Section 7: Salivary and Gastric Secretion and Esophageal and Gastric Motility Flashcards
Cell types of salivary gland:
serous, acinar, and mucous cells
Functions of saliva:
protects and digests
Protective aspects of saliva:
mucus, HCO3-, and antibacterial enzymes
Digestive aspects of saliva;
alpha-amylase, Lingual lipase (neither are essential for digestion)
True or False? Alpha-amylase is essential for digestion while lingual lipase is not.
F. neither are essential
What type of glands are salivary glands?
exocrine
Surface epithelial cells of the salivary glands produce:
0.5 to 1.0 L, most productive gland of the body, isotonic NaCl, NaHC03, KCl
True or False? Saliva is always hypertonic.
F. Hypotonic (a solution in which normal cells will increase in volume)
pH of saliva at rest and when stimulated:
6 vs. 9
mOsm/L of saliva at rest and when stimulated:
575 vs. 200 mOsm/L
ion concentrations in plasma, most to least:
Na+, Cl-, HCO3-, K+
Ion concentration in saliva when stimulated, most to least:
Na+, HCO3-, Cl-, K+
What are the two components of the model of salivary secretion?
acinar cells produce primary secretion and duct cells modify secretion
Functional unit of any salivary gland:
The “Salivon”, blind end set of epithelial cells, acing region, smooth muscle cells to contract secretions
Ion concentration in saliva when not stimulated, most to least:
K+, Cl-, Na+, HCO3-
What is found in the end piece of a salivary gland?
amylase-containg primary secretion, nearly isotonic total he plasma)
Where does modification of ionic content take place in the salivary gland?
Striated and excretory ducts
What types of secretions are released from acing cells?
Plasma-like
What drives Cl- secretion into the acing lumen through apical-membrane Cl- channels?
Cl- electrochemical gradient created by large intracellular stores
What happened to the acing fluid as it flows through the ducts?
modified
What are absorbed and what are secreted in the salivary gland duct between Na+, Cl-, K+, and HCO3-?
unstimulated absorption: Na+ and Cl-, unstimulated secretion: K+, and stimulated secretion: HCO3-
Unstimulated absorption of ___ occurs in the salivary gland duct.
Na+ and Cl-
Unstimulated secretion of ___ occurs in the salivary gland duct.
K+
Stimulated secretion of ___ occurs in the salivary gland duct.
HCO3-
What nerve enters the Otic Ganglion?
Jacobson’s nerve and Tympanic Plexus
Parasympathetic input from fibers of this nucleus stimulates the parotid gland to produce vasodilation and secrete saliva.
inferior salivatory
What nerve innervates the submandibular ganglion?
facial nerve
What is the innervation to the parotid gland?
Auriculotemporal branch of the trigeminal nerve
Parasympathetic perganglionic fibers to the major salivary glands
Facial and glossopharyngeal nerves
Sympathetic preganglionic nerves originate here that supply the major salivary glands:
the cervical ganglion, postganglionic fibers from this extend to the gland in the periarterial spaces
What aspects of the salivary glands do the parasympathetic and sympathetic mediates regulate?
blood flow, ductular smooth muscle activity, growth, and metabolism (all know salivary gland functions)
From what vertebral level does the superior cervical ganglion arise?
T1-T3
Nervous control of salivary secretions:
psyche, taste, smell, food, chewing, and pain
How do taste, smell, food, chewing, and pain exert nervous control over the CNS?
via oral mechanical and chemical receptors
Which nucleus in the medulla controls salivary secretion?
salivary nucleus
Sympathetic receptors that control salivary secretion:
B-adrenergic receptors and alpha-adrenergic receptors
Parasympathetic receptors controlling salivary secretion:
cholinergic receptors
Where are cholinergic receptors located?
acing cells and duct cells
When is sympathetic innervation to the salivary secretions activated?
fear stimuli, “fight or flight”, scared spit-less
When is parasympathetic innervation to the salivary secretions activated?
