Gastrointestinal Physiology- 1 Flashcards
GI Overview Motility, Secretion- Mouth and Esophagus Gastric Phases
1
Q
vascular bed and adrenergic sympathetic cells
A
vascular bed constriction
2
Q
The stomach paracrine signal of ECL
A
histamine
3
Q
local circuit coordination of peristalsis
A
sensory –> enteric interneurons (myenteric plexus) –> excit/inhib motor neurtons
4
Q
During the inhibition of gastric acid secretion, D cells are stimulated by this to produce a compund that functions both as a hormone and a paracrine signal.
A
D cell stimulation by: luminal acid and gastrin
D cell secretion- somatostatin
D cell inhibition by: ACh
5
Q
cephalic phase- results and consequences
A
inc. excit parasympathetic outflow to the GI from brain stem. leads to salivation, gastric secretion, pancreatic secretion, galbladder secretion, relaxation of the sphincter of the oddi
6
Q
Name a hormone that a- increases motility b- decrease motility
A
a- motilin- M cells b- somatostatin and GIP- ( From D cells and K cells)
7
Q
distention of the duodenum relaxes the orad portion of stomach via local enteric circuit. And nutrients in duodenum incudes the release of this hormone
A
cholecystokinin (CCK)
8
Q
The duration of Ca++ based- muscle action potential - Basics of muscle oscillation
A
long
9
Q
emptying rate of isotonic fluid (osmolality of the content)
A
rapid
10
Q
The action potential that occurs on top of slow waves
A
induce contraction with a frequency dependent upon the frequency of the underlying waves
11
Q
salivary acinar cells
A
secrete protein and mucus in an isotonic solution
12
Q
Cephalic Phase
In response to these compounds parietal cells release acid during the cephalic phase
A
Ach, Histamin and Gastrin
13
Q
accessory organs of GI
A
pancreas, liver, gall bladder, parotid glands, salivary glands
14
Q
location of M cells, and function
A
Duodenum and jejunum- secrete motilin increase motility
15
Q
This sub-layer of the gut wall contains the following: capillaries, central lymph vessel, lymphoid tissue and glands with ducts that allow the mucus and serous secretions into the mucosal surface.
A
lamina propria
16
Q
CN V
A
trigeminal
17
Q
GI location dependent frequency stomach duodenum colon
A
the freq of slow waves varies with location along the GI tract. Ranges from 1-3 cyc/min in the caudad region of the somach to 12 cyc/min in duodenum. Then progressively lower to 2-4 in the colon.
18
Q
Stimulation of Gastric Acid Secretion During the Intestinal Phase
A
During the intestinal phase the products of protein digestions stimulate intestinal G cells to secrete Gastrin
19
Q
digested last in the stomach
A
little mixing occurs in orad section fat forms a layer on top of the other stomach content and is digested last.
20
Q
digestion stops along this GI portion
A
large intestine
21
Q
Pernicious anemia
cause and treatment
A
anemia caused by B-12 deficiency due to absence of IF
Gastric bypass surgery- prescribed for morbid obesity- eliminates the IF production.
Treatment- B12 injection ( oral administeration not as effective)
22
Q
Which part of the stomach contracts during the emptying phase
A
orad
23
Q
Name a cell type that is both oxynic and pyloric
A
D cells- secrete somatostatin
24
Q
function of submucosal plexus
A
stimulates secretion and promotes digestion
25
the phase in which the secretion of salivary glands is stimulated
cephalic phase
26
distention of the duodenum relaxes the orad portion of stomach via this circuit.
local enteric circuit- during the feedback relaxation
27
detect content of the chime and control the pylorus
chemoreceptors of duodenum and illium
28
A thin sheet of CT outside of mucosa
lamina propria (mucosa layer composed of: mucosal epithelium, lamina propria and muscularis mucosae)
29
relaxation of the sphincter of the oddi is the result of this phase
cephalic phase
30
What follows after the entery of acid into duodenum
entery of acid into duodenum --\> S cell stimulation --\> secretin (hormone) release --\> cheif cell stimulation --\> pepsinogen secretion
31
uvula moves up
nasopharynx blocked passage to pharynx opens
32
site of submucosal plexus
submucosa
33
the pathway of gastric reflex that is called gastro-gastric reflex
adaptive relaxation reduction of muscle tone via local enteric circuits
34
Regulation of pepsinogen
1- secretion in response to ACh
2- entery of acid into duodenum
35
emptying of low PH chime
low PH slow emptying
36
The sub layer next to the serosa
longitudinal outer layer (thick smooth muscle layer- externa)
37
Gastric anatomy divisions of the stomach
fundus, body, antrum
38
metaplasia Example- gastroesophageal reflux disease (GERD)
transformation of one adult cell type into another. In GERD--\> esophageal epithelium differentiate from a stratified squamous form into columnar.
