Salivary Secretion Flashcards
What are the 2 key components of the salivary duct system, for salivary secretion?
acini and striated ducts
what is the function of the acini?
produces the primary salivary secretion
What is the function of the striated duct?
modifies the secretion
what is an electrolyte?
substances that have a natural positive or negative electrical charge when dissolved in water.
what are the constituents of saliva?
water
electroyltes (Na+, K+, Cl-, HCO3- (bicarbonate))
organic compounds
At resting, what is the Na+ and K+ concentrations inside and outside of the acinar cell?
Inside = Low Na+ and high K+
Outside = High Na+ and low K+
What happens when a nerve activates the acinar cell
- Causes an increase in membrane permeability to K+
- Facilitated by a calcium ion release
- Net affect - increase off all membranes to K+
- Because K+ conc is high inside the cell, K+ will leak out down its conc gradient - will go into the lumen
- Results in K+ into the primary secretion
- also results in an increase in K+ in the connectibe tissue side as well as the lumen
What does the increase in extracellular K+ activate?
This increase in extra-cellular K+ activated a co-transporter - this co-transports Na+, K+ and Cl- into the cell (active transport), triggered by the increase of K+ outside of the cell
The co-transporter, transports Na+, K+ and Cl- into the cell, what does this result in?
- increase in exchange, so the Na+/K+ works harder and transports Na+ out of the cell = no increase intracellularly of Na+
- opening of Cl- channels, and the increase of Cl- and K+ out into the lumen = into dalivary secretion, = shift in charge due to Cl-
When the Cl- is in the lumen, this causes a shift in charge, what is drawn into the secretion to balance this charge?
Na+ is drawn into the secretion between the cells to balance the charge
H20 is dragged down between the cells aswell to address the osmotic balance
True or false: the ionic concentrations of the primary acinar secretion is similar to plasma?
True
What is an isotonic solution?
a solution with the same water and solute concentration as body fluids
when the primary secretion going through the striated duct system, it goes from an isotonic solution to a …?
hypotonic solution - less concentrated solution
What constituent of saliva acts as a buffer?
HCO3- (bicarbonate)
What is resorbed in the striated ducts and what is secreted into the saliva?
resorption of Na+ and Cl-
secretion of HCO3- and K+