Epithelial Glands I & II Flashcards
what is glandular tissues composed of
epithelial cells specialized for a secretory function
what are examples of exocrine glands
salivary glands, mammary glands, sweat glands, sebaceous glands, liver pancreas
define endocrine gland
when the epithelial down growth degenerates and laves the secretory tissue isolated from its parent epithelial layer
what are examples of endocrine glands
pituitary, thyroid, pineal, parathyroids, adrenals, gonads, liver and pancreas
where do endocrine glands secrete their product
into surrounding blood vessels
do endocrine or exocrine glands lack ducks?
endocrine
define exocrine
epithelial outgrowths into underlying connective tissue that retain their connection to the overlying epithelium in the form of one or more ducts
where do exocrine glands release their product
onto the surface
define paracrine
secretion affects neighboring cells
what does autocrine secretion affect
the cell that released the secretory product
what is the difference between simple and compound multicellular glands
simple do not exhibit ductal branching while compound do
what are the 3 types of tubular glands
straight, coiled, branched
what are examples of alveolar (acinar) glands
meibomian glands of the eyelids
sebaceous glands of the skin
what are examples of tubuloalveolar glands
salivary glands
brunner’s glands of duodenum
mucous glands of esophagus
describe serous secretion
- watery, enzyme filled
ie: parotid salivary gland
describe mucous secretion
thick, mucin-containing secretion
describe mixed secretion
*combination of serous and mucous
acinus is typically mostly mucous capped by a half-mooned shaped group of serous cells forming a serous demilune
ie: submandibular and sublingual glands
what are the 3 classifications of glands based on mechanism of secretion
merocrine
apocrine
holocrine
describe merocrine (eccrine) secretion
secretory product is typically stored in membrane-bound vesicles, and cytoplasm/cell membrane is retrieved in an exocytosis/endocytosis cycle
*includes most glands
describe apocrine secretion
apical cytoplasm is released along with secretory product
ie: axillary sweat glands
describe holocrine secretion
entire cell is released as part of secretory product
ie: sebaceous glands
what is the difference between the submandibular gland, sublingual, and parotid glands
submandibular:
*both serous and mucous cells
* serous cells form serous demilune capping mucous acne
*myoepithelial cells surround acini
sublingual:
* mucous acini
*flattened nuclei at basal poles of cells
*myoepithelial cells surround acini
parotid:
*serous acini
*apical regions contain zymogen granules
*RER predominates in basal regions of secretory cells
define lobules
subunits in a compound gland (multicellular gland)
*equivalent to branched gland
define parenchyma
the components of the gland derived from epithelium
define stroma
the connective tissue capsule surrounding the entire gland as well as the connective tissue partitions separating the lobules and lobes
define septa
extensions of the capsule into the epithelial components of the gland that divide into subdivision called lobules and lobes
define lobe
subdivision of a compound gland separated from adjacent lobes by septae
define lobule
subdivision of a lobe
- separated from each other by delicate septa
- each lobule is equivalent to a simple, branched gland
define acinus
secretory components of a lobule
*basement membrane covers outer surface
where are myoepithelial cells found
between the basement membrane and the secretory cells of the acinus
what are myoepithelial cells characterized by
extensive actin bundles resulting in contractility
what do myoepithelial cells do
help to express the secretions of the acini into the intercalated ducts
define intralobular ducts
- ducts that lie within a lobule
* joined by confluence of 2*interlobular ducts
what are characteristics of intercalated ducts (in intralobular)
- drain the secretory acini
- lined by simple squamous epithelium transiting into low cuboidal epithelium
- involved in bicarbonate/chloride ion exchange
what are characteristics of striated ducts (in intralobular ducts)
- lined by cuboidal epithelium transitioning to columnar epithelium with basal striations (for active transport)
- actively reabsorb sodium ions; passively reabsorb chloride ions; actively secrete potassium ions
define interlobular ducts
- formed by the confluence of 2+ striated ducts and are found in the septa between adjacent lobules
- lined with pseudo stratified columnar epithelium
define lobar duct
- formed by the confluence of 2+ intralobar ducts
* lined with striated columnar epithelium
what are parotid glands composed of
only serous acini
what are submandibular glands composed of
both mucous and serous acini, but serous acini are predominant
what are sublingual glands composed of
both mucous and serous acini, but the mucous acini are predominant