39
primary goal of submucosal plexus and its fiber type
to stimulate secretions required for digestion afferent fibers
40
Duodenum chemoreceptors detect acid, fat, tonicity and products of protein degradation. In response, the followings are released:
CCK GIP Gastrin All induce contraction of the pylorus
41
CN X
vagus
42
Contraction of pyloric S. induced by ------ and relaxation induced by ------.
contraction-excitation relaxation- inhibition
43
Contraction begins in middle of body and gets progressively stronger toward ----------- sphincter. gastric patterns of motility
pyloric sphincter
44
site of myenteric plexus
muscularis propria, between the inner circular and outer longitudinal muscle layers
45
hepatic portal vein empties into
the liver
46
regulators of motility within GI
intrinsic and extrinsic factors
47
Hormonal regulation of pylurus The hormone(s) that induce contraction of the pylorus
CCK, GIP and Gastrin
48
layers of the gut wall ( from innermost)
mucosa submucosa muscularis propria serosa
49
areas covered by submucosal plexus and myenteric plexus
submucosal- limited to SI and LI myenteric extends through the entire GI
50
Sympathetic projection of enteric NS
via PREvertebral ganglia
51
blood glucose and regulation of food intake
direct and indirect (via insulin) inhibits feeding
52
regulation of deglutition
swallowing is regulated by CNS's brainstem swallowing center. info travels in trigeminal, vagus, and glossopharyngeal nerves.
53
protects B12 from bacterial degradation in the gut
IF
54
CN IX
glossopharyngeal
55
activation of mechano and chemo receptors that and consequent reduction of muscle tone via local enteric circuits is a response to
gastrin release by gastric cells
56
the basis of slow waves
ICC
57
gherlin
GI hunger hormone
58
serosa is absent in this portion of the intestinal tract. This portion instead is bounded by a fibrous covering termed adventitia.
esophagous
59
vascular bed and parasympathetic release of VIP and ACh
vascular bed dialation- ACh via NO. (see autonomic lecture)
60
The absence of this layer contribute to the tendency of esophageal cancers to spread locally before detection, and the subsequent poor prognosis of this type of cancer.
serosa is absent- instead fibrous covering-adventitia
61
breathing resumes at the end of this phase
oropharyngeal- when the Upper. E. S relaxes and bolus enters the esophagus
62
the largest endocrine organ
GI- known as enteric endocrine system
63
Name several oxynic glands and their secretions
mucous neck cells- mucus and bicarbonate
parietal cell- HCL and Intrinsic factor
enterochromaffin-like cell (ECL)- histamine, an HCL regulator
Chief cell- pepsinogen and gastric lipase
64
myoepithelial cells of salivary gland
eject saliva into mouth when stimulated by ANS
65
Stimulation of Gastric Acid Release During the Gastric phase
1- distention of the stamach --\>
a- reflexive ACh from ENS
b- activation of preganglionic parasympathetic cells
2- similar consequences as the cephalic phgase: histamine release from ECL and Gastrin release from G cell. Gastrin functioning as a hormone
3- Gastrin stimulates acid secretion by parietal cells
4- G cells are stimulated by the products of protein digestion
66
two methods by which myenteric plexus increases intestinal motility
1- stimulating peristalsis 2- inhibiting sphincter contraction
67
The inner and outer muscular layers of externa (muscularis propria)
inner circular outer longitudinal
68
esophageal phase
when food is transferred to the esophagus transport of the food from mouth to stomach and protection of airways from food
69
parasympathetic innervation of enteric NS
PREGANGLIONIC PARASYMPATHETIC cells innervate the enteric NS
70
slow waves are initiated at this boundry
orad and caudad
71
salivary ductal cells
alter acinar secretion by differential absorption and secretion of ions resulting in hypotonic saliva
72
PP (pancreatic poly peptide)
PP is an inhibitory hormone from the pancreases- inhibits search for food and feeding behavior.
