands
active at puberty
- high density in armpit & areola
- produce odorous secretion
- secretions can contain pheromones
- eccrine secretion
apocrine glands
- produce milk under control of hormones from pituitary gland
- apocrine secretion
mammary glands
- found only in ear canal
- produce cerumen in conjunction w/ sebaceous glands
- provide minimal physical protection to ear drum
ceruminous glands
- provides protection for distal-most phalanges
- made of keratin
nails
