The Basics

Question 0

Submucosal plexus controls and is located in

Answer 0

secretions, circulation, muscularis mucosae contraction
mixing motion of contraction
submucosa

Question 1

enteric NS is made of what 2 plexuses?

Answer 1

Submucosal

myenteric

Question 2

myenteric plexus is located where and controls what

Answer 2

between muscle layers

controls motility

Question 3

Ach

Answer 3

increases activity of enteric NS

also used by ANS

Question 4

VIP

Answer 4

increases secretion
decreases motility
vasodilates

Question 5

Norepi

Answer 5

decreases avtivity, especially motilit

also used by extrinsic ANS

Question 6

NItric oxide

Answer 6

major inhibitory NT of enteric

required to cause relaxation

Question 7

DZ ass’d with NO

Answer 7

Hirschbrungs= restriction tightly contracted. obstruction
Aclasia= LES doesnt relax, swallowing painful. AI prolem

Question 8

Endorphins action

Answer 8

action to decrease peristalsis
increase mixing motions
net effect= slow down and absorb more H20
when given opiods for pain releif, constipation is a frequent occurence

Question 9

Sympathetic effects in GI

Answer 9

Sympathetic has effects on enteric
decreases activity of intrinisc neurons
decreases GI functions
Decreases BF (which will cause a decrease in secretions)
decrease motility
increases sphincter tone

Question 10

Parasympathetic effects on GI

Answer 10

increase activity of intrinisc neurons
increase most GI functions
increase BF
increase secretion
increase motility
relaxation of sphincters

Question 11

Local reflexes in the gut

Answer 11

distension in stomach increases gastric motility
clear out the distention
moves stuff on into the small intestine
neurons located entirely in enteric NS
no involvement of CNS or ANS

Question 12

Long loop reflexes

Answer 12

distention in stomach
relaxation in colon
“get ready here comes food”
afferent to sympathetic ganglia, then back to gut.
something in one area of GI causes an effect that will be somewhere else in the GI. via sympathetic chain

Question 13

Longest reflexes in GI

Answer 13

cell body in dorsal root ganglinon (not enteric)
to CNS 
back to gut
ie= response to pain. 
created when another sytem gets involved

Question 14

Gastrin - function

Answer 14

increases motility
increases acid secretion
increases pancreatic enzyme secretion

Question 15

Gastrin - released by

Answer 15

G cells in pyloric glands in response to distension

Question 16

Secretin - released by

Answer 16

S cells of intestine, in response to acid in the duodenum

Question 17

Secretin - function

Answer 17

MAIN FXN= protection against acid
stomach - decrease gastrin, decrease acid, decrease motility, increase enzymes
pancreas - increase bicarb, increase enzyme
liver - increase bicarb

Question 18

CCK-PZ - released from

Answer 18

I cells of intestine, in response to fats in duodenum

Question 19

CCK-PZ - function

Answer 19

MAIN ROLE - increase enzyme secretion from pancreas, deal w/fats
pancreas - increase enzyme secretion (pancreozymin)
Gall bladder - contraction of the gallbladder, relax sphincter of oddi
Brain, liver - satiety

Question 20

GLP-1 - released from

Answer 20

L cells, in response to nutrieents, particularly fats and fiber in the intestine

Question 21

GLP-1 - function

Answer 21

Pancreas - increase insulin secretion
stomach - decrease gastric acid, decrease motility

these are activated later in the intestine

Question 22

GLP - 2 - released from

Answer 22

L cells of intestine
in response to nutrients, primarily fats and dietary fiber,
ALSO INTESTINAL INJURY

Question 23

GLP-2 - function

Answer 23

trophic factor for intestine

growth of villi, mucosal, hyperplasia

Question 24

Motilin - released from

Answer 24

stomach, SI, colon
stimulus unknown.
increases every 100 minutes btwn meals

Question 25

Motilin function

Answer 25

excitatory to GI motility, particulary the occurence of the

MIGRATING MOTOR COMPLEX

Question 26

ANS control of GI BF

Answer 26

sympathetic - vasoconstriction, may totally occlude

parasympathetic - dilation

Question 27

Describe counter current BF in villus

Answer 27

due to the counter current of BF, O2 from artery diffuses across to venous blood down concentration gradient,
the tip of the villus is hypoxic ALL the time
bc of hypoxia, cells at tip of villus have a short life span and are routinely shed from villus into lumen

Question 28

P glycoprotein - What is it?

Answer 28

MDR-1 gene product
multi drug resistant
protein survived drug doses that were fatal to other cells

Question 29

P-glycoprotein - What does it do?

Answer 29

remove drugs/ other exogenous substances from cell lumen (prevent absorption). substrate comes into cell, and Pglycoprotein sees it and kicks it back out into the lumen.
Think about this when given drugs, taking in new things.
if given 50mg penicilin orally, might only take in 10 mg.

Question 30

P-glycoprotein - Why study?

Answer 30

influence on drug absorption and therefore effect on efficacy of drug. less p-glycoprotein expression –> more drugs in plasma and vice versa.
polymophisms also suggested in susceptibility to inflammatory bowel dz and colon cancer.
possible that toxins made by intestinal flora are normally extruded from intestinal cells by p-glycoproteiin. in humans, a region on chromosome 7 has been linked to susceptibiltity to IBD and colon cancer.