73
serous
watery secretion
74
Inhibition of Gastric Acid Secretion
The cells involved
a- stimulation of D cells
b- inhibition of parietal cells
c- furthur inhibition of other cells
d- D cell inhibition
75
inhibitory motor neurons that are activated by excitatory neurons secret (during gastric relaxation)
VIP and NO
76
The most important component in regulation of saliva secretion and blood flow
regulated by ANS with the PARASYMPATHETIC being the most important.
77
Major triggers for mucus exocytosis
ACh secreted by:
parasympathetic postganglionic cells
and
prostaglandins
78
Through receiving the input from enteric neurons, these cells can influence amplitude of slow waves but not frequency.
Amp and not freq. is impacted once the ICC cells receive input from enteric neurons.
79
vascular supply of the intestinal tract
celiac a. Superior Mesenteric Artery- SMA IMA
80
Name an endoprotease, produced in an inactive form
Pepsinogen --\> acidic condition --\> pepsin
PH\< 3.5
81
the phase before food is ingested
cephalic phase
82
stimulation of secretion
1- cholinergic parasympathetic via CN VII and CNIX --\> muscarinic receptor --\> PKA activation --\> inc. [Ca2+] --\> secretion 2- adrenergic sympathetic --\> secretion \_DIRECT and adrenergic symp --\> [Ca2+] inc. --\> secretion
83
smooth muscle of LES
high tension due to cholinergic input from parasympathetic tonic tension due to myogenic (latch state). less negative resting membrane potential spontaneous AP firing
84
symptoms of gastroparesis
delayed stomach emptying and severe vomitting
85
medication with Xerostomia side effect
medications with anticholinergic properties such as antipsychotics have dry mouth side effects
86
Components of lamina propria
connective fiber matrix with cells of immune system, lymph and blood vv.
87
this phase activates GI for ingestion
cephalic phase
88
hepatic portal vein and hepatic arteries empty into
live (2nd capillary)
89
a-amylase is secreted by and functions in
acinar cells and begins starch digestion- also travels with the food
90
the two arteries that empty into the 1st capillary beds
splenic artery and mesenteric artery
91
emptying rate depends on
content of the chime particle size strength of gastric contraction and the pressure gradient between the antrum and duodenum
92
secretory cells of SI
goblet enteroendocrine tuft paneth
93
emptying rate and the following contents: amino acids and fats
both slow emptying rate
94
the morphology of epithelial cells of the esophagus (mucosa layer)
stratified squamus
95
Two ways to activate pepsinogen
a- acidic condition and an spontaneous breakdown of pepsinogen to pepsin
b- active pepsin can also digest pepsinogen
96
Stimulates D cells to secrete somatostatin
Hint: Putting on the breaks
Gastrin stimulates D cells to secrete somatostatin
97
Intrinsic factor (IF)
reguired for vitamin B12 (cobalamin) absorption
protects B12 from gut bacterial degradation
critical for DNA synthesis, amino acid metabolism and gatty acid metabolism.
Its defeciency profoundly effects blood and CNS.
98
Its distention relaxes the orad portion of stomach
duodenum- during feedback relaxation
99
pacemaker activity due to opening of Ca dependent Cl channel results in
repolarization
100
produced by K cells in the duodenum and jejunum
Gastric Inhibitory Polypeptide- inhibits gastric motility
101
net H+ movement in the duct of salivary gland
absorption
102
Total number of neurons in enteric nervous system
equals the total number of neurons in spinal chord
103
Source of ACh during cephalic phase
Parasympathetic
104
water movement and acinar secretion
water movement largely paracellularly driven by ion export
105
A water- solubale vitamin that is critical for DNA synthesis, amino acid and fatty acid metabolism. It requires intrinsic factor for absorption.
Cobalamin- Vit. B12
106
compare the glia of enteric cells to that of CNS and periphery
the glia of enteric cell types are RELATED to glia of CNS rather than periphery.
107
Trigger for the release of secretin, a hormone, during the intestinal phase.
Entery of acid into duodenum triggers relerase of secretin from the S cells.
108
Stimulation of gastric acid secretion during:
a- cephalic phase
b- gastric phase
c- intestinal phase
a- ACh from parasympathetic, histamine, gastrin and gastrin as a hormone
b- Stomach distention, and ACh from reflexive ENS, gastrin as a hormone and digested protein particles
c- products of protein digestion
109
Na+ and Cl - concentration of saliva after modification compared to plasma
lower than plasma
110
\*\*\* The Frequency of the movement of content during mixing Orad--\> Caudad --\> Orad --\> Caudad
f= 15-20 secs
111
\* two phases that induce saliva secretion
cephalic and oral
112
Somatostain functions as a **hormone, not a paracrine signal,** to ihibit the following cells
Hint: inhibitiob of gastric acid secretion
parietal cell and ECL
113
weaker gastric contraction rate means
slower rate of emptying
114
high fat storage inhibits feeding via
leptin
115
NTS
hypothalamus, relay center, nucleus tractus solitarius
116
dephosphorylation of myosis during the latch state
dephosphorylation of myosin occurs before release of myosin from actin.
