Secretion Flashcards
what are the 3 components of saliva?
water
electrolytes
organic components
what produces primary secretion?
acinus
where is primary secretion midified?
striated duct
what change in composition happens within the striated ducts?
conversion from isotonic to a hypotonic solution
resorption of Na and Cl
secretion of HCO and K
What is the role of bicarbonate?
plaque acid neutralisation
at rest, what are striated cells impermeable to?
water
what happens when saliva flows through striated ducts?
increase K concentration
decrease Na concentration
decrease Cl
what is the effect of slow saliva rate on Na concentration?
much time for resorption of Na so low levels in saliva
what is the effect of high saliva flow rate on Na concentrations?
less time for resorption of Na so less in saliva
what happens when there is high gland activity?
increased HCO in saliva
where does most of the formation and secretion of organic components in saliva occur?
acinar cells
what type of ducts is there little change within?
intercalated
what type of ducts is there large change in composition in?
striated
when doo striated ducts change composition?
conversion from isotonic to a hypotonic solution, resorption of Na and Cl, secretion of HCO and K
at rest, what cells are impermeable to water?
striated cells
what happens to Na and K concentrations as saliva flows through striated ducts?
increase K concentration
decrease Na concentration
Cl also decrease as follows Na
what adds HCO to saliva secretion?
Cl/HCO exchanger
what is the outcome of adding HCO to saliva secretion?
pH buffer
how does a low flow rate effect Na concentration?
very low Na in saliva
due to much time for resorption
how does high flow rate effect Na concentration in saliva?
less reduction of Na in saliva
due to less time for resorption
what increases in saliva with high gland activity?
HCO
what forms and secretes organic components?
mainly acinar cells
where is protein synthesised?
ribosomes on the RER
what does protein synthesis require?
ATP from mitochondria
where is protein transferred to?
golgi apparatus
what happens after protein is transferred to golgi apparatus?
exocytosis
what are the types of exocrine secretory mechanisms?
merocrine
apocrine
holocrine
what is merocrine secretion?
classical “exocytosis”
no loss of cell itself
predominant mechanism in saliva
what is apocrine secretion?
loss of part of the cells
e.g., in some sweat glands
what is holocrine secretion?
loss of whole cell
e.g., in sebaceous glands
what controls secretory mechanisms?
autonomic nervous system
where would you find the pre-ganglionic neuron and where does it synapse?
brain/ spinal cord
synapses in a ganglion
where would you find the post-ganglionic neuron and where does it terminate?
the ganglion
terminates in the effector organ/ tissue
what are the transmitters in the sympathetic autonomic pathways?
acetylcholine - pre ganglionic
noradrenaline/ acetylcholine - post ganglionic
what are the transmitters in the parasympathetic autonomic pathway?
acetylcholine - post ganglionic
what is the relationship between parasympathetics and sympathetic in control of saliva secretion?
not reciprocal
what do parasympathetics do in saliva secretion?
increase secretion
vasodilation
what do sympathetics do in saliva secretion?
alpha1 and beta2 adrenergic receptors
increase secretion
vasoconstriction
what cranial nerve targets the lingual gland?
IX
what ganglion is associated with the lingual gland?
remaks
what cranial nerve targets the parotid gland?
IX
what ganglion is associated with the parotid gland?
otic
what cranial nerve is associated with the sublingual gland?
VII
what cranial nerve is associated with the submandibular gland?
VII
what cranial nerve supplies the palatal gland?
VII
what ganglion is associated with the sublingual and submandibular glands?
submandibular
what ganglion is associated with the palatal gland
pterygopalatine
what is the receptor of parasympathetic control of saliva secretion?
muscarinic
what is the antagonist of parasympathetic control of saliva secretion?
atropine
what is the result of parasympathetic control of saliva secretion?
- Increase K permeability of acinus.
- First stage in acinar ionic secretion
- Responsible for most of the increase in volume of saliva flow
- Small, variable increase in organic components
- Contraction of myoepithelial cells
what is the result of sympathetic control of saliva secretion?
increased exocytosis of organic components
contraction of myoepithelial cells
what does stress induce?
induces sympathetic, so thick, low volume saliva. No parasympathetics
when is freys syndrome likely to occur?
post parotid surgery
what is freys syndrome?
Damage to auriculotemporal nerve
- Parasympathetic to salivary glands (Ach)
- Sympathetic to facial sweat glands (Ach)
Regeneration of damaged nerves
- Nerves mixed and misdirected.
- Salivary nerves – sweat glands.
Salivary stimulant (gustatory)
- Activation of sweat glands – sweating
Gustatory sweating
what are signals that initiate saliva flow?
- Reflex salivation – gustatory afferents (taste)
- Mechanoreceptive afferents (PDL, mucosa, joint and muscle)
- Ipsilateral (saliva flow increases on the side you chew on).
