GI Motility Flashcards

1
Q

the trade off for the efficiency of smooth vs. skeletal muscle is

A

speed of contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what part of GI does phasic contractions

A

antral stomach
SI
large intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what part of GI does tonic contractions

A

sphincters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is tonus

A

maintained state of partial contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what does BER stand for

A

basic electric rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

oscillating membrane potential is called

A

slow waves or BER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is another name for BER

A

slow waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does BER do

A

sets pace for contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

slow waves are initiated by

A

pacemaker cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the name of the pacemaker cell of GI

A

Interstitial cells of Cajal (ICC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does ICC stand for

A

Interstitial cells of Cajal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how many waves per min for stomach

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how many waves per min for SI

A

11-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how many waves per min for large intestine

A

2-13

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

hormones can change what regarding contractions

A

amplitude but not frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

if there is no extrinsic innervation, GI muscles contract in response to

A

stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

electrical slow waves in SI are always

A

present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

even without AP, smooth muscle is not completely relaxed in SI, it exhibits

A

tonic contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

if there is action potential on top of slow waves, what happens

A

phasic contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

the greater the number of AP on top of slow wave, the

A

larger the phasic contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe twitches of smooth muscle compared to skeletal

A

in smooth there are not separate twitches, the twitches summate to one long contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

AP are generated in response to

A

neural stimulation
hormonal stimulation
stretching the muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does Ach do to GI

A

increase strength of contraction by increasing Ca2+ in cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how does Ach increase strength of contraction

A

by increasing Ca2+ in cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what does NE do to GI

A

inhibits contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

where are ICC found

A

stomach
proximal duodenum
mid colon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what set the rate of BER

A

ICC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

how do ICC set rate of BER

A

gap junction coupling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are the two motility patterns the enteric NS encodes

A

segmental & peristaltic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

when is the segmental pattern dominant

A

after eating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what does post-prandial mean

A

after a meal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

when is the peristaltic pattern dominant

A

fasting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what part of GI does central nervous system have total control

A

proximal esophagus & anus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what part of GI does central nervous system have partial control

A

distal esophagus, stomach, and colon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what part of GI does central nervous system have almost no control

A

SI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is the major mode of unidirectional propulsion

A

peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what contraction type promotes mixing and can limit transit

A

segmental (rhythmic) contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what is another name for segmental contraction

A

rhythmic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what kind of contractions block transit

A

tonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

draw out the sphicnters

A

pg 12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

how are sphincters contracted

A

tonically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

describe control of swallowing

A

initially voluntary but becomes involuntary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what are the three phases involved in swallowing

A

oral
pharyngeal
esophageal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

describe the oral phase

A

initiated voluntarily by the movement of food to the back of the mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

describe the pharyngeal phase

A

reflexive and peristaltic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

describe the esophageal phase

A

slower and peristaltic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what coordinates the involuntary swallowing process

A

swallowing center in medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

what kind of receptors are in swallowing center

A

Somatosensory receptors in the pharynx stimulate the swallowing center in the medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what is inhibited in pharyngeal phase

A

breathing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what covers larynx opening in pharyngeal phase

A

Epiglottis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

what is purpose of epiglottis covering larynx

A

prevents food from going into trachea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

in esophageal phase, bolus is moved down esophageus by

A

perimary peristaltic wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

if primary peristaltic wave does not clear esophagus, what happens

A

secondary peristaltic wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what controls esophageal phase

A

partly reflexive and partly ENS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