117
CCK release is triggered by this and causes muscle relaxation via this route- feedback relaxation.
nutrients in duodenum CCK --\> muscle relaxation via vagal route
118
electrical coupling of ICC
interstitial cells of cajal ICC are electrically coupled to each other and to UNITARY muscles
119
name 3 duct modification of secretion
modification of acinar secretion with respect to osmolarity, ion content and PH which occurs in the duct
120
muscularis mucosa is innervated by
submucosal plexus
121
covers glottis
epiglottis
122
GLP-1
Glucangon-Like -1 GI inhibitory hormone
123
the part of the brain which mediates the effect of GI, pancreas and adipocyte hormones participating in regulation of food iantake
hypothalamus mediates the affects of regulatory hormones
124
sepsis and GI microbiome
penetration of bacteria through GI is pathological and can result in sepsis
125
salivary gland cells
myoepithelial acinar ductal
126
vago-vegal reflex coordination of peristalsis
sensory --\> dorsal vegal complex --\> preganglionic parasympathetic neurons --\> excit/inhib motor neurons
127
LES- bolus entry is assisted by
orad peristaltic contraction and negative pressure in gastric cavity
128
part of hypothalamus that serves as a relay for some of the regulatory signals
NTS Nucleus tractus solitarius
129
NT of excitatory enteric neuron synapsing on ICC
ACh- muscarinic
130
swallowing
part of oral phase involuntary behavior, initiated by somatosensory neurons - somatic control and skeletal muscles
131
the three salivary glands
sublingual parotid submandibular
132
thiocyanite ion of saliva
a bactericide along with proteolytic enzymes that allows the bactericide to enter the bacteria
133
causes of hirschprung's disease
obstruction of the regions affected due to congenital absence of ENS in part of colon
134
ATP supply during latch state
NO CONTINUOUS ATP Supply
135
xerophthalmia
dry eyes
136
parasympathetic profection of enteric NS
via the vagus ( CNX) and Sacral spinal chord (lower 1/3 of colon)
137
mesenteric artery empties into
the 1st capillary bed of the intestine
138
plexus organization
organized into ganglia- 5 to a few hundred. Plexus are interconnected by nerve bundles to the ganglia
139
The base of muscle action potential - Basics of muscle oscillation
Ca2+
140
\*\* Regulation of all motility in pharynx and UES
reflexes between sensory and motor somatic division of NS.
141
axons of enteric neuronal cells
fine axons and unmyelinated
142
two phases of swallowing
oropharyngeal and esophageal
143
the differentiates cell types of SI
absorptive and secretory
144
EEC and ECL
enteroendocine cell and enterochromaffin-like cells are cells of enteric endocrine system that don't form glands but rather are scattered among the epithelial cells lining of the GI tract.
145
these cells of salivary gland (multilobulated) secret protein and mucus into an isotonic solution
acinar cells
146
the two blood supplies for the liver (2nd capillary bed)
hepatic portal vein and hepatic arteries
147
The cells of endocrine system that DO NOT form glands but rather are scattered among the epithelial lining of the GI tract
EEC and ECL
148
the site of a plexus which innervates the muscularis mucosae
submucosal plexus
149
PYY
peptide YY- GI inhibitory hormone
150
Sympathetic innervation of the enteric NS
POSTganglionic sympathetic cells innervate the enteric NS
151
xerostomia
dry mouth
152
outermost cellular membrane present in most of the intestinal tract that is continuous with peritoneal lining
serosa
153
pyloric stenosis
more freq in males- pylorus fails to relax after the meal symp: vomiting, malnutrition and dehydration
154
ovula contraction results in
blocking the nasal passage
155
BER
Basic Electrical Rhythm (slow wave)
156
Stimulate cheif cells to secrete pepsinogen
Secretin stimulates chief cells to secrete pepsinogen.
