saliva and gastric secretions Flashcards
what are the functions of saliva
lubrication for swallowing and speaking
mineralisation of teeth (high ca and increase ph to prevent from acid damage)
maintenance of oral hygiene - saliva contains lysosomes with peroxides to destroy bacteria
digestion - amylases for carbs and lapses for fats but only get activated in the stomach in the low ph
salvation for taste
what does lactoferon in saliva do
removes iron to stop growth of bacteria
what is xerostomia
dry mouth due to lack of saliva causing increase in gum disease and cavities
what are the three salivary glands
submandibular
parotid
sublingual
what is released from the submandibular
70% secretions
both mucus and serous fluid
what is mucus made up of and what from
viscous fluid made up of glycoproteins from mucus cells
what is released from the parotid gland
25% secretions
mainly serous fluid
what is released from the sublingual gland
5% secretions
mainly mucin release
how much saliva is produced per day
1.5 L
what are acini
bulb like cluster of epithelial cells that secret primary secretion fo salvia into a ductal system
what is the anatomical order or movement of salvia from acini to the mouth
acini - intercolated duct - striated duct - excretory duct
what is in primary secretion
Na hco3 - K water cl
what is the role of the intercolated duct
constrict and dilate to control flow of saliva
what helps myoepithelial cells to release saliva
contain smooth muscle which dilates and contracts
where does modification of saliva take place
in the striated duct
what happens in terms of ions and water occurs in the striated duct
solution is hypotonic as duct epithelial cells have poor permeability to water
na and cl is reabsorbed
more k and hco3 is secreted into the duct
when is saliva like plasma
primary secretion is most similar to plasma conc of inorganic ions
what happens to saliva during low flow rates
hypotonic and allows time for absorption and secretion of ions
what happens to saliva in fast flow rates
less time for reabsorption so more na cl and bicarbonate - salvia less hypotonic
what happens to Na cl k and hco3 in high flow rates of saliva and what is the highest to the lowest in conc
k stays the same and the rest increase
na - bicarbonate - cl - K
what effect to para symp and sympathetic have on flow rates of saliva
both increase saliva flow rates
what effect does the para symp have on saliva
increase ach release from nicotinic receptors causing contraction of myoepithilial cells increase secretion - this also releases VIP which causes vasodilation so more o2 for contraction of smooth muscle
what effect does symp have on the saliva
symp increases NA and A which targets adrenocepters causing contraction of the myoepithelial cells increasing secretion
what three other factors other than nervous input cause increase in saliva
cephalic reflex (pavlova dogs)
food in the mouth
chewing
what factors inhibit saliva flow
fear
dehydration
mental effort
what is sialadentits, symptoms cause and treatment
infection of submandibular or parotid gland mainly affect those with a dry mouth or dehydrated (decreased flow of saliva) can be due to malnourishment or immunosuppressants
fever, chills, redness and tenderness
what are the symptoms cause and treatments of sjorgns syndrome
autoimmune condition affecting the saliva glands
dry mouth and dry eyes cough and numbness
genetic disorder or virus and bacteria infection
use antihistamine, artificial tears/ punctual plugs, chewing gum
what are the functions of gastric secretions
protection of the stomach from high acidity via secretion of bicarbonate activation of enzymes digestion of proteins absorption of VIT B12 protection against food bourne infection
from top of the pit to the bottom name the cells of a gastric pic
surface mucus cells stem cells mucus neck cells d cells ecl cells parietal cells chief cells g cells
what do surface mucus cells do
secrete mucus and bicarbonate
what do D cells do
secrete somatostatin
what do chief cells do
secrete pepsinogen which is converted to pepsin in low ph
what do g cells do
secrete gastrin
what do ecl and parietal cells do
ecl = histamine
parietal cells secrete HCL and intrinsic factor
what does intrinsic factor do
aids in absorption of vit b 12
what inhibits the pumping of H+ into the stomach
omeprazole - antacid
what do mucus do to protect the stomach and what stimulates release
traps bicarbonate to neutralise acid
prostaglandins
what inhibits prostaglandins
aspirin and ethanol
what stimulates parietal cells to release acid
histamine from ecl cells
gastrin from g cells and gastrin stimulates ECL cells
ACH has direct input on parietal cells
ACH also increases vagus activity which stimulates g cells to release gastrin
what blocks histamine release
cimetidine
what blocks acid release from parietal cells
omeprazole
describe the negative feedback from acid secretion in the stomach
high acidity stimulates d cells to release somatostatin which stops histamine and gastrin release but has no effect on direct stimulation on parietal cell via ach
what are the cephalic reflexes of acid secretion
fear and depression reduce acid secretion
anger and tension increase secretion
food in the mouth increases secretion
what are the gastric effects on regulation of acid secretion
distention increases acid secretion (vaso-vagal)
hypertonicity
alcohol and aa
what stimulates pepsinogen release
CCK, gastrin, secretin and ACH from vagus nerve
why do we need intrinsic factor, where does it come from and what are the defect treatments
need it for absorption of VIT B12
released from parietal cells
deficit causes pernicious aenemia
treatment is cyanocoalabin injection