1 second of stimulation for initiation of swallowing leads to

A

9 seconds of programmed muscle contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

list the steps of esophagus reflex

A

pg 15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

when a person isn’t swallowing what is happening with esophageal sphincter

A

contracted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

when a person isn’t swallowing what is happening with glottis

A

open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

when person isn’t swallowing what is happening with epiglottis

A

up

60
Q

when is swallowing reflex triggered

A

when bolus of food reaches the pharynx

61
Q

how does body prevent food from entering trachea

A

larynx moves up and tips epiglottis over glottis

62
Q

calcium activated potassium channel will produce

A

repolarization

63
Q

what kind of receptors in back of throat

A

tactile receptors

64
Q

draw out the vagus nerve and it’s innervation in the esophageal phase

A

pg 18

65
Q

what is the only esophageal motility pattern

A

peristalsis

66
Q

does esophageal muscle have spontaneous contraction

A

no

67
Q

draw out the peristalsis of esophageal in regards to what is relaxing and what is contracting as a bolus travels

A

pg 19

68
Q

draw out the peristalsis mechanism, specifically with the inhibitory interneuron and the excitatory interneuron

A

pg 20

69
Q

what is the purpose of swallowing manometry

A

can see if peristalsis is behaving correctly

70
Q

how is the LES different from the UES?

A

LES has thick band of muscle and will form vestibule (pocket) so acid doesn’t leak out

71
Q

LES is innervated by

A

vagal excitatory fibers

vagal inhibitory fibers

72
Q

relaxation of LES is associated with what happening in its innervation

A

increased frequency of AP for vagal inhibitory fibers

decreased frequency of AP for vagal excitatory fibers

73
Q

what portion of stomach must relax to accept food bolus

A

orad

74
Q

what are the three anatomic regions of the stomach

A

fundus
body
antrum

75
Q

what does fundus do during feeding

A

relaxes

76
Q

the fundus relaxes during feeding, this is called

A

receptive relaxation/accomodation

77
Q

what is the orad portion of the stomach

A

thin walled, receives food bolus through receptive relaxation

78
Q

the stomach can accomodate large volumes without change in

A

pressure

79
Q

receptive relxation is what kind of reflex

A

vagovagal

80
Q

vagovagal reflex in stomach is elicited by

A

stretching of the stomach

81
Q

what does CCK do to the orad area

A

makes it more distendible

82
Q

what is the caudad portion of the stomach

A

thick walled, produces contractions

83
Q

where does contraction begin in the stomach

A

middle of body through caudad

84
Q

what is Retropulsion

A

Not all chyme goes into duodenum as contractions also close pylorus propelling contents back into stomach for further mixing and reduction

85
Q

what is function of pyloric sphincter

A

sieves material, prevents particles that are too big (more than 1 mm) from leaving stomach
prevents reflux of duodenal material

86
Q

what 2 major factors slow or inhibit gastric emptying

A

Fat & H+ in duodenum

87
Q

effects of fat is mediated by

A

CCK

88
Q

if there is too much H+ in stomach what happens

A

deteced by ENS
slows gastric smooth muscle
permits more time for HCO3- to neutralize

89
Q

before a solid meal can be emptied from the stomach, there is what phase

A

lag phase

90
Q

what is the lag phase

A

allows time for the food to be reduced to small enough size to enter SI

91
Q

PNS increases contraction of SI through what 4 neuropeptides

A

ACh, Substance P, enkephalins, motilin

92
Q

what are the two patterns of contraction in the SI

A

segmentation & peristaltic

93
Q

what is quiescent contraction

A

no contraction

94
Q

what are the phases of fasting motility pattern

A

I: quiescent
II: random contractions
III: migrating myoelectric complex

95
Q

what does MMC stand for

A

migrating myoelectric complex

96
Q

phase III/MMC is correlated with rise in levels of what hormone

A

motilin

97
Q

how long does it take MMC to move down SI

A

90 min

98
Q

what is the fed motility pattern

A

irregular spikes from meals → segmental contractions mixed with short perstalic waves

99
Q

what is the function of segmented contraction

A

mixes food and exposes it to all the “juices”

100
Q

what happens when intestines contract in segmented contraction in SI

A

bolus of food is split in orad and caudad directions

101
Q

what happens when intestins relax in segmented contraction in SI

A

the split bolus merges back together

102
Q

what is the function of peristalic contraction in SI

A

propels chyme along SI to LI

103
Q

what neurotransmitters are involved in orad contraction

A

ACh & Substance P

104
Q

what neurotransmitters are involved in caudad relxation

A

VIP

NO

105
Q

peristalic reflex of SI depends on what nervous system

A

enteric

106
Q

intestinointestinal reflex depends on what nervous system

A

extrinsic

107
Q

what is purpose of Intestinointestinal reflex

A

Severe distention in one area inhibits contractions in the remaining bowel.