entery of acid into duodenum --\> S cell stimulation --\> secretin (hormone) release --\> cheif cell stimulation --\> pepsinogen secretion
157
this reflex causes brief relaxation of the fundus (gastric relaxation) when the food is detected in the mouth and pharynx
vago-vegal reflex during receptive relaxation
158
Major paracrine signals of the GI
5-HT from ECC histamine from ECL NO and Adenosine
159
serous fluid of saliva
dilutes the food
160
the sites of absorptions
small and large intestine
161
the side effects of anticholinergic medications
dry mouth and constipation
162
activation of pharyngeal pressure receptor sends messages to this center and leads to
activation of pharyngeal P. Receptor initiate reflexes from medulla ( swallowing centers)
163
\*\*\* slow wave
spontaneous oscillation of smooth muscle membrane potential. In the stomach and the rest of GI smooth muscles.
164
parasympathetic contact ------ neurons, which are
enteric neurons. enteric are the parasympathetic postganglionic cells
165
regulation of vascular dilation on salivary gland
vascular dilation is regulated by ANS and bradykinin- The latter paracrine is released by salivary gland in response to ANS stimulation
166
Elicits the reflexive release of ACh from enteric NS
Distention of the stomach
167
level of saliva secretion between meals except during sleep and during feeding
low level maintained High during feeding 1ml/min
168
fold of the epithelial cells in the large intestine (colon)
crypts
169
tonicity and PH of saliva
hypotonic with PH ~8
170
adaptive relaxation
induction of the activity inm mechano- and chemo- receptors that reduces muscle tone via local enteric circuits in response to gastrin release by gastric cells
171
HCO3- of saliva
buffering and reduction in bacterial growth
172
hypothesis for contracted muscles of the sphincter during closed state
muscles are in latch state
173
contraction of caudad section and its freq.
regular contraction. f= 3-4 cycles min
174
enteric nervous system
submucosal and myenteric plexuses
175
the salivary gland with mucus secretion
sublingual
176
Motilin
a hormone produced by M cells in duodenum and jejunum which increases motility
177
the term reserved for the endocrine cells that are not directly in contact with the blood
enterochromaffin-like cells (ECL)
178
distribution and location of GI microbiome
density varies with location some on epithelial surface and some in lumen
179
synchronizes the electrical activity of the smooth muscles of the GI
GAP junctions
180
composition of GI tracts from lower part of esophagus to anal external sphincter:
beyond the region of striated muscle, esophagus and rest of GI tract to anal external sphincter is composed of smooth muscle
181
--------- cells of this oxynic gland secrete pepsinogen.
Chiefcells
182
this layer is responsible for gross folds of the GI wall
muscularis mucosae (thin smooth muscle)
183
lingual lipase secreted by
ductal cells and begins lipid digestion
184
Name two cell types that are pyloric glands and their secretion
mucous cells- protective coaring, bicarbonate and mucus
G cells- gastin , an HCL regulator
185
GI inhibitory hormones
GLP-1, OXM and PYY
186
stimulation of taste and somatosensory afferents leads to this
initiation of production and secretion of secretory products in anticipation of ingestion. the stimulation of taste and somatosensory afferent ramps up the production as food enters the mouth,.
187
\*\*\*Freq and Amplitude regulation of contraction
Freq is intrinsic to stomach. ANS modifies amplitude: PNS- ACh- Increase Contraction SNS- decreases contraction
188
muscular composition of the pharynx and upper part of the esophagus
striated muscles controlled by somatic CNS
189
Acinar secretion
a- amylase acinar portion secrete enzymes, electrolytes in plasma like concentration (isotonic). besides Na+, CL-, K+ other ions exist in saliva: Ca2+, Mg2+ and F-
190
Two sources of ACh for regulation of pepsinogen
Secretion in response to ACh regulates pepsinogen
a- ACh (via PLC 2nd cascade) from enteric
b- ACh from parasympathetic (cephalic and gastric phases)
191
sustained tension during latch state
no additional ATP is required to sustain the tension --\> less o2 and ATP required by smooth muscles in this state
192
entrocytes
epithelial cells which absorb lumen content
193
pacemaker activity due to opening of Ca vot-gated channels at resting potential
depolarization
194
ICC and action potential
ICC don't fire action potential
195
control of pylorus to regulate the rate of emptying
hormones intrinsic reflexes via enteric symp. and parasym. input
196
UES is always closed except
deglutition UES relaxes during pharyngeal phase allow opening access to esophagus
197
Name 3 cells that produce a protective coating consisting of mucus and bicarbonate
mucous neck cells (oxynic gland)
mucous cells (pyloric gland)
surface epithelial cells
198
importance of electrolyte secretion within the GI
provides osmotic gradient
199
The role of GI STRETCH in regulation of food intake
stretch inhibits
200
cell types of epithelium
enterocytes, endocrine and secretory cells
201
an exception to the fact that adrenergic sympathetics do not operate directly on glands
stimulation of saliva secretion and inc. [Ca2+]
202
In the small intestine, the fold of the cells in mucosa are called ----- and each projection of each individual cell is called.
