Physio 1

Question 1

Type of smooth muscle unit that makes up the stomach and intestines.

Answer 1

Unitary

Question 2

Type of smooth muscle that makes up the gall bladder and esophagus.

Answer 2

Multi-unit

Question 3

Cell types with many gap junctions that act as the pacemaker in the GI tract.

Answer 3

Interstitial Cells of Cajal

Question 4

During slow wave potentials in the GI tract muscle layers, what creates the plateau in the action potential?

Answer 4

The opening of Calcium channels creates and inflow of calcium ions that matches the outflow of potassium ions.

Question 5

Do slow waves elicit muscle contraction?

Answer 5

No. Slow waves occur all the time but do not create a strong enough signal to cause muscle contraction. A stimulus, such as stretching the bowel from the presence of food or even just hormones causes an increase in calcium release leading to a “spike” potential. Spike potentials cause contraction

Question 6

Enteric nerve plexus found between the two major muscle layers.

Answer 6

Auerbach Plexus

Question 7

Enteric nerve plexus found deep to the inner circular muscle layer and outside the submucosa.

Answer 7

Meissner Plexus

Question 8

Inhibitory neurotransmitters in the enteric nervous system.

Answer 8

Vasoactive Intestinal Peptide (VIP)
Nitric Oxide (NO)

Question 9

Excitatory neurotransmitters in the enteric nervous system.

Answer 9

ACh

Substance P