Block 3 - General - Quiz, Flashcards & Trivia

1. What are examples of postganglionic parasympathetic nerves throughout the GI tract that do not release ACh?

- release of NO yields relaxation of lower esophageal sphincter, corpus cavernosum
- release of GRP yields G cells /stomach to release gastrin
(NANC)

Release of epinephrine causes inhibition of peristalsis in the intestines

Activation of beta-adrenergic receptors results in decreased secretion of bile from the gallbladder

Release of dopamine leads to increased secretion of bicarbonate in the pancreas

2. What is the class, origin, primary regulation of secretion, and primary functions of Gastrin?

Antibody

Enzyme

Neurotransmitter

Hormone
Origin of secretion: primarily G-cells in antrum of stomach
Primary regulation of secretion:
Stimuli: proteins; distention; vagal post-ganglionic fibers (gastrin releasing peptide); enteric nerves
Inhibitors: low pH in stomach; somatostatin from D cells in antrum of stomach
Primary functions:
• Stomach: directly stimulates parietal cell HCl
secretion, stomach wall motility, stomach mucosal
growth

Gastrin is a hormone primarily secreted by G-cells in the antrum of the stomach. Its secretion is primarily regulated by stimuli such as proteins, distention, vagal post-ganglionic fibers, and enteric nerves. Gastrin functions include stimulating parietal cell HCl secretion, stomach wall motility, and stomach mucosal growth.

Explanation

Gastrin is a hormone primarily secreted by G-cells in the antrum of the stomach. Its secretion is primarily regulated by stimuli such as proteins, distention, vagal post-ganglionic fibers, and enteric nerves. Gastrin functions include stimulating parietal cell HCl secretion, stomach wall motility, and stomach mucosal growth.

3. What is the primary function of secretin in the body?

Inhibits gastrin-induced HCl secretion from parietal cells

Inhibits the release of insulin from the pancreas

Stimulates bile production in the liver

Hormone
Origin of secretion: S cells of the duodenum of small
intestine
Primary regulation of secretion:
Stimuli: low pH in the duodenum of the small intestine
Primary functions:
• Stomach: inhibits G cells of the stomach, which
inhibits gastrin-induced HCl secretion from parietal cells
• Pancreas (exocrine): stimulates bicarbonate
secretion; stimulates growth
• Liver: stimulates bicarbonate secretion into the biliary
system

Secretin primarily stimulates bicarbonate secretion in the pancreas and liver, as well as promoting growth.

Explanation

Secretin primarily stimulates bicarbonate secretion in the pancreas and liver, as well as promoting growth.

4. What is the function of Glucose-dependent Insulinotropic Peptide / Gastric Inhibitory Peptide (GIP)?

Antibody

Enzyme

Neurotransmitter

Hormone
Origin of secretion: K cells in the duodenum and jejunum of small intestine
Primary regulation of secretion:
Stimuli: protein, fat, carbohydrate in the duodenum and jejunum of small intestine
Primary functions:
• Stomach: inhibits parietal cell HCl secretion
• Pancreas (endocrine): stimulates insulin secretion

GIP is a hormone secreted by K cells in the duodenum and jejunum of the small intestine. Its primary functions include inhibiting parietal cell HCl secretion in the stomach and stimulating insulin secretion in the pancreas.

Explanation

GIP is a hormone secreted by K cells in the duodenum and jejunum of the small intestine. Its primary functions include inhibiting parietal cell HCl secretion in the stomach and stimulating insulin secretion in the pancreas.

5. What is the primary function of Motilin?

Antibody

Neurotransmitter

Digestive enzyme

Hormone
Origin of secretion: endocrine cells in the duodenum and jejunum of small intestine
Primary regulation of secretion:
Stimulus: neural inputs (ACh) during fasting
Primary functions:
• Stomach: stimulates motility*
• Small intestine: stimulates motilility*
* activates interdigestive migrating myoelectric complex

6. What is the primary function of Ghrelin?

Enzyme

Neurotransmitter

Vitamin

Horomone
Origin of secretion: primarily P/D1 cells in the stomach; some cells are also in the small intestine
Primary regulation of secretion:
Stimulus: fasting
Inhibitor: feeding
Primary functions:
• Stomach: stimulates parietal cell HCl secretion,
gastric emptying, and motility
• Brain/behavior: stimulates appetite center in
hypothalamus leading to food intake
• Pituitary: stimulates growth hormone secretion

Ghrelin is a hormone primarily secreted by P/D1 cells in the stomach and small intestine. Its main functions include stimulating appetite, gastric acid secretion, gastric emptying, and growth hormone secretion.

Explanation

Ghrelin is a hormone primarily secreted by P/D1 cells in the stomach and small intestine. Its main functions include stimulating appetite, gastric acid secretion, gastric emptying, and growth hormone secretion.

7. What is the primary role of Somatostatin in gastrointestinal function?

Enhancement of pancreatic enzyme secretion

Promotion of gallbladder contraction

Paracrine regulation of GI function
Origin of secretion: D cells in the antrum of the stomach (paracrine); enteric nervous system interneurons (neurocrine)
Primary regulation of secretion:
Stimulus: low pH in the stomach
Primary GI functions:
Paracrine:
• Stomach: inhibits G cells to inhibit gastrin-induced HCl secretion from parietal cells; directly inhibits parietal cell HCl
secretion; inhibits pepsinogen secretion; inhibits gastric emptying
Neurocrine:
• Small intestine: inhibits motility
• Exocrine pancreas: inhibits zymogen (inactive enzyme) secretions
• Gallbladder: inhibits contraction

Stimulation of acid secretion in the stomach