villi, microvilli
203
The stimuli and source of ACh during the gastric phase
Distention of the stomach during the gastric phase elicit reflecive release of ACH from the enteric NS.
204
relaxation of circular muscles orad --\> bolus is induced by
inhibitory enteric motor neurons
205
compare and contrast the submucosa layer with lamina propria
both are similar BUT submucosa layer contains secretory glands that extend up to epithelium and a neuronal network.
206
fold of epithelial cells in the intestine
villi
207
the shape of the epithelial cells of the GI tract
columnar
208
Cause of non-drug induced gastric ulcer
*Helicobacter pylori*
209
T/F Only parasympathetic visceral afferent is present in GI.
False Both parasympathetic and sympathetic visceral afferents are present.
210
5-HT
seretonin- a paracrine signal secreted from ECL
211
its stimulation increases intestinal motility by stimulating peristalsis and also by inhibiting contractions of sphincter muscles
myenteric plexus (located between inner circular and outer longitudinal muscle layers of muscularis propria
212
status of smooth muscles when sphincters are closed
contracted
213
three pathways of gastric relaxation
receptive, adaptive and feedback
214
peristalsis regulation
local circuit and vago-vagal reflex
215
------ is interposed between enteric motor neurons and smooth muscle
ICC- a specialized smooth muscle which is important element in regulating muscle contraction.
216
mucus component of saliva
glycoproteins and mucin
217
epithelial cells of the gut wall
stratified squamous in esophagus Columnar in GI until dentate line squamous in rectum
218
the phase corresponding to the food in the mouth
oral phase
219
components of the oral phase
taste sensation mechanical sensation mastication swallowing
220
Inhibition of Gastric Acid Secretion
Name the compounds involved for each section:
a- stimulation of D cells- somatostatin secretion
b- inhibition of parietal cells
c- furthur inhibition of other cells **(cells that stimulate pariatal cells)**
d- D cell inhibition
a- stimulation of D cells- by luminal acid and gastrin
b- inhibition of parietal cells- by somatostatin **_(Acting as a Hormone)_**
c- furthur inhibition of other cells.
G cell- somatostatin **_(as paracrine signal)_**
ECL cells- somatostatin **_(Hormone)_**
d- D cell inhibition- by ACh
221
the components of saliva
mucus, serous, a-amylase, lingual lipase, antibodies thiocyanate ion
222
OXM
Oxytomodulin GI- inhibitory hormone ( other GI inhibitory hormones are PYY, CCK and GLP-1)
223
closing of glottis is the result of this muscle contracting
laryngeal muscle contraction
224
PH range for pepsin activity
Pepsin only active when PH\< 3.5
acidic condition- pepsinogen --\> pepsin
as a result of spontaneous breakdown
Pepsin inactivated by PH\> 3.5
225
saliva
composed of numerous compounds such as mucin and enzymes
226
The sphincter between the small and large intestines
iliocecal
227
feeding inhibitory hormones secreted from the pancreas
insulin and PP
228
Orad section is ensheathed by --------- & --------- muscles.
thin and weak. Thus little mixing with fat oily layer on top.
229
the deglutition info start in brainstem swallowing center and travels down the following nerves:
trigeminal- CN V. vagus- CN X. glossopharyngeal- CN IX.
230
Regulation of Acid Secretion by Pepsinogen
polypeptides and amino acids products of pepsinogein digestion stimulate G cells
231
Chyme
once the content passes through the pylorus
232
HCO3- and K+ concentration of saliva after modification compared to plasma
higher concentration for K+ and HCO3-
233
targets of sympathetic projections
1- enteric neurons 2- smooth muscle 3- secretory cells 4- endocrine cells 5- ICC
234
muscles that contract during oropharyngeal stage
laryngeal muscle contraction and ovula contraction
235
pharyngeal phase
transport bolus to stomach
236
the two layers connected by submucosa
mucosa and muscularis propria
237
primary goal of myenteric plexus
coordination of intestinal motility
238
the salivary gland with serous secretion
parotid
239
two types of motor efferent
excitatory or inhibitory
240
ACh Action During Cephalic Phase
ACh drives histamine release from ECL and gastrin from G cells.
