Phys GI motility

Question 1

Connections between smooth muscle cells

Answer 1

nexus. means propagation without nerves

Question 2

nature of chewing

Answer 2

stretch reflex

Question 3

UES vs LES

Answer 3

UES is an anatomical sphincter

LES is not

Question 4

Pressures in esophagus during swallowing

5 items

Answer 4

above 0 at UES, dropping, then rising in swallow
above 0 high up, including neck
below 0 in thorax, positive during swallowing
above 0 at & below diaphragm
above 0 at LES, lowers upon swallowing for entry

Question 5

primary peristaltic wave

Answer 5

swallowing

Question 6

secondary peristaltic wave

Answer 6

sth stuck in throate

Question 7

distribution of muscle fiber types in esophagus

Answer 7

upper 1/3 striated
middle 1/3 transition (both)
lower 1/3 smooth (unaffected by vagotomy)

Question 8

myogenic tone of sphincters

Answer 8

closed. NO from stimulus relaxes

Question 9

location of oxyntic glands

Answer 9

stomach body

Question 10

location of antrum

Answer 10

bottom by pylorus

Question 11

pressure of stomach during swallow

Answer 11

drops to allow entry of food

Question 12

gastric motility

Answer 12

wave goes down to pylorus increasing intensity, maintaining frequency

Question 13

movement of food in stomach

Answer 13

most is squished back up (retropulsion)

very little pushed through pylorus

Question 14

Need spikes for stomach contraction wave?

Answer 14

no, determined by height of plateau. spikes increase intensity

Question 15

frequency of stomach contraction

Answer 15

3-5/min

Question 16

3 things that reduce gastric emptying?

Answer 16

fat
acid
hyper/hypotonic solution

Question 17

fastest emptying thing from stomach

Answer 17

isotonic water

Question 18

SI motor pattern

Answer 18

irregularly spaced waves for stegmental mixing. no propagation

Question 19

actions of SI

Answer 19

mixing
digestion
absorption

Question 20

migrating motor complex

Answer 20

every 90 min in unfed SI (“housekeeper reflex”)

initiated by motolin (from neurons)

Question 21

effect of motolin

Answer 21

migrating motor complex

Question 22

source of electrical stimulus in gut

Answer 22

interstitial cells of Cajal

Question 23

trigger of contraction in stomach and SI

Answer 23

Stomach: waves
SI: needs action potential - spiking on top of slow wave. frequency can approach slow waves, but not exceed it. not propagated.

Question 24

colon features

Answer 24

haustra (bubbles)
teniae coli (longitudinal muscle bands)

Question 25

Ileocecal sphincter actions

control center

Answer 25

relaxation upon ileal distension
contraction on colonic distention
tonic resting contraction

controlled in the wall of the gut

Question 26

mass movement

Answer 26

haustrations disappear in colon, sht moves, several times a day.

Question 27

achalasia

Answer 27

failure to relax esophageal sphincter

Question 28

megacolon

Answer 28

failure to relax rectal sphincter (absence of ganglion?)