meal stimuli
Attributes of salivary content with sympathetic nervous input:
low volume, high viscosity, high protein concentration, and very high mucin concentration
Attributes of salivary content with parasympathetic nervous input:
High volume, low viscosity, low protein concentration, and very low mucin concentration
Sjogren Syndrome:
chronic progressive autoimmune disease, antibodies to salivary and lacrimal gland cells, immunologic injury to acini reduces secretion, expression of Cl-/HCO3- exchanger in ducts is lost, dry mouth, keratoconjunctivitis, can lead to difficulty chewing, caries, difficulty with continuous speech, oral ulcers
True or False? There are significant levels of secretions in the esophagus.
F.
Gastic juices:
H+, water, pepsinogens, intrinsic factor (for B12 absortption)
Functions of acid:
kill bacteria, break chemical bonds in food, activate pepsinogen
Secreted volume of acid:
2-3 L/day
Name of stomach mucosa:
oxyntic gland mucosa
In which stomach chamber are oxyntic gland mucosa:
cardia/ corpus or body
True or False? Gastrin is released into the blood stream.
T
Gastric gland is aka:
Oxyntic gland
Mucous neck cells:
3.0 ml/min when stimulated, isotonic, HCl, KCl, IF
Oxyntic cells are aka:
parietal cells
Functions of duct cells:
modification of secretion s it flows into oral cavity
Why do we need bicarbonate in our saliva?
acid producing bacteria
Exocrine glands release where?
Outside the body, the lumen of ducts
Amount of flow of salivary secretions when maximally stimulated per minute
40 ml/min
F. Concentrations of Na, HCO3-, Cl-, and K+ all increase with stimulation of salivary glands.
K+ decreases
True or False? The osmotic content of saliva is low regardless of stimulation.
T
True or False? Secretions from the endpience are osmotically similar to the interstitial fluid by the end of the duct.
F
Is the change in osmolarity of secretions from the end piece an active or passive process?
passive
Acing cells producew
Interstiial fluid like secretions
The Na/K pump is always located on this side of the cell
basolateral membrane
Which ion is being recycled on the basolateral membrane of the acing cell?
K
Acetylcholine binds this type of receptor on the basolateral membrane of acing cells:
M3 receptors
What can move through the tight junctions in response to Cl- entering the lumen from the acing cells?
Na+ and water
ENac:
distal tubule of kidney and apical side of ductal cells of salivary glands
H/ K exchangers are located on which membrane of the ductal cells of the salivary gland?
apical
When is the H/ K exchanger most effective?
when plasma-like NaCl flow is slow
how to get Cl- out of the lumen and into he interstitial space?
CFTR channels and the Cl- channels on the basolateral side
Duct cells are capable of secretion lots of:
bicarbonate
What channels reduces sodium concentration in the plasma-like NaCl fluid flowing past duct cells of salivary gland?
ENac
As fluid flow rate increases:
bicarbonate concentration increases, M3 receptor is stimulated and Cl- is lost via CFTR (actively pumping bicarbonate into fluid)
True or False? The m3 receptor requires ATP.
F. It is an active process but does not require ATP
Stimulation of what receptor leads to he activation of bicarbonate channels?
M3 receptors on the basolateral membrane of the ductal cell
Sympathetic component to the glands:
norepinephrine release, nothing to do with a meal
Acetylcholine is released onto what cells to control the salivary gland?
duct or acinar cells
Cholinergic receptors are __ receptors.
M3 receptors
Why not to salivate when scared:
you may aspirate saliva and kill you if being chased by a lion
Affect of nonfunctioning Cl-?HCO3- exchanger:
dry mouth and eyes
special tube that carries food and medicine to the stomach through the nose:
nasogastric tube (NG tube)
What can elicit the same gastric juice composition as a meal/
histamine
How is the Na concentration affected when secretory rate increases?
decreases
2 mechanisms for H+ secretion from parietal cells:
increases in surface area and membranes H+ pump activated
The stomach is capable of producing a H+ gradient of ___ times.
1 million