Skin- glands Flashcards
what are the 3 types of glands
-sebaceous glands
- merocrine (eccrine) glands
-apocrine glands
describe sebaceous glands
alveolar, holocrine glands, consisting of branched acini
how much of the cell is secreted in sebaceous glands
the entire cell
how many sebaceous glands are associated with a hair follicle
one or more, develop as outgrowths of external root sheath
what do sebaceous glands look like on a slide
foamy, almost like brown fat
what do sebaceous glands secrete and via what
oily sebum via pilosebaceous canal
what does the pilosebaceous canal contain
high in lipid content and cell debris
what is the function of sebum
used for waterproofing, moisturizing skin and hair
where are pilosebaceous canals also found
on non-haired transitional skin where they secrete sebum directly onto skin surface
what is seborrhea
excessive secretion of sebum
what makes a pilosebaceous unit
a hair follice and its associated arrector pili muscle and sebaceous gland
describe sweat glands
simple, coiled, tubular glands surrounded by myoepithelial cells, assist in secretion
what are the 2 types of sweat glands
merocrine and apocrine
what do follicle mites do
feed on sebaceous gland secretion on skin to keep sebaceous glands clear
what do merocrine glands secrete
only product
where are merocrine glands located in the body
most of body surface except lips and genitalia
where are merocrine glands located on a slide
deep dermis or subcutis
describe merocrine glands
unbranched, coiled, tubular glands with 1-2 layers of cuboidal to columnar epithelium with excretory ducts
what do merocrine glands secrete
sweat onto skin surface via sweat pore on epidermal ridges
what does sweat contain
hypotonic solution of salts, ammonia, urea, uric acid
what is the function of sweat
thermoregulation for evaporative cooling
where does body lose sweat from
600 ml/day from lungs, skin and mucous membranes
what part of the ANS is thermoregulatory sweating
cholinergic/parasympathetic
where does thermoregulatory sweating occur
first in axillae, then forehead and scalp, then hands and feet
what part of the ANS is emotional sweating
adrenergic/sympathetic
where does emotional sweating occur
palms and soles
what is the alternative explanation to sweating
sweat glands innervated by sympathetic but use cholinergic nerves and dont use adrenaline
what do apocrine sweat glands secrete
product along with some cytoplasm
describe apocrine sweat glands
coiled, tubular with large dilated lumina
where are apocrine sweat glands located
in axillae, groin
when do apocrine sweat glands develop
at puberty
describe the epithelium in apocrine sweat glands
secretory, cuboidal epithelium, 2-3 cell layers thick, surround large glandular lumen
describe the secretions of apocrine glands
thick, viscid secretions into hair follicle that contain proteins, carbs, ammonia, lipids, and organic products
describe the odor of apocrine gland secretions
odorless when secreted but bacterial breakdown causes acrid odor
what is the secretion type in apocrine sweat glands
adrenergic
what type of glands are cerumen glands
apocrine
where do mammary glands develop
along paired epidermal ridges called mammary ridges or milk lines that extend from axillae to groin
what are mammary glands
highly modified apocrine sweat glands indentical in males and females until puberty
when and how do mammary glands develop in females
under influence of pituitary and ovarian hormones, following pregnancy, produce milk to feed young
what happens to mammary glands at menopause
atrophy and involute
what are inactive mammary glands composed of
dense, irregular collagenous CT, interspersed with adipose tissue and occasional smooth muscle
what are tubulo acinar glands organized into
secretory lobules
what are mammary glands drained by
terminal ducts that drain into lactiferous ducts which empty into lactiferous sinus in the region of the nipple
what is the areola
pigmented region around the nipple, stratified squamous epithelium with deep epidermal ridges
what glands do the areola contain
merocrine sweat and sebaceous glands
what happens to mamary glands during lactation
enlarge due to hypertrophy of secretory cells and accumulation of secretory product
what is colostrum and when is it secreted
-secreted first few days after birth
- an alkaline, yellowish secretion with high protein and salt content and low lipid and carbohydrate
-contains lots of Ab’s important in passive immunity
what produces milk
merocrine and apocrine
what secretes the protein portion of milk?lipid portion?
protein- merocrine
lipid-apocrine
what are meissner’s corpuscles
mechanoreceptors/touch receptors in dermal ridges of papillary layer
where are messner’s corpuscles located
hands, feet, lips genitalia
describe meissner’s corpuscles
cylindrical structures
- afferent nerve fibers associated with minimally modifed scwann cells
what are pacinian corpuscles
mechanoreceptors located in dermis and hypodermis
where are pacinian corpuscles located and what is their function
fingertips and around joints to detect mechanical vibratory pressure
describe pacinian corpuscles
- large ovoid structures
- consist of afferent N fibers surrounded by highly modified schwann cells to form concentric lamellae separated by fluid filled spaced
what are ruffini corpuscles and where are they common
small dermal mechanoreceptors, especially common in soles of feet
what sensory modalities do ruffini corpuscles serve
heat.cold, touch, pain, movement
describe ruffini corpuscles
-lack CT capsule and associated schwann cells
what do ruffini corpuscles contain and where are these structures located
free nerve endings - present in epidermis and papillary dermis, surrounds most hair follicles
what are merkel cells
epidermal cells derived from neural crest
describe merkel cells and where theyre found
look like melanocytes, located in stratum basale and contain dense core granules that store serotonin
what type of sensory receptors are merkel cells
pressure sensitive mechanoreceptors, associated with free afferent nerve endings and merkel discs
