exocrine glands Flashcards
endocrine glands
synthesize and release hormones to be transported in the blood to target cells
OR released into extracellular fluid
exert paracrine or autocrine effects
Exocrine
make hormones that are conveyed in epithelial lines EXCRETORY ducts
what do tumors like adenomas and adenocarcinomas develop from?
glands
how are exocrine glands classified?
by what they secrete
how they secrete it
cell numbers
what are the four classifications of exocrine glands based on secretion type?
sebaceous- waxy, oily
serous-watery with enzymes
mixed- mucus and serous combo
mucus-mucus, thick and can serve as a plug
mucus glands
-examples?
type of exocrine gland that secrete large glycosylated proteins called mucinogens
when hydrated, the mucinogens become viscous and are called mucin
-examples: goblet cells, and mucous cells of stomach
serous glands
-examples?
type of exocrine gland that secretes watery, enzyme hormones
ex: parotid gland and exocrine pancreas
mixed glands
-ex?
type of exocrine gland with serous and mucus secretory units
ex: submandibular and sublingual gland
sebaceous glands
-Ex?
- waxy, oily secretions called sebum
- skin glands- acne vulgaris
how are exocrine glands classified based on mode of secretion?
- merocrine- exocytosis with no loss of cytoplasm or plamalemma
- MOST COMMON
- apocrine- pdt released along with apical cytoplasm and apical plamalemma
- holocrine- secretory pdt released with ENTIRE CELL -usually used with sebacous glands
what are the classifications of exocrine glands based on cell numbers?
1) multicellular- can be released either a) as organized secretory sheets or b) as secretory tubules or c) as secretory units and ducts
2) unicellular- as individual secretory cells -found in epithelium (ex-goblet cells)
how are multicellular exocrine glands that have secretory units and ducts further classified?
based on shape and duct system
what are the exocrine multicellular glands classification based on shape
acinus- aka aveolous (circular)
tubular (tube like)
where would you most likely find goblet cells?
small intestine and trachea
how do you know that you are looking at a mucus cell?
have a white space with nucleus pushed to periphery
nucleus is flat
how do you know that you are looking at a serous cell?
circular nucleus, acidophilic cytoplasm
how do you know that you are looking at a sebaceous gland?
has circular nucleus that is centrally located but has clear cytoplasm like mucus cell
what types of cells are associated with acne vulgaris?
sebaceous glands are associated with hair follicles. follicles become clotted and we get inflammatory cells (basophilic) and often giant cells (associated with chronic inflammation)
-also get collagen production locally that can cause disfiguration
what types of duct systems exist for multicellular glands?
1) simple- single, unbranched excretory duct -some glands don’t even have a duct
2) compound- branching ducts that converge to form a single duct that opens onto the epithelial surface
how are multicellular glands divided ?
into LOBES made by the collagenous capsule that surrounds them and the septa then continue to divide the lobes into LOBULES
what are the classifications for multicellular ducts
intralobular ducts-in the lobule -intercalated and striated
interlobular- found in connective septa that separate lobules
myoepithelial cells
- surround multicellular glands and small ducts and act as contractile cells that express secretion
- contain actin and myosin
- connected to epithelial cells via desmosomes and gap jxns
how do you identify a striated, intralobular duct?
- mitochondria that form striations with nuclei pushed to apical domain of the cell
- if no striations, just looks at the acidophilic nature of the cytoplasm
what type of secretion, ducts, shape of secretory unit and cellular component does the parotid gland have?
secretion: serous
duct: compound
shape: acinar
multicellular
have interlobular and intralobular ducts with intercalated and striated ducts
