Ingestion/Motility

Question 1

name the general functions of the GI tract

Answer 1

1. ingestion/motility
2. digestion/secretion
3. absorption
4. regulation of GI function

Question 2

movement of food throughout the system is controlled by the ____

Answer 2

intrinsic enteric nervous system

Question 3

within the tract, there are pacemaker cells known as ____

Answer 3

interstitial cells of Cajal

Question 4

AP of interstitial cells of Cajal is the same as the…

Answer 4

SA/AV node of the heart

Question 5

slow waves in an AP are known as…

Answer 5

drifting resting membrane potential

Question 6

action potential in the intrinsic enteric nervous system is called ____

Answer 6

spike potential

Question 7

what occurs during the rising phase?

Answer 7

Ca in

Question 8

what occurs during the falling phase?

Answer 8

K out

Question 9

what effect does the number of spike potentials have on contraction?

Answer 9

larger number of spike potentials -> stronger contraction

Question 10

what increases peristalsis?

Answer 10

parasympathetic (Ach)

Question 11

what decreases peristalsis?

Answer 11

sympathetic (NE/E)

Question 12

activation of the ____ is associated with contraction of smooth muscle in the GI tract

Answer 12

Myenteric plexus (Auerbach’s Plexus)

Question 13

the extrinsic nervous system innervates the ____

Answer 13

Myenteric Plexus (Auerbach’s Plexus)

Question 14

name the 4 types of contraction by the Auerbach’s plexus

Answer 14

1. tonic contractions
2. giant migrating complexes
3. migratory motor complexes (MMCs)
4. mixing contractions

Question 15

there is always ____ due to the parasympathetic nervous system always being on at 50%

Answer 15

tone

Question 16

what increases tone?

Answer 16

parasympathetic (Ach)

Question 17

what are the parasympathetic innervations that affect tone?

Answer 17

• vagus (CN X) from esophagus to splenic flexure of LI
• S2, S3, S4: descending colon to anus

Question 18

what is responsible for decreased tone?

Answer 18

sympathetic (NE/E)

Question 19

giant migrating complexes (mass movements) are increased by ____

Answer 19

serotonin

Question 20

what is the function of giant migrating complexes?

Answer 20

allows contractions over long distances as required for bowel movement

Question 21

migratory motor complexes are increased by ____

Answer 21

motilin

Question 22

function of migratory motor complexes

Answer 22

housekeeping function: keeps moving contents toward the colon

Question 23

where do mixing contractions primarily occur?

Answer 23

stomach

Question 24

name 3 examples of reflexes

Answer 24

1. gastrocolic (stomach -> colon)
2. enterogastric
3. colonoileal

Question 25

if gastrocolic reflexes are going “forward,” what happens to the rate of contractions?

Answer 25

increases

Question 26

if gastrocolic reflexes are going “backward,” what happens to the rate of contractions?

Answer 26

slows