Gastrin, acts as hormone to furthur excite ECL and parietal cells.
241
contraction of circular muscles- orad --\> bolus- is induced by
excitatory enteric motor neurons via ICC. Transmitter of synapse on ICC is ACh- muscarinic.
242
effector substances that stimulate secretion
secretagogues
243
a layer of loose CT that connects the mucosa to the the layer containing thick smooth muscles (muscularis propria)
submucosa
244
efferent (neuronal) cell types
project to: 1- ICC- special smooth muscle 2- smooth muscle (all 3 layers and vasculature) 3- endocrine cells 4- secretory cells 5- endothelial smooth muscles
245
the enteric nervous system that extends through the entire GI tract
myenteric
246
enumerate the divisions of GI tract
mouth- pharynx (UES), esophagus (LES), stomach (Pyloric S), SI: duodenum. jejunum. ilium (iliocecal S), LI/colon: ascending. transverse. descending. sigmoid. rectum (internal anal and external anal Sphincters), anus. accessory organs
247
important element in muscle contraction
ICC- by forming a sheet of electrically coupled cells
248
motor unit of smooth muscles of GI
unitary motor unit
249
ICC
intestinal cells of cajal
250
afferent neuronal cells types
chemoreceptors and mechanoreceptors some send info to ANS ganglia
251
smooth muscle morphology
single nuc. spindle shaped when relaxed, globular when contracted NO myofibril NO sacromeres dense bodies similar to Z lines of muscle in protein constituents SR poorly developed and sparse NO T TUBULE
252
symptoms of Hirschprung's disease
no bowel movement w/in 48 hours of birth abdominal distention functional obstruction of the colon, typically sigmoid colon and vomitting
253
reflux through LES causes
GERD
254
\*Result of subthreshold depolarization
little or no contraction
255
Is required for cobalamin absorption
Vitamin B12
256
CCK
Cholecytokinin along with stretch inhibits feeding.
257
facilitate synchronized contraction of the GI unitary motor unit
GAP junctions between the cells to synchronize the electrical activity
258
blockage of food movement into larynx
epiglottis down larynx up
259
progenitor cells of SI and their location within SI
transit-amplifying (TA) along the walls of the crypt
260
ENS
third division of ANS same number of neurons as the spinal chord Autonomous to some extend without CNS input
261
retropulsion
As the food is pushed agst pyloric S. some may move into duodenum, while most is pushed back
262
mucus
viscous secretion
263
multiple thin layers of smooth muscle which, seperates the lamina propria from submucosa
muscularis mucosa
264
NT of inhibitory enteric motor neurons
VIP and NO
265
hypotonic saliva isdifferential absorption and secretion of the following ions by ductal cells
K+ and HCo3- added to saliva Na+ and Cl- taken away
266
The role of gastrin during cephalic phase
Gastrin (released from G cells in response to parasympathetic ACh), acts as a hormone to furthur excite ECL cells (secrete histamine) and Parietal cells.
267
Is secreted by parietal cells in response to the same stimuli that induce HCL secretion from thsoe cells
IF
268
emptying rate as the pressure gradient between the antrum and duodenum decreases
slower
269
Three distinct layers of mucosa ( the inner most layer of the gut wall)
mucosal epithelium lamina propria muscularis mucosa
270
Stem cells of the SI within the crypt
+4 stem cell QSC Crypt Base Columnar Cells CBCC/ASC
271
Release of ACh and the activation of preganglio nic parasympathetic cells are stimulated by ........ during gastric phase.
Waht is the consequences of such action
Distention of the stomach --\>
1- Reflexive ACh release from the ENS
2- Distention stimuli is relayed to the brainstem --\> activation of preganglionic parasympathatic cells.
Consequences are as in the cephalic phase
272
Somatostatin is also called
growth hormone-inhibiting hormone
273
the importance GI microbiome
important for nutrient absorption
274
Causes repolarization - basics of muscle oscillation
K+ efflux
275
receptive relaxation
vago-vagal reflex brief relaxation of the fundus when food is detected in the mouth and pharynx
276
degeneration of ICC in patient suffering from oxidative stress of diabetes lead to
diabetic gastroparesis
277
GIP
Gastric Inhibitory Polypepride
278
connection between the ganglia and plexus
nerve bundles
279
the most numerous cells of the epithelial layer of GI wall
enterocytes (absorption in lumen)
280
Drug induced gastric ulcer
aspirin damages the mucosa.
aspirin inhibits cyclooxygenase- COX- and enxyme in prostaglandin synthesis. In the stomach it modulates mucosal defense including eliciting mucus secretion.
