GI: Secretions of the Gastrointestinal Tract I

Question 1

Describe the structure and functions of the esophagus.

Answer 1

The esophagus doesn’t make enzymes, only mucous. It serves to lubricate and protects the esophagus from digestion by gastric juices. *if you don’t make mucous in your stomach, it digests itself.

Question 2

Describe the function and control of prehension, mastication, salivation, and deglutition.

Answer 2

Saliva lubricates food, forms bolus to swallow, solubilizes dry food, initiates starch digestion (a-amylase/ptyalin), oral hygiene has IgA… oral and nasal vaccines are trying to stimulate IgA.

Question 3

Describe and specify the functions of the different cell types in the gastric epithelium, including mucous neck cells, parietal cells, chief cells and endocrine cells.

Answer 3

Chief cells (peptic cells) secrete pepsinogen and secrete rennin (with TWO Ns!!). Pepsinogen becomes active in the stomach and then digests proteins. Parietal cells secrete HCl and intrinsic factor. parietal cells secrete into the lumen, endocrine secretes into the blood. Mucous neck cells secrete mucous.

Question 4

Describe the control of gastric secretions and the interactions of the stomach with the rest of the digestive tract.

Answer 4

Gastric secretions: HCl, pepsinogen, IF, mucous, rennin. Pyloric: Gastrin, mucous, some pepsinogen.
The most important job of your stomach is making intrinsic factor. It’s also a short term storage. There are two types of glands in your stomach, gastric and pyloric - they are tubular simple glands. B12 is made in the ileum, lack of B-12 results in pernicious anemia.

There are phases of gastric secretion. The cephalic phase, before food enters stomach. The gastric phase, once food enters the stomach, 60% of gastric secretion. & the intestinal phase, 10% of gastric secretion. Gastric secretion is regulated by

Question 5

Describe how the integrity of the gastric epithelium is maintained and mechanisms that lead to its disruption.

Answer 5

The stomach makes mucous, is lined by surface mucous cells. The mucous is alkaline. Contact with food produces more mucous. Gastric juices still made on an empty stomach for protective services.