salivary glands 2 Flashcards
what similarities do serous, mucous, and mixed all share?
A) comprised of a cluster of acinar cells surrounding a central lumen
B) spaces between cells (inter-cellular spaces) and the cells are also joined by tight junctions
C) tight junctions and intercelluar spaces allow the passage of water and small ions but restrict the passage of larger molecules
T/F: the end of the acinar cell that faces the lumen contains secretory granules
true
Surrounding the acinar cells is another type of cell called a __________ cell
myoepithelial cell
what surrounds the myoepithelial cell? (the final layer of the end piece)
basal lamina
Serous (acinar) cells: what are their basic characteristics?
- pyramidal shape
- short, irregular microvilli
- protein secreting (but NOT large amounts of mucin)
- well defined protein machinery (rER, Golgi, secretory granules, lumen)
mucous cell- basic characteristics
- cuboidal shape
- oval nuclei pressed toward base (toward basal lamina)
- arranged in tubules around a central lumen
- secrete mucins
- secretory granules are pale staining
- mucous granules occupy most of apical cell facing the lumen
what are serous demilune?
serous cells that lay on top of mucous cells
-they are found next to the basal lamina & nucleus of the mucous acini cells
** this arrangement may be caused by fixation techniques and not normally found in living tissue. when freeze dried, the mucous cell’s nucleus is not compressed, and the serous cells are next to (not on top of) the mucous cells
which type of cell is associated with both serous and mucous acini, as well as with the intercalated ducts?
myoepithelial cells
a myoepithelial cell is a specialized _________ cell with _________ properties
specialized epithelial cell with contractile properties
what is the role of myoepithelial cells?
facilitate movement of saliva into the ductal system
-they are under neural control
myoepithelial cells have many _________ that wraps around the multiple secretory cells that make up the acinus
processes
what are the 3 types of ducts associated with salivary glands?
1) intercalated
2) striated (secretory)
3) excretory (collecting)
major salivary glands contain which types of ducts?
all 3 major types
In the major glands the acini open into the _________
intercalated ducts
where do intercalated ducts empty into? (in major glands)
striated ducts
-from the striated ducts, they go to the excretory ducts
where do the excretory ducts empty into?
the oral cavity
what is the major difference between major and minor salivary duct drainage?
- In the minor gland, intercalated ducts are sometimes observed, striated ducts are not present
- in minor ducts, the acinus empties directly into an excretory duct
- unlike the major glands there are many, many excretory ducts associated with a given minor gland
intercalated duct: basic characteristics
- smallest ducts
- several acini drain into intercalated ducts
- short duct length
- cells are cuboidal with central nucleus
- secrete a few antimicrobial proteins
*Note how much larger the lumen is in the intercalated ducts than the lumen is in the acini (easy way to distinguish)
striated ducts: its functions
- longer, more active duct (than intercalated)
- SITE OF REABSORPTION….. converts isotonic saliva to hypotonic (requires ATP)
- SITE OF SECRETION- proteins & bicarbonates
striated ducts: basic shape/characteristics
- columnar
- highly polarized
- short microvilli
- **numerous foldings on basolateral membrane
- prominent mitochondria
what is the pathway for reabsorption in striated ducts?
the sodium and chloride ions in the primary secretion of the lumen get taken up at the apical end of the striated duct cell, then are transported through the cell to its *basal aspect where they pass to capillaries
T/F: excretory ducts are a series of connecting ducts that become progressively wider
true
how does the cell type of excretory ducts change?
changes from single epithelial layer to pseudostratified epithelium
-sometimes the final part of the duct becomes stratified & keratinized
what is the primary purpose of excretory ducts?
carrying the saliva to the oral cavity- no notable secretion or reabsorption occurs here
