Intro to GI Physiology

Question 1

allow organs to function in syncytium

Answer 1

gap junctions

Question 2

what is pharmacomechanical coupling

Answer 2

found in smooth muslce, ligand activation, activation of G protein, release Ca from intracellelar storage

Question 3

what do Ca channel blockers do

Answer 3

disrupt GI motility by preventing rapid inward current depolarization

Question 4

what causes depolarization of RMP in ENS

Answer 4

stretching, Ach, hormones

Question 5

what causes hyperpolarization in RMP of ENS

Answer 5

sympathetic

Question 6

what is effect of sympathetic innervation of GI

Answer 6

reduce blood flow, motility, and secretion

Question 7

what is the main mediator of sympatheric innervation

Answer 7

NE

Question 8

NE acts directly on

Answer 8

smooth muscle sphincter

Question 9

reflexes from gut to paravertebral ganglia and back to gut

Answer 9

gastrocolic, enterogastric, colonoileal

Question 10

reflexes from gut to spinal cord or brainstem and back to the gut

Answer 10

vagovagal, pain, defecation

Question 11

controls contraction in GI muscle layers in response to food stimuli

Answer 11

vagovagal

Question 12

T/F efferents that synapse with musculature are both inhibitory and stimulatory

Answer 12

T

Question 13

T/F efferents that synapse with secretory are both inhibitory and stimulatory

Answer 13

False, only excitatory

Question 14

motor, between longitudinal and circular

Answer 14

myenteric (auerbach’s plexus)

Question 15

secretomotor, absent in esophagus

Answer 15

submucosal, meissner plexus

Question 16

controls motility, contains excitatory and inhibtiory

Answer 16

myenteric

Question 17

controls local secretion and absorption

Answer 17

submucosal

Question 18

type of nuerons that is largests portion of auerback

Answer 18

AH

Question 19

nueron that has nicotinic fast EPSP, greater excitability, resonds to tetradoxin (NA channel blocker)

Answer 19

S type

Question 20

what is the second messenger of AH type cells

Answer 20

cAMP

Question 21

what is the second messenger of S type cells

Answer 21

IP3 and Ca2+

Question 22

what neurotransmitters evoke EPSP

Answer 22

Histamine, serotonin, substance P, Gastrin, CCK and ACh

Question 23

Fast EPSP is mediated by ______ and couples with

Answer 23

ACh; ion channels

Question 24

what are the slow IPSP

Answer 24

opioid, NE, galanin, adenosine

Question 25

NE acts on what receptors

Answer 25

A2 adrenoreceptors, mimicked by somatostatin in meissners plexus

Question 26

where does galanin work

Answer 26

auerbach

Question 27

adenosine acts through what receptors

Answer 27

A1, low cAMP

Question 28

what are the mediators of prsynaptic inhibition

Answer 28

CCK, ATP, histamine, NE, and ACH

Question 29

_______ surpresses fast and slow EPSPs in myenteric plexus

Answer 29

serotonin

Question 30

______ acts on muscarinic receptors to suppress its own release

Answer 30

ACh

Question 31

main excitatory nuerotransmitters from the musclomotor

Answer 31

Ach and substance P

Question 32

excitatorty secretomotor neurons release primarily

Answer 32

ACh and VIP

Question 33

inhibitory nuerotransmitters

Answer 33

ATP, VIP, NO-inhibit circular

Question 34

why is gastrin not affected by removal of the vagal nerve

Answer 34

itulizes GRP, not Ach

Question 35

tip of villi are

Answer 35

hypoxic