GI4 Flashcards
what are the lubrication components of saliva?
water
electrolytes
mucous
what are the bactericidal components of saliva>
antibodies
lysozyme
antimicrobial peptides
what are the digestion components of saliva?
amylase (herbi/omnivores) lingual lipase (juveniles)
what are the cooling components of saliva?
saliva spreading
what is the general structure of the salivary gland?
compound tubuloacinar gland
what is the tenecity of saliva in nonruminants?
hypotonic
what produces the primary secretion of saliva?
acinus
what part of the salivary gland has Na and CL reabsorption?
ductal
what is the tenecity of ruminant saliva?
isotonic
what type of secretion is from the parotid salivary gland?
serous
what type of secretion is from the submaxillary gland?
mixed serous/mucous
what type of secretion is from the sublingual gland?
mucous
salivary serous acinar cells secrete a ___ fluid that contains both ___ and _____
- isotonic
- Cl-
- HCO3-
salivary ductal cells reabsorb ___ and __ but not ___; final saliva is ____ relative to plasma.
- Na+
- Cl-
- water
- hypotonic
primary acinar scretions are ____
isotonic
Na+ absorption/modulated by what?
aldosterone
- ENaC
- Na+/H+ exchanger
ruminant saliva is high in ___, ___ and ___
-PO2-4, HCO3-, pH
conditions impeding salivation result in what in ruminants?
acidosis
what are PS stimulations of the salivary gland
- facial n
- glossopharyngeal n
- CHOLINERGIC reveptors
what are the sympathetic stimulations of salivary glands?
BETA receptors
is there endocrine regulation of salivation?
no
what is the glandular mucosa of the stomach?
cardia
corpus
antrum
what is the function of the surface epithelial cells of the stomach glands?
secrete thick mucous and HCO3-; protective function
what is the function of the mucous neck cells of the stomach glands?
secrete thing mucous; cells division
what is the function of the parietal (oxyntic cell) of the stomach gland?
HCl secretion; intrinsic factor secretion (require for B12 absorption)
what is the function of the stem cells of the stomach gland?
regeneration
what is the function of the chief (peptic) cells of the stomach glands?
pepsinogen secretion
what is the function of the endocrine cells (including enterochromaffin-like cells) of the stomach gland>
secrete regulatory substances (eg. somatostatin, gastrin, histamine, serotonin)
what are the properties of the glands of the cardia?
secrete only mucous
alkaline
protective function
what are the properties of the glands of the antrum?
- no parietal cells
- D cells (somatostatin secretion)
- G cells (gastrin secretion)
- chief cells (secrete pepsinogen)
parietal cells HCl secretion properties
- isotonic HCl secretion
- H+ extrusion is achieved actively
- HCO3- reabsorption; “alkaline tide”
___ and ___ enable release of histamine
- gastrin
- ACh
gastrin and ACh potentiate histamine release, thereby increasing __ ___ ___ __
-parietal cell HCl secretion
what is the role of somatostatin?
inhibition of histamine-stimulated HCl secretion
in the corpus, what two factors regulates somatostatin secretion?
neural and endocrine factors
in the antrum, what stimulates somatostatin secretion?
-low luminal pH and gastrin
somatostatin inhibits the release of what?
gastrin
pepsinogen becomes what?
pepsin (active form)
what causes more release of pepsinogen?
low pH and pepsin (positive feedback)
at pH
gastrin secretion falls
at pH
gastrin secretion ceases
what is the basal phase of gastric acid secretion?
interdigestive (smallest)
what is the cephalic phase of gastric acid secretion?
anticipatory response
-30%
what is the gastric phase of gastric acid secretion?
initiated by stomach distention
-50-60%
what is the intestinal phase of gastric acid secretion?
small but significant
-5-10%
what is the primary hormonal stimulus for acinar secretion?
CCK
what is the primary hormonal stimulus for ductal secretion?
secretin