108
Q

describe the peristaltic reflex in SI

A

Distention of the SI causes contraction above and relaxation below distension.

109
Q

describe the Gastroileal reflex in SI

A

Movement of ileal contents into large intestine is stimulated by the presence of food in the stomach

110
Q

emesis =

A

vomitting

111
Q

prlonged vomitting can result in

A

alkalosis, hypokalemia, and dehydration.

112
Q

retching =

A

dry heaving

113
Q

in dry heaving, what happens regarding UES & LES

A

LES open

UES closed

114
Q

what are the main anatomical regions of LI

A

ascending, transverse, descending, sigmoid colon and the rectum

115
Q

what kind of contractions occur in cecum and proximal colon of LI

A

segmentation contractions

116
Q

movements in colon are coordinated by

A

BER

117
Q

describe segmented contraction in LI

A

occur in cecum and proximal colon: mixes contents; are associated with sac-like segments called haustra. Fibers in external muscle layer form outpouchings.

118
Q

the colon is divided into segments called

A

haustra

119
Q

b/w haustral pockets there are

A

segments of contracted circular muscle

120
Q

what do inhibitory neurons do regarding haustra

A

they maintain the relxation in the haustra/pockets

121
Q

segmented contractions in LI facilitate

A

absorption

122
Q

describe the Colonocolonic reflex

A

Distention of one part of the colon elicits reflex relaxation in other parts of the colon → partly mediated by the sympathetic fibers

123
Q

describe the Gastrocolic reflex

A

The motility of proximal and distal colon and the frequency of mass movements increase after a meal enters the stomach.

124
Q

colonocolic reflex is mediated by

A

sympathetic fibers

125
Q

the gastrocolic reflex is mediated by

A

CCK & gastrin

126
Q

Rectosphincteric reflex is also called

A

defecation reflex

127
Q

describe the Rectosphincteric reflex

A

As rectum fills with feces, smooth muscle wall contracts in the rectum and internal anal sphincter relaxes – no defecation as external anal sphincter tonically contracted

128
Q

when do you get the urge to defecate

A

when the rectum is filled to 25% of its capacity

129
Q

what does the Valsalva maneuver do

A

increase intra-abdominal pressure

130
Q

what does CCK do to gastric emptyin

A

inhibits

131
Q

describe the defecation reflex

A

pg 41

132
Q

during mass movement of colon what happens

A

segmentation stops and haustra disappear, peristaltic contractions move material from one section to another

133
Q

why does H+ slow down gastric emptying

A

too much hydrogen means digestive enzymes wont work need bicarb.

134
Q

compare gastric emptying depending on composition of meal

A

solid goes much slower than semisolid which goes slower than liquid

135
Q

after 60 min how much of solid meal is still in stomach

A

60%

136
Q

if there is semisolid meal how much is still in stomach after 60 min

A

40%

137
Q

if there is liquid meal how much is in stomach after 60 min

A

10%

138
Q

what is lag phase?

A

secretions

mechanical breakdown

139
Q

is there lag phase for liquid

A

no

140
Q

MMC starts where

A

antrum of stomach

141
Q

MMC cycle is how long

A

90 min

142
Q

what is major pattern after meal

A

rhythmic segmentation

143
Q

how does segmentation contraction work

A

contract right in the middle of the food bolus until its small enough to move forward

144
Q

contracting in peristaltic contraction via

A

Ach

Substace P

145
Q

relaxing in peristaltic contraction via

A

VIP

NO