281
intestinal cells of cajal
specialized smooth muscle form a sheet of electrically coupled cells
282
absorptive cells of the SI
entrocytes
283
Its receptors detect acids, fats, tonicity and products of protein degradation
chemoreceptors of duodenum
284
The main cause of xerostomia
due to: 1- increased viscosity of saliva because of vascular constriction and 2- inhibition of parasympathetic input
285
ICC network and oxidative stress
ICC volunarable to oxidative stress which occurs with diabetes
286
Name the layer of the gut wall that a- contains blood vessels b- contains a central lymph c- contains capillaries
a- submucosa b- lamina propria of mucosa c- lamina propria of mucosa
287
innervation of the lower 1/3 of colon
sacral spinal chord- a parasympathetic projection
288
triggers of cephalic phase
cognitive olfactory auditory stimuli
289
feeding inhibitory hormones secreted by adipocytes
leptin
290
sphincters surrounding the anal canal
internal and external sphincters
291
D cells location and function
Location: Stomach, duodenum and the pancreatic islets Secrete somatostatin which inhibits motility.
292
interneurons of enteric cells
both ascending and descending
293
ECL
enterochromaffin-like cells of enteric endocrine system.
294
GI hormone that promotes feeding
the hunger hormone- gherlin
295
paracrine signals of enteric endocrine system
seretonin (5-HT) secreted from ECC- enterochromaffin cells stomach- histamine from ECL others NO and adenosine
296
fold of epithelial cells in the stomach
rugae
297
mastication (part of oral phase)
teeth (incisors and molars) mastication is reflexive for the most part leads to bolus formation and facilitation of taste
298
the GI component with the highest density of bacterial population
colong
299
oral phase
prepares food for swallowing
300
the long-term regulator of energy balance that functions by inhibiting food intake
leptin from adipocytes
301
emptying rate and the particle size
slower as the size inc. only particles \<1mm pass through
302
The hormones secreted from the cells of duodenum and jejunum that either increase or decrease gastric motility
increase- motilin (M cells) decrease- GIP (K cells)
303
Somatostain functions as **a paracrine signal and not a hormone** to ihibit the following cell(s).
Hint- inhibition of gastric acid secretion
G cells- somatostatin as a paracrine
Parital and ECL cell- somatostatin as a hormone
304
gives rise to efferent fibers that synapse directly on mucosal epitheliam
submucosal plexus
305
Activation of inhibitory motor neurons which secrete VIP and NO is by the release of ----------- from ---------. Gastric relaxation
ACh and substance P from excitatory neurons.
306
functional division of gastric anatomy and the muscular structure of each one
Orad- towards the mouth- thin smooth muscle layer caudad- thick smooth muscle layer.
307
excitatory neurons activate inhibitory motor neurons by secreting (during gastric relaxation).
ACh and Substance P
308
the layer that plays an important role in intestinal motility
muscularis propria (inner/circular- outer/longitudinal)
309
the major contributor of the maintenance of hypotonicity of saliva
hypotonicity maintained due to water impermeability of cells _ ductal\_ and removal of Na and Cl.
310
By being placed between 3 different muscle fibers form a 3D network
ICC Non-neuronal modified smooth muscle serve as the basis for slow waves
311
the enteric nervous system limited to small and large intestine
submucosal
312
chronic inflammation of exocrine glands- Symp: xerostomia (dry mouth), xerophthalmia (dry eyes), parotid gland enlargement, difficulty swallowing and difficulty with speech
Sjogren syndrome
313
trigger of relaxation for both UES and LES
arrival of peristaltic wave
314
\*\*\*\* The initiation of the underlying slow wave causing a freq, of 15-20/secs during mixing and for the following pattern Orad--\> Caudad --\> Orad --\> Caudad
underlying slow wave initiated at boundary of orad and caudad compartments.
315
\*\*\*\*Basic Electrical Rhythm
The regular depolarization-hyperpolarization cycles
316
second capillary bed empties into
hepatic vein
317
the salivary gland with both mucus and serous
submandibular gland
318
Third division of ANS
Enteric nervous system
