All of the following statements regarding small intestinal motility are true except?
A. Completely independent of stomach motilityB. CCK increases small intestinal motility
C. Abdominal distension increases motility
D. Increased motility by acetylcholine
Answer.
A. Completely independent of stomach motilityv
Increase in the gastric motility
increases intestinal motility. Though the process is not well understood but
there are some cells in the smooth muscle of GI mucosa K.a. intestinal cell of cajal which generate
basic electrical rhythm (BER) and act as a pacemaker and regulate the motility.
These BERs rarely cause muscle
contraction but spike potential superimposed on the most depolarizing portion
increases muscle tension. Acetyl choline increase the no. of spikes and tension
developed in smooth muscles hence increases motility.
Rate of BER
is:
1. 4/min in stomach
2. 12/min in
duodenum
3. 8/min in distal ileum
4. 9/ min in caecum
5. 16/min in sigmoid colon
