salivary secretion Flashcards
What are the constituents of saliva?
- water
- electrolytes
- organic components
mechanisms & control of salivary secretion
- Initial acinar secretion of H2O and electrolytes
- ductal modification of primary saliva
- secretion of organic components
- control of secretory mechanisms
describe primary acinar secretion
- Ionic concentrations similar to plasma
- Concentrations unaffected by flow rate
- Will undergo modification in the ductal system
Describe ductal modification
- little change in intercalated ducts
- large change in composition in the striated ducts:
- conversion from isotonic to a hypotonic solution
- resorption of Na+ and Cl-
- secretion of HCO3- and K+
- dependant upon flow rate
describe the effect of flow rate (low flow rates)
- much time for resorption of Na+
- result very low (Na+) in saliva
describe the effect of flow rate (high flow rates)
- less time for resorption of Na+
- result less reduction (Na+) in saliva
effect of flow rate
high gland activity
- increased HCO3- bicarbonate in saliva
formation of organic components
synthesis of protein in association with ribosomes on the RER requires ATP from mitochondria
describe autonomic nervous system
the sympathetic and parasympathetic divisions of the ANS often work in a opposing fashion to maintain homeostasis
describe parasympathetic
coordinates the body’s basic homeostatic functions
- conserves energy and maintains basal homeostasis
- pre-ganglionic neurons from brainstem and S2-S4
describe sympathetic
coordinates the body’s response to stress, associated with fight, flight and fright reactions
- pre-ganglionic neurons from T1-L2
What is a ganglion?
collection of nerve cell bodies in the periphery
describe one of the neuron peripheral chain
Pre-ganglionic neuron
- originates in brain or spinal cord
- synapse in a Ganglion
describe another of the neuron peripheral chain
Post-ganglionic neuron
- originates in the ganglion
- terminates in the effector organ/tissue
sympathetic control of salivary secretion
target transmitter: noradrenaline
- does not inhibit salivary secretion
- increased exocytosis of organic components
- contraction of myoepithelial cells
