Salivation Flashcards
Approx how much saliva is produced a day and what’s the flow rate?
1L
resting = 0.5ml/min
maximal = 7ml/min
which gland makes the most fluid?
Which gland makes what secretion?
submandibular
parotid (20) - serous
submandibular (70) - mainly serous
sublingual (5) - mainly mucous
simple (5) - mucous
Acinar cells – what kind of secretion do they make relative to plasma? Are salivary proteins made?
isotonic
salivary proteins are made
Duct cells – What ions are reabsorbed, what ions are secreted? What’s it impermeable to? What does saliva become after passing this area relative to plasma?
Na and Cl reabsorbed
K and HCO3 are excreted
impermeable to water
hypotonic to plasma
What are the 3 types of ducts?
intercalated
striated
lobar/excretory
Why do Na+ and Cl- levels in the saliva have a lower concentration than K+ and HCO3- at a low flow rate? Why do they go up with flow rate?
because they get reabsorbed
reabsorption>secretion
as secretion>reabsorption with faster flow rate
What is K+ trend to flow rate, and why? Why doesn’t HCO3- follow the same trend as K+?
duct cells secrete more bicarbonate
bicarbonate is an active process, everything else is passive
Other than ions, what else is secreted?
mucous
proteins (IgA)
enzymes (amylase, lysozyme)
Is salivary production controlled mainly by hormones or nerves?
Where is the salivary centre?
neural
medulla
If the sympathetic NS is activated, what saliva is produced? What about PS?
SNS-mucous saliva
PNS-serous saliva
What’s the difference between simple and conditioned reflex?
simple:
Stimulation of receptors- found in the medulla – in the salivary centre.
Response is to increase activity of ANS
conditioned:
take place from higher centres. Activation without the sensory inputs
PS activation – makes serous saliva rich in what?
Describe how Kallikrien and bradykinin fit into the picture
Why do you get dry mouth in stage fright?
enzymes
Activation of PS stimulate release of kallikrein to create a peptide called bradykinin = vasodilation and capillary permeability increases so more blood escapes to pass between acinar cells to form the secretion
– Activated sympathetic leads to vasoconstriction – shuts off production via this mechanism – not enough fluid in the blood
Some functions of saliva?** 7 total
amylase - breakdown or polysaccharides produces mucous - swallowing protective - lysozyme, IgA solvent for taste moisturiser - speech oral hygiene contain bicarbonate - neutralises acids
What are the 2 phases of swallowing? Describe them.
Oropharyngeal
Food bolus is directed into eosophagus (requires sealing off nasal passages (by uvula) and the trachea (by the glottis)
Eosophageal
Eosophagus is protected from damage caused by passing food bolus by mucous secretion
Movement by peristalsis (gravity assisted)
why doesn’t food move up the oesophagus
peristalsis
