Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

HUBS192 2022 > lecture 24 - GI motility > Flashcards

lecture 24 - GI motility Flashcards

(90 cards)

Start Studying
1
Q

What are the factors that receptors in the wall of the GI tract respond to?

A

Stretch (via food in the lumen), change in composition - pH, osmolarity, amino acids, sugars, fats

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

What are the effectors of GI regulation?

A

Smooth muscle (contraction), glands (secretion)

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

What are the 2 types of GI regulation?

A

Hormonal and nervous (ENS and CNS)

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

What is the role of the parasympathetic nervous system in GI function?

A

Stimulates motility and secretion

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

What is the role of the sympathetic nervous system in GI function?

A

inhibits motility and secretion

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

How are the CNS and ENS connected?

A

The CNS modulates activity of enteric nervous system

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

What nervous system coordinates GI fucntion over long distances?

A

Central Nervous System

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

What component of the ENS regulates secretion?

A

Submucosal plexus

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

What component of the ENS regulates motility?

A

Myenteric plexus

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

What are the functional differences between the submucosal plexus and myenteric plexus?

A

Submucosal plexus regulates secretion, while the myenteric plexus regulates motility

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

What are the 2 key local motility reflexes of the GI system?

A

Peristalsis and segmentation

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

What are the 2 key functions of the CNS in GI function?

A

Integration of responses to external stimuli (senses, emotions, etc.) and response to internal stimuli, such as GI lumen contents via a long reflex path

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

What neurotransmitter is involved in sympathetic CNS control of the GI tract?

A

Noradrenaline

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

What neurotransmitter is involved in parasympathetic CNS control of the GI tract?

A

acetylcholine

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

What are the key types receptors that feedback to the ENS?

A

Stretch/mechano-, osmo- and chemo- receptors

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

What is the difference between reflex pathways in the ENS and CNS?

A

Short, local pathways in ENS, long pathways to CNS

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

What is the largest endocrine organ in the body?

A

The GI tract

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

What are the 2 types of hormonal regulation in the GI system?

A

Endocrine and paracrine

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

What is endocrine regulation?

A

Regulation by hormones that are secreted into the bloodstream for distant effect

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

What is paracrine regulation?

A

Secretion of hormones to effector cells that are adjacent to the secretory cells

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

What are the 4 critical hormones of GI regulation?

A

Gastrin, Gastric Inhibitory Peptide (GIP), Secretin, Cholecystokinin (CCK)

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

What does the GIP hormone stand for?

A

Gastric Inhibitory Peptide

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

What does the CCK hormone stand for?

A

Cholecystokinin

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

What are the 2 types of contractions in GI motility?

