Digestive System - General and Motility

Question 1

what are the 4 main functions of the digestive system

Answer 1

1. digestion - chemical and mechanical
2. absorption - active and passive transport of monomers from the lumen into the mucosa
3. secretion - many substances secreted by mucosa
4. motility - movement

Question 2

what are the two main types of contractions and describe them

Answer 2

1. tonic contractions: sustained contractions for minutes to hours (eg. sphincters)
2. phasic contractions: seconds of contraction/relaxation

Question 3

what are the three patterns of motility

Answer 3

1. migrating motor complex - between meals
2. peristalsis - rhythmic smooth muscle contraction
3. segmentation contraction in the middle of the bolus; to mix with secretions