W4 -Salivary Glands Flashcards
What are the 3 major salivary glands?
Parotid, submandibular and sublingual
The parotid is the largest and produces 30% of the saliva, what is the main duct used in the parotid after the secretion has passed through the intercalated ducts?
Stensen duct
Submandibular is the second largest and sits on the oral cavity, it accounts for 60% of saliva, what os the main excretory duct in the submandibular?
Wharton duct
Sublingual gland is the smallest and produces around 5% of saliva, where is it positioned?
Beneath mucous membrane in floor of mouth
Other than the parotid/submandibular/sublingual glands what else produce saliva continuously under local control? (either always on or always off)
Several minor salivary glands
What do the major glands secrete saliva in response to?
Parasympathetic activity - physical, chemical and physiological
What 4 things are within saliva?
Mucous, enzymes, antibodies and inorganic ions
What determines the overall composition of saliva?
What gland is most active
What are the 6 functions of saliva?
Lubrication, buffering, maintains tooth integrity, antibacterial function, taste and digestion
There are two mucins involved in the lubrication in the oral cavity/oesophagus produced by the salivary glands, MG1 and MG2, what differentiates them from each other?
MG1 - high molecular weight and high glycosylation, MG2 - low molecular weight and low glycosylation
In terms of the antibacterial function, what do MG1 and MG2 do to maintain tooth integrity?
They bind to teeth to prevent bacteria attaching to the enamel
Saliva has a role in taste and digestion too, what is this?
Activates the taste buds
Does para/sym stimulation provoke lots of saliva or small/no flow?
Para - lots of saliva, Symp - small (rich in protein)/no flow
Para innervation of salivary glands is via cranial nerves, what nerves control the parotid/subman/subling glands (still looking at para innervation)?
Parotid - glossopharyngeal, Subman/ling - both by facial nerve
What ganglion does the glossopharyngeal nerve and facial nerve to innervate the glands?
Glosso - otic ganglion, Facial - submandibular ganglion
Sympathetic innervation takes place via the???
Preganglionic nerves
During salivary secretion what happens to the blood flow and ultrafiltration from the plasma?
Blood flow around secretory acini increases and ultrafiltration enters the acini
Filtrate from the cells enter the lumen of the acinar cells, what does this mix with to create the primary secretion?
Mucus and alpha amylase
The primary secretion is modified as it passes through the ducts into the mouth, what is the enzyme that is added from the ebner glands of the tongue to the saliva once it’s in the mouth?
Lingual lipase
What structure does the salivary secretory unit consist of that are composed of serous or mucous secretory cells or both?
Terminal, branched, tubulo-acinar structure
Serous cells often form semilunar caps in mixed secretory units, what are these called?
Serous demilunes
The terminal secretory units merge to form ??? which are lined by secretory cells and drain into ???
Intercalated ducts, striated ducts
Serous cells have zymogen granules and their nuclei are basally located + rounded, what do they produce?
Enzymes
Mucous cells have mucigen granules and produce mucus, where are their nuclei found?
Flattened against the BM
Salivary glands can have adipocytes are divided into many lobules, what are these divided by?
Fibrous septae
Myoepithelial cells are support cells and surround the acini to force secretions from the ???? into the ???
Acinar lumen to the duct system
Where are excretory ducts found and alongside what?
In fibrous septae and alongside arteries/veins
Striated ducts are lined by tall columnar cells with darge nuclei, what is it that causes the basal cytoplasm to appear striated?
Basal interdigitations of adjacent cells and columns of mitochondria
PArotid glands are mainly serous cells and have large striated ducts to convert saliva to hypotonic solution, what is secreted (what is it rich in)?
Thin watery secretion rich in enzymes and antibodies
The striated ducts extend the area of membrane available for water/ion exchange, the duct epithelium also secretes???
Lysozyme and immunoglobin
Submandibular glands consist of a mix of serous/mucous cells and have serous demilunes, what are their secretory units called?
Seromucous secretory units
One of the enzymes produced by serous cells is amylase, what does this breakdown?
Starch
Mucous cells secrete mucin this aids in lubrication of the food bolus as it travels through the ???
Oesophagus
Sublingual glands ate mainly composed of mucous cells, the ductal system has no striated ducts, where does the secretion exit?
8-20 excretory ducts
Myoepithelial cells have long processes that extend around the acinus, where are the myo cells located?
BEtween basal plasma membrane of secretory cells and the BM
What is the cell composition like in the parotid, submandibular and sublingual glands?
Parotid - mainly serous, Submand - mixture, Subling - mainly mucous cells
