L4 Regulation of the GIT Secretion

Question 1

Outline the function of the pancreas and its role in digestion

Answer 1

Enzymes; trypsinogen, chymotrypsinogen, lipase, amylase.

Bicarbonate of a pH 7-8

Stimulated by acetylcholine CCK and secretin

Question 2

Outline the functions of the liver and its role in digestion

Answer 2

Bile produced in the liver and stored in the gallbladder has a pH of 7-8

Stores and released nutrients for fat, carbohydrate and protein metabolism

Extretory route for products of breakdown of red blood cells give colour to bile bilirubin

Stores vitamins and minerals

Detoxifies drugs

Produces blood clotting factors

Endocrine role

Cleansing of blood removing bacteria

Question 3

Discus the concept of regulation in the GIT through endocrine, paracrine and neuronal mechanisms

Answer 3

Cheif cells produce pepsinogen

Paritel cells secrete HCl

Saliva

Amylase enzyme
Bicarbonates maintain a neutral pH as ruminants produce volatile fatty acids and rely on microbes being healthy
Lubrication
Digestion

Question 4

Outline the dynamic and responsive nature of the GIT secretions using cephalic, gastric and intestinal phases of gastric secretion as an example

Answer 4

Cephalic
A conditioned reflex of sight/smell/taste of food. Via vagus causes gastric and histamine secretion. Increase motility. Increase HCL and Pepsinogen.

Gastric
Chemo and mechanoreceptors lead to the release of gastrin and histamine.

Intestinal
The presence of chyme in the duodenum leads to the secretion of secretin, CKK and gastric inhibitory peptide. Inhibit motility, gastrin, pepsin, and HCl.

Question 5

What does the small intestinal epithelium secrete

Answer 5

Succus entericus
lactase, maltase, lipade ph7-8

Alkaline mucoid fluid from Brunner’s glands