Intro

Question 1

defect in lower esophageal sphincter

Answer 1

heartburn/acid indigestion

Question 2

defect in pyloric sphincter

Answer 2

gastritis, ulcer formation, risk of perforation

Question 3

defect in ileocecal sphincter

Answer 3

IBS due to bacterial overgrowth in small intestine

Question 4

how is acidic chyme from stomach neutralized

Answer 4

HCO3- from exocrine pancreas secreted into duodenum

Question 5

ENS afferents are

Answer 5

sensory

Question 6

ENS efferents are

Answer 6

secretomotor

Question 7

sense stretch of smooth muscle; signal goes through myenteric (Auerbach’s) plexus, stimulates contractions

Answer 7

mechanoreceptors in gut

Question 8

sense chemical composition of chyme; regulate motility and secretion of buffers to control luminal pH during influx of acidic chyme into duodenum

Answer 8

chemoreceptors

Question 9

sense osmolarity of chyme in small intestine; control amount of chyme entering SI as well as amount of secretions needed to buffer chyme

Answer 9

osmoreceptors

Question 10

increases gut motility, relaxes sphincters, enhances secretions

Answer 10

parasympathetics

-vagus and pelvic nerves

Question 11

parasympathetic preganglionic fibers (vagus and pelvic nerves) of the ENS terminate on

Answer 11

postganglionic cholinergic or peptidergic neurons located in the plexuses

Question 12

afferent and efferent impulses carried by mixed vagus nerve

Answer 12

vagovagal reflexes

Question 13

innervate distal 1/3 of colon

Answer 13

pelvic nerves - parasym

Question 14

innervates 2/3 of ENS from pharynx to beginning of distal colon

Answer 14

vagus nerve - parasym

Question 15

major sympathetic neurotransmitter of ENS

Answer 15

norepi

Question 16

inhibits excitatory cholinergic neurons via presynaptic inhibition in ENS

Answer 16

norepi

Question 17

inititation of salivation happens during

Answer 17

cephalic phase

Question 18

nerves involved in cephalic phase (salivation)

Answer 18

facial, glossopharyngeal

Question 19

where is the swallowing center

Answer 19

medulla

Question 20

nerve involved in gastric phase, and some of cephalic phase

Answer 20

vagus

Question 21

nervous structures involved in perstalsis

Answer 21

vagus, swallowing center of medulla

Question 22

pacemakers of GI tract; abundant in myenteric plexus

Answer 22

interstitial cells of Cajal

Question 23

contraction of G wall occurs

Answer 23

when APs are generated at peaks of slow waves

Question 24

describe contractions of ICCs

Answer 24

continual, slow intrinsic electrical activity

Question 25

contractions that maintain tone without regular relaxation

Answer 25

tonic contractions

Question 26

where do tonic contractions occur

Answer 26

orad stomach

Question 27

connection between ICCs and circular muscle

Answer 27

gap junctions

Question 28

equivalent to resting membrane potential of the GI smooth muscle

Answer 28

slow waves

Question 29

how does PNS increase strength of contractions in gut

Answer 29

increase number of action potentials

Question 30

modulate productoon of APs and strength of muscle contractions

Answer 30

neural and hormonal input

Question 31

in the small intestine, stretch, Ach, and Parasym stimulate

Answer 31

spikes, depolarization

Question 32

in the small intestine, norepi and sympathetics stimulate

Answer 32

hyperpolarization

Question 33

what kind of contractions does muscarininc choliergic antagonist atropine cause

Answer 33

weak

Question 34

atropine

Answer 34

muscarinic cholinergic antagonist | -stimulates weak contractions in the gut

Question 35

what add to the weak contractions of the gut controlled by atropine

Answer 35

excitation from myenteric nerve plexus

Question 36

gastroenteric reflex

Answer 36

enhanced peristaltic motility and secretions after a meal

Question 37

gastroileal reflex

Answer 37

opens ileocecal valve so chyme can pass from small intestine to large intestine

Question 38

gastroileal reflex: distention of ileum leads to

Answer 38

relaxation of ileocecal sphincter

Question 39

gastroileal reflex: distention of ascending colon leads to

Answer 39

contraction of ileocecal sphincter

Question 40

enterogastric reflex

Answer 40

optimizes digestion and absorption - decreases gastric motility and secretions - contracts pyloric sphincter - inhibits chyme from entering duodenum

Question 41

peristalsis and motility of small intestine are controlled by

Answer 41

myenteric plexus (Auerbach's)

Question 42

aboral

Answer 42

away from mouth

Question 43

orad

Answer 43

toward mouth

Question 44

peristalsis: contractile ring forms on

Answer 44

orad side

Question 45

peristalsis: receptive relaxation occurs

Answer 45

aborally (downstream)

Question 46

peristaltic propulsion: receiving segment

Answer 46

longitudinal contracts | circular relaxes

Question 47

peristaltic propulsion: propulsive segment

Answer 47

circular contracts | longitudinal relaxes

Question 48

Ach and Substance P are (excitatory/inhibitory)

Answer 48

excitatory

Question 49

VIP is (excitatory/inhibitory)

Answer 49

inhibitory

Question 50

causes of pathological ileus

Answer 50

abdominal surgery, anticholinergic drugs, opiates

Question 51

patholoigical ileus

Answer 51

normal periods of quiescence are much longer

Question 52

physiological ileus

Answer 52

absence of motility in intestines - normal

Question 53

acts during fasting, sweeps stomach and SI of undigested food/fiber, prevents overgrowth of bacteria, inhibits pyloric sphincter during this process

Answer 53

Migrating Motor Complex

Question 54

where is Motilin synthesizes

Answer 54

duodenal Mo cells

Question 55

motilin

Answer 55

acts during active phase of MMC

Question 56

bezoars

Answer 56

accumulate in absence of MMC, obstruct lumen of stomach

Question 57

effect of vagotomy on MMC

Answer 57

reduces contractile activity

Question 58

pharyngeal phase of swallowing

Answer 58

- efferent signals from vagus and hypoglossal to swallowing centers in medulla - soft palate moves up - epiglottis covers trachea

Question 59

esophageal phase of swallowing

Answer 59

primary peristaltic wave + receptive relaxation of stomach

Question 60

damage to these CNs can impair swallowing

Answer 60

V, IX, X

Question 61

components of swallowing center in medulla

Answer 61

``` nucleus ambiguus (CN IX, X), dorsal motor nucleus of vagus ```

Question 62

effect of vagotomy on gastric accomodation

Answer 62

reduced - increase in intragastric pressure happens sooner

Question 63

failure of LES to relax during swallowing (no receptive relaxation)

Answer 63

achalasia

Question 64

LES tone is not properly maintained

Answer 64

GERD

Question 65

what factor allows LES to relax

Answer 65

VIP

Question 66

proximal gastric reservoir

Answer 66

fundus, 1/3 of body

Question 67

distral antral pump

Answer 67

caudal 2/3 of body, antrum, pyloris

Question 68

T/F: muscles of gastric reservoir contract phasically

Answer 68

False - constant tone

Question 69

T/F: muscles of antral pump contract phasically

Answer 69

True

Question 70

actions of stomach

Answer 70

propulsion, grinding, retropulsion