GI-Gastric Secretions Flashcards
The fundus and body contain … which is responsible for the secretion of HCl.
Oxyntic Gland Mucosa
The distal (antrum) contains … that produce Gastrin, and the Pyloric Gland Mucosa.
Endocrine G-Cells
What is the deepest portion of the Gastric Pit?
Peptic Cell Region
What type of cells are in the Peptic Cell Region and what do they produce?
Chief Cells; inactive pepsinogens (I and II)
What does the portion above the Peptic Cell Region, towards the stomach lumen, contain and what do they produce?
Parietal cells; HCl
What does the neck and opening regions of the gastric pit contain, the surface epithelium also contains this?
Mucus secreting cells
In the production of HCl in the Parietal Cells of the Gastric Glands, what mechanism is on the basolateral membrane?
Na/K-ATPase
In the production of HCl in the Parietal Cells of the Gastric Glands, what mechanism is on the apical membrane?
H/K-ATPase
HCO3- accumulates in the Parietal Cells and is exchanged across the basolateral membrane for …
Cl-
How is HCl formed in the gastric pit?
The Cl- within the cell (from exchange with bicarb) will follow the electrochemical gradient dictated but he movement of H+ across the apical membrane = HCl forming the gastric pit.
What are the most potent Secretagogues (stimulants) for HCl production and release?
ACh, Gastrin, and Histamine
In the 1 of 2 ways to inhibit HCl secretion: (pH regulation) Gastrin release from G-Cells is inhibited as acid (pH
D-Cells; Somatostatin
In the 1 of 2 ways to inhibit HCl secretion: As acid in the duodenum releases …, it will inhibit Parietal Cells directly reducing HCl production.
Secretin
What is the only thing that will inhibit D-Cells, stoping the inhibition of HCl production?
ACh
At what pH are Pepsinogens converted to Pepsin?
pH
Once active Pepsin demonstrates an … Activity by splitting … peptide bonds.
Endopeptidase; interior peptide bonds
What is the most potent and most important stimulator in the release of Pepsinogen?
ACh
What, released in response to Duodenal Chemoreception of acid will also stimulate the chief cells to increase production and release of Pepsinogen?
Secretin
In the acid environment of the stomach the released Vit B12, from proteins, binds to … which protects B12 from digestion.
Haptocorrin
Once the B12-Haptocorrin complex reaches the Duodenum and the pH becomes more neutral the … digest away the Haptocorrin.
pancreatic proteases
After the release of Vit B12 from Haptocorrin, and while in a more neutral pH the B12 will bind …, needed for its absorption.
Intrinsic Factor
What secretes Intrinsic Factor?
Parietal Cells
A Vit. B12 deficiency produces …
Pernicious Anemia
What is Pernicious Anemia usually associated with?
Achlorhydria, and/or lack of Parietal Cells
What can mucus cells utilize to maintain a buffering barrier that is actually alkaline?
dead mucosal cells, and HCO3- from the Alkaline Tide produced by the Parietal Cells
How does H. Pylori contribute to its own protection from acid and Pepsin?
By producing the enzyme Urease that converts Urea into Ammonia and Bicarb (promotes replication and growth)
H. Pylori is the most common cause of what?
Peptic Ulcers
What percent of the total response to a meal does the Cephalic Phase have on gastric acid secretion?
30%
What percent of the total response to a meal does the Gastric Phase have on gastric acid secretion?
60%
What percent of the total response to a meal does the Intestinal Phase have on gastric acid secretion?
10%
