Flashcards in Trans - Gastric Motility Deck (78)
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0
Which of the ff is not a function of the GI System?
a. facilitate speech
b regulate blood components
c. digest food and absorb nutrients
d. NOTA
b.
d. NOTA
1
Which structure is mismatched with their description?
a. stomach - initial digestion of proteins
b. UES - Cricopharyngeus
c. LES - Circular Muscle thickening
d. Pylorus - Oblique Muscle thickening
D
2
What layer is responsible for propulsion of bolus?
Muscularis Externa
3
Which muscle layer is most affected by hypotension?
Mucosa
4
Which layer is most susceptible to necrosis?
Mucosa; because it is farthest from vasculature
5
Part of enteric nervous system found in submucosa?
Meissner's plexus
6
Part of enteric nervous system found between circular and longitudinal muscle layers
Auerbach's plexus
7
Parts of the GIT without serosa
Esophagus; most of the rectum
8
3 Components of GI regulatory system
CNS, Enteric Nervous System; Enteroendocrine cells
9
Differentiate short reflex and long reflex in the GIT
Short reflex: signals from chemoreceptors, osmoreceptors, mechanoreceptors reach nerve plexus and smooth muscle/glands producing a response; Long: signaling involves spinal cord and brain
10
T/F smooth muscle lack cross- striations and thick an thin filaments
F
11
Cellular components that helps in efficiency of contractions
dense bodies
12
T/F GI smooth muscle act as one, are fast acting, hence more efficient
F; act as one, SLOW acting; more efficient
13
what does contraction of the longitudinal muscle layer do? circular?
L: decrease length
C: decrease diameter
14
Functions of UES
voluntary control of swallowing (e.g. option not to swallow spoiled food)
prevents:
entry of air into trachea; gas into esophagus
15
T/F the LES is anatomically distinct
F; physiological only
16
Which anal sphincter contributes the most to maintaining fecal continence?
Internal Anal Sphincter (70-80%)
17
pacemaker of the GI
Interstitial Cells of Cajal
18
The vagus nerve provides parasympathetic (stimulatory) innervation for the GIT. After Vagotomy, will GI motility cease?
No. as long as Interstitial cells of Cajal is intact, there will be GI Motility
19
T/F No ICC no GI motility
T
20
What cellular feature of the ICC make them act as one functional unit?
gap junctions
21
T/F much of the neural and hormonal regulation of GI functions are intrinsic to the GIT
T
22
Parasympathetic innervation of the GI from the esophagus to the ascending colon is via which nerves?
vagus nerves
23
Parasympathetic innervation of the GI from the transverse colon to rectum is via which nerves?
Pelvic nerves
24
Resting membrane potential of smooth muscle
-56mV
25
slow undulating changes in RMP
slow waves
26
True action potential that produces AP
<-40mV
27
T/F higher slow waves = less spike potential
F
28
T/F muscle contractions produced by spike potential is greater in force than contractions produced by slow waves
F; slow waves do not produce AP; therefore comparison can't be done
29
what stimulate spike potentials?
stretch, Ach
30
what does sympathetic innervation do to the membrane potential? what does this imply?
hyperpolarize from -56 to -70mV; inhibition - decrease muscle contraction
31
T/F contractile force increase with number of APs
T because of temporal summation
32
GIT segments in decreasing order of contraction rate
Stomach - 3/min
Sphincter of Oddi - 4/min
Colon - 6/min
Ileum -9/min
Jejunum -11/min
Duodenum - 12/min
33
contraction is facilitates by _______ and _______; relaxation is facilitated by ___ and ___
Ach, tachykinins; VIP, NO
34
[analogy] Peristalsis:transit::Segmentation:______
mixing
35
Long sustained contraction that serve to limit flow
Tonic Contraction
36
what kind of movement are peristalsis ans segmentation?
phasic
37
which is more important? segmentation or peristalsis?
segmentation
38
causes of tonic contraction
repititive spike potentials, continuous depolarization of smooth muscle by hormones, continuous entry of Ca2+
39
The pylorus can only empty particles that <1mm in diameter. how are these removed?
MMC; specifically phase III
40
which MMC phase is absent in Diabetics?
Phase III; thus bezoar forms
41
what stimulates MMC?
motilin; erythromycin
42
Fed pattern vs MMC
fed pattern: contractions are longer but weaker
MMC: stronger contractions; shorter duration
43
T/F fed pattern lasts longer with fatty food
T; harder to digest
44
areas of the GIT without MMC
esophagus and colon
45
Segment with longest transit time; shortest? what are the implications of transit time?
longest: colon; more susceptible to CA
shortest: esophagus; less susceptible to CA
46
What is the implication of a lower thoracic pressure compared to abdominal pressure?
chyme would tend to go up the esophagus from abdominal to thoracic part;
47
which has a greater resting pressure, UES or LES? what does the difference imply?
UES(50-150)>LES(15-50); UES can prevent reflux into respiratory tree
48
What controls UES tonic contraction?LES?
neural via vagus; hormonal(VIP, NO) and neural (Vagus)
49
after how many days of fasting will GI motility decrease to conserve energy?
4
50
3 phases of swallowing
oral
pharyngeal
esophageal
51
which esophageal peristalsis has no relation to food intake?
tertiary
52
condition characterized by not having enough nerves in distal esophagus
achalasia
53
parasympathetic and sympathetic innervation of stomach
vagus; celiac nerves
54
empty stomach fasting vol and resting pressure
>=50mL; 7-50mmHg
55
what is the trend of action potential as you go down the stomach
increase
56
what allows the stomach to accommodate large volumes with little increase in intragastric pressure
volume adaptation phenomenon
57
Which empties faster, liquid/solid?
liquid;
58
T/F if the first portion of the name of the reflex is anatomically more proximal than the second part, the reflex is inhibitory, otherwise excitatory
excitatory; inhibitory
59
where is the vomiting center located?
medulla; specifically obex
60
In retching, why is it that nothing comes out when one 'vomits'
because UES does not relax
61
what complication can result from severe retching?
tear of LES
62
Steps in vomiting
deep inspiration
closure of glottis
elevation of soft palate
diaphragm contraction
ab muscles contractiob
LES UES relaxation
Gastric contents into esophagus
63
describe the gastrocolic reflex
colon gets stimulated after eating due to distension of stomach(presence of food) and products of digestion in small intestine; mass movements are initiated reulting to urge to defecate
64
What is the only proximal-to-distally named reflex that is inhibitory?
Rectoanal reflex
65
What happens when there's a lot of accumulated feces in the rectum?
rectoanal reflex; inc pressure, dec in IAS pressure. feces can still be held due to EAS
66
Constipation vs. Obstipation
Constipation: defecation less than 3x a week
Obstipation: no passage of stool/ flatus secondary to obstruction
67
What causes relaxation of Sphincter of Oddi?
CCK
68
What are the causes of gall bladder contraction?
Secretin; bile acids, vagal stimulation
69
[analogy] Proximal obstruction: extreme vomiting:: Low/Colon obstruction: ________
extreme constipatiob
70
[symptoms] obstruction in the esophagus
vomiting (non acidic)
71
[symptoms] obstruction in the pylorus
acidic vomitus
72
[symptoms] obstruction in the proximal and 2nd part of duodenum
neutral-basic vomitus
73
[symptoms] obstruction in the below duodenum before right colon
neutral-basic vomitus with bile stain
74
[symptoms] obstruction in the R colon
diarrhea
75
[symptoms] obstruction in the L colob
constipation
76
difficulty in swallowing
dysphagia
77