A

Tonic and phasic contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are tonic GI contractions?
Sustained contractions for minutes to hours
26
What feature of the GI system often employ tonic contractions?
Sphincters - they are sustained shut/open for a long time
27
What are GI phasic contractions?
Waves of contraction and relaxation over seconds
28
What type of contraction is in peristalsis?
Phasic contractions
29
What is a motility pattern in the GI tract?
Any pattern of contraction or relaxation of GI tract smooth muscle
30
What is an example of relaxation being a GI motility pattern?
Storage in the stomach
31
What are movement/propulsion in terms of motility patterns?
Motility patterns that specifically move or propel GI contents along the tract.
32
What does it mean when the Gi tract is ‘spontaneously active’?
It contracts without external input
33
What is the frequency of contraction a property of?
The region of the tract
34
What is the frequency of contractions in the stomach?
3 per minute
35
What is the frequency of contractions in the duodenum?
12 per minute
36
What is the frequency of contractions in the ileum?
9 per minute
37
What is the strength of GI contractions regulated by?
Nervous and hormonal input
38
What is the motility pattern during the fasting state?
Migrating Motor Complex (MMC)
39
When is the Migrating Motor Complex employed?
During the fasting state
40
When does the Migrating Motor Complex begin?
4 hours after a meal
41
How often does the migrating motor complex repeat?
Every 2 hours until food is eaten again
42
What is the purpose of smooth muscle relaxation during the feeding state?
Allows the volume of the tract to increase without a change in pressure
43
Where does storage occur during the feeding state?
Stomach and colon
44
What is the motility pattern that occurs for propulsion/movement during feeding?
Peristalsis
45
What are the key steps in peristalsis?
Bolus of food arrives, circular muscles contract behind it, longitudinal muscles ahead of bolus contract, circular muscle contracts to force bolus forward
46
What muscles contract first in peristalsis?
Inner Circular muscles behind the bolus
47
What muscles contract second in peristalsis?
Longitudinal muscles ahead of the bolus
48
What is the segmentation motility pattern?
Intermittent ‘pinching’ of tract to mix chyme back and forth too expose it to absorbant surfaces
49
Is chewing conscious or voluntary?
Both - has voluntary skeletal muscle control but also reflex control of strength, frequency and rhythm
50
What is the purpose of chewing?
Allows ingestion by reducing the size of food. Mixes food with saliva to start digestion and allow for taste.
51
Is swallowing reflexive of voluntary?
Initiated at will, but proceeds reflexively.
52
What is the purpose of swallowing?
The rapid transfer of material from mouth to stomach
53
What are the 3 phases of chewing/swallowing?
Buccal, pharyngeal, oesophageal
54
What are the 4 functions of gastric/stomach motility?
Storage, mechanical digestion, mixing, controlled delivery to the duodenum
55
What part of the stomach is involved in storage?
Fundus and body - at the top of the stomach
56
What part of the stomach is involved in mechanical digestion and mixing?
Antrum - where there is the greatest amount of muscle
57
What part of the stomach is involved in the motility pattern associated with controlled delivery to the duodenum?
Pyloric sphincter
58
In the migrating motor complex, what is the ratio of uncoordinated and coordinated activity?
50 minutes of uncoordinated activity followed by 10 minutes of coordinated activity
59
What is the primary purpose of the migrating motor complex during the fasting state?
House keeping
60
What are the 3 functions of the migrating motor complex/fasting gastric motility?
Removes residual secretions, removes undigested material, promotes epithelial cell turnover
61
What is the epithelial cell turnover?
Every 5 days all epithelial cells in the stomach are replaced
62
What triggers a reflex for gastric relaxation?
Swallowing
63
What feedback loop causes gastric accomodation?
Stretch reflexes in the stomach tell the brain that the stomach has expanded, triggering a signal for the stomach to expand even further to accomodate.
64
What is the primary nerve involved in nervous regulation of gastric storage?
The vagus nerve
65
What characteristic of the stomach is unchanged, despite the increased volume during storage?
Pressure has minimal change
66
Where is peristalsis initiated in the stomach?
The greater curvature, then spreads to the antrum
67
How do peristalsis contractions in the stomach change over time after a meal?
first 60 minutes after a meal the contractions are gentle, and then get more intense until approx. 300 minutes
68
What motility pattern in used in the stomach to promote mixing and mechanical breakdown?
Retropulsion.
69
What is gastric retropulsion?
Combination of peristalsis and closure of the pyloric sphincter
70
What is the purpose of gastric mixing?
Combines chyme with acid and pepsin to promote digestion
71
What is the rate of gastric emptying dependent on?
The digestive capacity of the intestine
72
What motility patterns aid in gastric emptying?
Combination of peristalsis and periodic opening/relaxation of the pyloric sphincter
73
What feedback regulates gastric emptying?
Feedback from the duodenum
74
What 2 factors affect gastric emptying?
Size/volume of the meal, meal composition
75
What food component slows gastric emptying due to being difficult to digest in the stomach?
Fats
76
Why are fats difficult to digest in te stomach?
Fats require bile salts for emulsification, which are not produced in the stomach
77
What are the characteristics of the chyme that is emptied from the stomach into the duodenum?
Fatty, hypertonic, acidic
78
What is the nervous negative feedback loop that slows the release of chyme into the duodenum?
When chyme enters the duodenum is triggers chemoreceptors and stretch receptors that trigger the enterogastric reflex, which stimulates both enteric neurons (short reflex) and CNS centres (long reflex) to decrease the contractile force of the stomach and slow stomach emptying.
79
What is the endocrine negative feedback loop that slows the release of chyme into the duodenum?
Presence of chyme in duodenum causes duodenal enteroendocrine cells to secrete hormones/enterogastrones to decrease gastric emptying and the contractile force of the stomach
80
What are enterogastrones?
Hormones released by the duodenum in response to fatty chyme, and act to inhibit gastric motility
81
What are the 3 key functions of small intestine motility?
Mix chyme with pancreatic, biliary and intestinal secretions, control movement/propulsion, expose products of digestion to absorptive surfaces
82
What is the main motility pattern in the small intestine between meals?
Migrating motor complex
83
What is the purpose of the migrating motor complex in the small intestine?
Clearing unwanted secretions
84
What is the main motility pattern in the small intestine after a meal?
Segmentation, with some peristalsis
85
What is the function of segmentation in the small intestine after a meal?
Mixing, exposure to absorptive surfaces
86
What are the 2 key motility patterns of the large intestine?
Segmentation and mass movement (propulsion)
87
What is the function of the segmentation motility pattern in the large intestine?
Exposure of faeces to absorptive surfaces for absorption of fluid and salt
88
How often does mass movement from the large intestine occur?
1 to 2 times a day
89
What type of motility pattern is mass movement?
Peristaltic wave
90
What is the fucntion of mass movement in the large intestine?
Drives faeces into the rectum and initiates defecation.

HUBS192 2022 (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions