Gut motility

Question 1

what is the gut wall mainly made up of

Answer 1

smooth muscle (involuntary,non-striated) + interstitial pacemaker cells

Question 2

what is enteric nervous system

Answer 2

The enteric nervous system is the largest and most complex unit of the peripheral nervous system, with ~600 million neurons releasing a multitude of neurotransmitters to facilitate the motor, sensory, absorptive, and secretory functions of the gastrointestinal tract

Question 3

what are the taenia coli?

Answer 3

3 bands of muscles in the colon (large intestine)

Question 4

function of interstitial muscle cells

Answer 4

these interstitial cells of cajal are bundles of cells (syncytia i.e. when one cell depolarises it effects the others) in gut wall which connect together by gap junctions. This depolarisation communicates a rhythm of depolarisation which causes the muscle contractions of gut.

The interstitial pacemaker cells..
· Spontaneously depolarise and connect as a syncytium
· Dominant pacemaker area creates slow waves of electrical activity, passing around and down the stomach
· Creates a pattern of excitation - facilitates or ‘paces’ the ability of the enteric nervous system to stimulate muscle movements
Damaged ICCs disrupt waves of electrical activity: Nausea

Question 5

name the 3 layers of the gut

Answer 5

outer layer of longitudinal muscle

myenteric plexus which is the primary motility controller

inner circular muscle

submucosal plexus which is primary fluid exchange controller

mucosa where the sensory + motor nerve endings are found

Question 6

describe peristalsis

Question 7

describe movement of food in the colon + rectum