Lecture 32

Question 1

What are the two main functions of the small intestine?

Answer 1

1. To transport chyme to the stomach at a rate that is appropriate for digestion and absorption
2. Mix digesta

Question 2

Describe the process of peristalsis that occurs within the large intestine:

Answer 2

Behind the bolus the longitudinal muscle relaxes and the circular muscle contracts. In front of the bolus the longitudinal muscle contract, and the circular muscle relaxes

Question 3

What occurs in segmentation process?

Answer 3

Random localised contractions of smooth muscle. Small segments contract will other local segments relax allowing for the mixing of digesta

Question 4

What occurs in the inter-digestive phase?

Answer 4

Slow moving contraction that starts in the stomach and moves down every 90-120 minutes. Also called the migrating motor complex. Between them there is a quiet period with no action potentials.

Question 5

How is motility regulated in the digestive system?

Answer 5

The slow wave in mediated by the interstitial cells of Cajal:

Question 6

What are the general functions of the large intestine?

Answer 6

• absorption of electrolytes
• microbial digestion and absorption of carbohydrates and proteins that escaped digestion in the for-stomach and small intestine
• moves digesta aborally, mixing and retaining contents for optimal absorption and fermentation