salivation Flashcards
difference between extrinsic and intrinsic salivary glands
extrinsic- not found in oral cavity (use ducts)
intrinsic- found in oral cavity
extrinsic salivary glands (90%)
parotid
submandibular
sublingual
intrinsic salivary glands (10%)
buccal
labial
palatine
types of cells in extrinsic salivary glands
parotid - serous
submandibular- serous and mucous
sublingual - primarily mucous, some serous
types of cells in intrinsic salivary glands
primarily mucous cells
where does the parotid gland empty
empties via the parotid duct into the 2nd maxillary molar
where does the submandibular gland empty
empties via wharton duct to the lingual frenulum
where does the sublingual gland empty
has 10-20 ducts, empties on floor of the mouth
what nerve innervates the submandibular and sublingual glands
facial nerve(CN VII), coming from the superior salivatory nucleus. exits skull through internal acoustic meautus
what nerve innervates the parotid gland
glossopharyngeal nerve(CN IX), from the inferior salivatory nucleus. exits skull through jugular foramen
what receptors in the oral cavity stimulate saliva production
chemoreceptors (e.g. acidity)
mechanoreceptors (e.g. chewing)
what pathway do CNVII and CNIX increase salivary volume by?
parasympathetic pathway
how does the sympathetic nervous system effect the extrinsic glands
via the superior cervical ganglion (SCG) originating from T1-T4, makes thicker protein-rich saliva
what does the parasympathetic nervous system primarily secrete?
acetylcholine
what does the sympathetic nervous system primarily secrete?
noradrenaline
how does water enter the acinus of the gland?
through aquaporin V across apical membrane
through paracellular transport
through aquaporin III on the basolateral membrane into acinar cells, then aquaporin V
how does sodium enter the duct
paracellular transport between acinar cells
how does potassium enter the duct
potassium-hydrogen pumps
through potassium leakage channels
how do chloride ions enter the duct
CFTR proteins
how do bicarbonate ions enter the duct
when calcium and water combine in the presence of carbonic anhydrase bicarbonate ions formed, bicarbonate enters and some chloride may leave
what are the amounts of chloride and sodium ions pulled into the duct equal to
the amount of water in the duct - acinus is isotonic to blood plasma
what is the secondary secretion in relation to the blood plasma
hypotonic - sodium and chloride ions re-enter acinar cells, so less solutes
acetylcholines effect
binds to M3 receptor
stimulates Gq protein, binds to GTP
stimulates PLC enzyme
this breaks down PIP2 into DAG and IP3
IP3 stimulates an increase in calcium levels
DAG activates protein kinase C
calcium activates CAM kinases to phosphorylase channels, increasing secretion of substances into the acinate
noradrenaline effect on glands
binds to beta receptors on acinar cells
activates Gs protein, which is bound to GTP
stimulates an effector enzyme on the cell membrane - adenyl cyclase converts ATP to cAMP
cAMP activates protein kinase A
protein kinase A stimulates exocytosis of granules
releases mucin and salivary amylase (increasing protein content)
can also cause vasoconstriction, deceasing electrolyte and water secretions from the blood
overall functions of saliva
oral hygiene
antimicrobial
chemical digestion
hydrate the oral cavity
increase taste of substances
decreases incidence of cavities
what antimicrobial substances does saliva contain
IgA antibodies
cystatins
histatins
lysozymes
proline rich proteins
