Integument System Flashcards
2 layers of the skin
epidermis & dermis
functions of integumentary system
- sensory
- thermoregulation
- metabolism
- sexual signaling
cells of the epidermis
keratinocytes
malanocytes
langerhans cells
merkel cells
karatinocytes
- most abundant cell of epidermis
- produce keratin
- form epidermal water barrier
- produce vitamin D
skin is categorized as ____ or ____
thick or thin
thick skin
- found on palms of hands and soles of feet
- 5 layers to epidermis
- subject to most abrasion, hairless
thin skin
- found everywhere except palms of hands & soles of feet
- 4 layers to epidermis
- most areas contain hair follicles
layers of epidermis
- stratum basale (stratum germinativum
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
stratum basale (germinativum)
- single layer of mitotically active cells, rests on basement membrane, allows epidermal renewal of keratinocytes
- keratinocytes undergo keratinization, then apoptosis
stratum spinosum
thickest layer, synthesize keratin
stratum granulosum
- most superficial layer of still intact nucleated cells
- keratinocytes contain keratohyalin granules (contain keratin)
stratum lucidum
- found only in thick skin
- layer of flattened keratinocytes
- cytoplasm contains packed keratin filaments
stratum corneum
- anucleate squamous cells (keratinocytes) filled with keratin filament
- extra lipid cell layer as water barrier
- continuously shed and replenished
melanocytes produce and secrete ____
melanin
melanin
protects against mutagenic affects of UV radiation
melanin accumulates in vessels called ____
melanosomes
langerhans cells
- dendritic APCs, derived from monocytes
- present antigens to T lymphocytes in nearby lymph nodes
- mostly in stratum spinosum
merkel cells
- associated with nerve ending & function as receptors for light touch and texture (tactile sensation)
- abundant in highly sensitive skin (finger tips, bases of hair follicles)
surface of dermis has many projections called ____
dermal papillae
dermal papillae
fingerlike projections of loose CT into undersurface of epidermis
sublayers of dermis
- papillary layer
- reticular layer
sensory receptors of the skin
- meissner’s corpuscles
- pacinian corpuscles
function of meissner’s corpuscles
fine, light touch receptors
structure of meissner’s corpuscles
- encapsulated nerve ending
- unmyelinated sensory nerve fibers follow a spiral path
- Schwann cells surrounding in helical matter, forming several lamellae
location of meissner’s corpuscles
- dermal papillae
- most numerous in fingertips, palms, soles
function of pacinian corpuscles
receptors for course touch, pressure, vibration
location of pacinian corpuscles
deeper dermis and hypodermis, especially in fingertips
structure of pacinian corpuscles
concentric lamellae of schwann cells surround unmyelinated afferent nerve fiber
what are hairs?
elongated keratinized structures that form within hair follicles
hair bulb
terminal dilation of hair follicle
base of hair bulb is invaginated by a well vascularized tuft of loose CT ____
dermal papillae (sustain the hair follicle)
hair root
portion of hair within skin
structure of hair root
- inner medulla (less keratinized)
- cortex (heavily keratinized)
- thin outer cuticle (v heavily keratinized)
hair follicle has an outer ____ and an inner ____
CT root sheath
epithelial root sheath
hair shaft
external portion of hair that extends above epidermis
sebaceous glands secrete ____ via ____ secretion
sebum
holocrine
sebum
- oily lipid substance that coats the hair and skin surface
- cells fill with small fat droplets filled with sebum
holocrine secretion
cells accumulate product as they mature and enlarge, ending in rupture of cells and release of product
arrector pili muscle
- small bundle of smooth muscle attaches to hair follicle
- contraction twists hair follicle and elevates hair, forming goosebumps
- helps deliver sebum from sebaceous gland into hair follicle
pilosebaceous unit
- hair follicle + hair
- arrector pili muscle
- sebaceous gland
2 types of sweat glands
eccrine and apocrine
function of eccrine sweat glands
produce sweat that is mostly water onto skin surface where evaporation cools the body
eccrine sweat glands
_____ cells surround basal aspect of secretory segment
myoepithelial cells
function of contraction of myoepithelial cells of eccrine sweat glands
helps release sweat from gland into ducts
eccrine sweat glands function via ____ secretion
merocrine
apocrine sweat glands contain…
slightly viscous, protein rich products (may develop odor due to bacterial activity)
