Skin Part 3 Flashcards
sebaceous glands
alveolar, holocrine glands, consisting of branched acini
what is secreted in sebaceous glands?
entire cell
how many glands associated with each hair follicle in sebaceous glands?
one or more
how do sebaceous glands develop?
as outgrowths of external root sheath
what do sebaceous glands secrete? via?
oily sebum via pilosebaceous canal
what is sebum high in? (2)
lipid content and cell debris
what is sebum used for? (3)
waterproofing, moisturizing skin & hair
where are sebaceous glands also found?
non-haired transitional skin
where do sebaceous glands on non-haired transitional skin secrete?
secrete directly onto skin surface
Seborrhea is
excessive secretion of sebum
each hair follicle & associated arrector pili M & sebaceous gland =
pilosebaceous unit
Sweat glands
simple, coiled, tubular glands, surrounded by myoepithelial cells
sweat glands assist in
assist in secretion
2 types of sweat glands
merocrine/eccrine
apocrine
Merocrine (= eccrine)
sweat glands—by definition, secrete only product
where are merocrine glands in the human body?
In humans, distributed over most of body surface, except lips & genitalia
morphology of merocrine glands, what type of ducts?
Unbranched, coiled, tubular glands with 1-2 layers of cuboidal to columnar epithelium with excretory ducts
Secrete sweat onto skin surface via — —on epidermal ridge
sweat pore
Sweat contains a hypotonic solution of (4)
salts, ammonia, urea, uric acid
sweat glands are Important in thermoregulation for
evaporative cooling
Body loses average of ~600 ml/day due to evaporation from (3)
lungs, skin, & mucous membranes
thermoregulatory sweating is — (parasympathetic)
cholinergic
First occurs in (3) last on (2)
axillae, forehead, scalp
hands & feet
emotional sweating is — (sympathetic) & begins on (2)
adrenergic
palms & soles
Alternative explanation:
sweat glands innervated by sympathetic, but cholinergic Nn—Don’t use adrenaline (exception to rule)
apocrine sweat glands secrete
product along with some cytoplasm
apocrine sweat gland morphology
Coiled, tubular glands with large dilatedlumina
apocrine glands are located in (2)
axillae, groin
when do apocrine glands develop?
at puberty
type of apocrine cells
Secretory, cuboidal epithelium, 2-3 cell layers thick, surround large glandular lumen
Apocrine glands discharge thick, viscid secretions into
hair follicle
what do apocrine gland secretions contain (5)
Contain proteins, carbohydrates, ammonia, lipids, & organic products
Odorless when secreted, but bacterial breakdown results in
acrid odor
apocrine glands in mammals serves as
sexual attractant, pheromone
what are pheromones used in? (2)
scent marking, territoriality
Secretion in apocrine glands is —
adrenergic
Ceruminous (wax) glands in external auditory meatus (ear canal) are modified
apocrine glands
Secretion produced is
cerumen (ear wax)
Mammary glands develop along
paired epidermal ridges
paired epidermal ridges in mammary glands
mammary ridges or milk lines
mammary ridges or milk lines extend from
axillae to groin
In humans, only first pair of glands along — — develops
milk line
Highly modified apocrine sweat glands; identical in male & female until
puberty
In female, develop under influence of (2)
pituitary & ovarian hormones
following pregnancy, produce
milk to feed young
At menopause, cause (2)
atrophy & involute
Inactiveglands composed mainly of
dense, irregular, collagenous connective tissue, interspersed with adipose tissue & occasional smooth M.
Tubulo-acinar glands organized into
secretory lobules
mammary glands are drained by
terminal ducts
terminal ducts drain into larger — — which empty into — — in region of nipple
lactiferous ducts
lactiferous sinus
Pigmented region of epidermis surrounding nipple is
areola
areola cell type
stratified squamous epithelium with deep dermal ridges
mammary glands/areola contains numerous — —, including (2)
areolar glands
merocrine sweat & sebaceous glands
During lactation, mammary glands enlarge due to (2)
hypertrophy of secretory cells & accumulation of secretory product
First few days after birth, secrete
colostrum
colostrum
alkaline, yellowish secretion, with high protein & salt content, low lipid & carbohydrate
colostrum contains large amounts of
antibodies
antibodies are important in transfer of
passive immunity to offspring
Milk production is both
merocrine & apocrine
Protein sec is 1’ —;
lipid fraction is 1’ —
merocrine
apocrine
Meissner’s corpuscles
mechanoreceptors/ touch receptors in dermal ridges of papillary layer
Meissner’s corpuscles are especially prominent in (4)
hands, feet, lips, genitalia
Meissner’s corpuscles structure
Cylindrical structures ~ 150 um long
Afferent N fibers associated with minimally modified
Schwann cells
Pacinian corpuscles
mechanoreceptors located in dermis & hypodermis
Pacinian corpuscles structure
Large, ovoid structures (> 1 mm)
Pacinian corpuscles are prominent in (2) to detect (2)
fingertips & around joints
mechanical & vibratory pressure
Pacinian corpuscles consist of
afferent N fibers surrounded by highly modified Schwann cells—form concentric lamellae separated by fluid-filled spaces
Ruffinicorpuscles
small dermal mechanoreceptors
Ruffini corpuscles are especially common in
soles of feet
“free” N endings—most numerous, present in (2) surround most
epidermis & papillary dermis—surround most hair follicles
Ruffini corpuscles lack ((2)
connective tissue capsule & associated Schwann cells
Serve multiple sensory modalities—(4)
heat/cold, touch, pain, movement
Merkel cells
epidermal cells derived from neural crest
Merkel cells look like
melanocytes
where are merkel cells located?
stratum basale
what do merkel cells contain?
dense core granules
Pressure sensitive mechanoreceptors, associated with
free afferent N endings
