Fan - Salivary,, Gaastric Nd Intestinal Secretions

Question 1

Why is It that that K+ and HCO3 are high in the saliva but Cl and Na are low?

Answer 1

All four ions are secreted by the acinar cells in the salivary glands. However, in the ductal area the Na and Cl are taken up whereas more K+ and HCO3 are actually secreted into the duct.
- Sidenote - tight junctions are really tight so water reabsorption doesn’t really follow the Na and Cl so it stays in. But the longer the saliva is in the ductal area the more water is reabsorbed slowly.

Question 2

How will all of the channels in the Acinar cell be activated/stimulated/

Answer 2

An increase in calcium coming from nerves

Question 3

What nerves. Control salivary secretion??

Answer 3

7 9 10

Question 4

What are the oxyntic ions? Non-oxyntic ions?

- Which ion will be in highest concentration in the gastric juice?

Answer 4

Oxyntic - H+, Cl-, K+
Non-oxyntic - Na+

• Cl

Question 5

What within the parietal cell is responsible for acid secretion?

Answer 5

Once the parietal cell is stimulated, the tubulovesicles rich in H+ pumps in resting parietal cells fuse with the intracellular canilliculi to release H+ in the stomach.

Question 6

What is the Mechanism of parietal cell secretion of H+ (and Cl-)?

Answer 6

When we get stimulation, Ca+/cAMP levels are increased, which causes activation of an H+/K+ pump, which pumps H+ into the lumen of the stomach and takes up K+.

• Ca/cAMP also increases Cl- channel so more Cl- is put into the lumen
• H+/K+ transporter is target for drugs

Question 7

Alkaline tide?

Answer 7

If you remember, after you eat you have all of this Cl- coming into the cell and then it is pushed out into the stomach lumen. Well, it is swapped for HCO3-. So, after a big meal pH in the portal vein will go down because you are secreting more HCO3- into it.

Question 8

What is the Proof That the cephalic phase induces HCL secretion?

Answer 8

Study with patients with stomas. The more they liked the food the more gastric secretions there were. People who self selected even had increasing gastric secretions after they finished eating.

Question 9

What ions are higher in saliva than plasma? Which are lower?

Answer 9

K+ and HCO3- are higher

Cl- and Na+ are lower