EXAM 3 - Respiratory System, Digestive System, and Metabolism Flashcards
1
Q
mucosal epithelium
A
most variable feature in GI
enterocytes, endocrine, exocrine
cell/cell junctions
GI stem cells
2
Q
lamina propria
A
connective tissue contains nerve fibers, vessels, and lymph nodes
wandering immune cells, Peyer’s patch
3
Q
muscularis mucosae
A
thin layer of smooth muscle
shape intestinal folds, move the villi
4
Q
mucosa
A
important in secretion, digestion, and absorption
5
Q
digestive enzymes
A
secreted by exocrine glands or epithelial cells
may remain bound to apical membranes of intestinal cells
6
Q
exocrine galnds
A
salivary glands, pancreas
7
Q
epithelial cell secretion
A
in stomach and small intestine
8
Q
brush border enzymes
A
digestive enzymes that remain bound to apical membranes of intestinal cells
9
Q
zymogens
A
need to be activated into enzyme
10
Q
mucus
A
secreted by exocrine cells
11
Q
exocrine cell
A
mucous cells, salivary glands, goblet cells
12
Q
function of mcuus
A
protect GI mucosa; lubrication
13
Q
mucus stimulation
A
parasympathetic
neuropeptides
cytokines
14
Q
submucosa
A
loose connective tissue containing larger blood and lymph vessels
transport absorbed nutrient
15
Q
submucosal plexus
A
meissner’s plexus
nerve supply to muscularis mucosae
16
Q
muscularis externa
A
two layers of smooth muscle
Inner: circular
outer: longitudinal
17
Q
myenteric plexus
A
auerbach’s plexus
in muscularis externa
between 2 muscle layers
18
Q
GI smooth muscle spontaneous contraction
A
peristalsis
segmentation
19
Q
peristalsis
A
move food along
20
Q
segmentation
A
mix food and break it down
21
Q
contraction frequency of GI smooth muscle is set by
A
Basic Electrical Rhythm (BER) and chemical input
22
Q
basic electrical rhythm
A
slow waves (3-20s) set by pacemaker cells (interstitial cells of Cajal)
23
Q
interstitial cells of cajal
A
modified smooth muscle cells between muscle and nerve plexus that set BER
24
Q
phasic contractions
A
posterior portion of the stomach; small intestine
25
tonic contractions
sphincters; anterior portion of the stomach
26
after a meal
peristalsis and segmentation
27
peristalsis after a meal
contraction AND distal relaxation
esophagus
stomach
intestinal
28
segmentation after a meal
contractile rings
| small and large intestine
29
between meals
migrating motor complex for housekeeping
30
enteric nervous system (ENS)
acts independently, shares many features of CNS
primarily on motility and secretion
31
features of ENS
intrinsic neurons
responds to many NTs and GI peptides
glial cells
diffusion barrier
integrating center
32
motility excitatory NTs and GI peptides
```
ach (gi)
substance P (gq)
```
33
motility inhibitory NTs and GI peptides
NO
| vasoactive intestinal polypeptide (VIP)
34
secretomotor ENS
Ach, VIP
35
GI peptides
secreted by isolated endocrine cells in mucosa
| not limited to GI functions
36
long reflex
can originate anywhere
integrated in the CNS
cephalic reflex
37
short reflex
originate in ENS, integrated in ENS
gastric emptying
38
the cephalic phase of digestion
long reflexes initiated in the brain
```
function and secretion of saliva
swallowing reflex
```
39
functions of saliva
softens and lubricates food
chemical digestion
taste
protection
40
saliva: chemical digestion
salivary amylase and some lipase
41
saliva: protection
lysozyme, immunoglobulins, fluoride, HCO3-
42
saliva: glands
parotid glands
sublingual glands
submandibular glands
43
parotid glands
watery solution
44
sublingual glands
mucus solution
45
submandibular glands
mixed secretion
46
salivary secretion
2 steps:
acinar cells
ductal cells
47
acinar cells
resembles extracellular fluid
48
ductal cells
absorb Na+ and Cl-
secrete K+ and HCO3-
net removal of solute
impermeable to water
49
stimulation of salivary secretion
ductal modification reduces
| HCO3- remains high by action of secretagogues
50
swallowing reflex
primary peristalsis and secondary repetitive peristalsis
51
gastroesophageal junction
resting pressure: 30mmHg
52
substances that reduce pressure of gastroesophageal junction
alcohol
caffeine
cigarette smoke
chocolate
53
pathological conditions of gastroesophageal junction
Gastroesophageal reflux disease (GERD)
achalasia
54
achalasia
nerve cells (myenteric plexus) that innervate esophageal muscle degenerate
55
symptoms of achalasia
solid dysphagia
fullness in chest while eating
chest pain
weight loss
56
gastric phase
series of short reflexes initiated when food enters the stomach
57
topics in gastric phase
secretion of the stomach
| motility of the stomach
58
proximal anatomy of stomach
anterior
cardia
fundus
body
59
distal anatomy of stomach
posterior
antrum (pyloric region)
pyloric sphincter
60
functional regions of the stomach
proximal (reservoir)
| distal (pump, grinder)
61
structures to support stomach functions
rugae
| oblique layer overlying mucosa
62
LES (esophagus) and cardia secretion
mucus
| HCO3-
63
LES (esophagus) and cardia motility
prevention of reflux
entry of food
regulation of belching
64
fundus and body secretion
```
H+
intrinsic factor
mucus
HCO3-
pepsinogens
lipase
```
65
fundus and body motility
reservoir
| tonic force during emptying
66
antrum and pylorus secretion
mucus
| HCO3-
67
antrum and pylorus motility
mixing
grinding
sieving
regulation of emptying
68
gastric secretions
gastrin
acid
enzyme
paracrine
69
gastric secretion: gastrin secretion
G cells
70
gastric secretion: gastrin is triggered by
vagus nerve stimulation (Gastrin-Releasing Polypeptide, GRP)
amino acids
gastrin increases with food intake because acid denatures proteins
71
gastric secretion: gastrin is inhibited by
acid, somatostatin
72
gastric secretion: gastrin function
acts on parietal and ECL (arterial) cells (CCK-B receptor)
stimulates acid release
stimulates mucosa growth in stomach, small and large intestine
73
gastric secretion: acid is secreted by
parietal cells in gastric glands
74
gastric secretion: acid is stimulated by
gastrin, Ach, histamine
75
gastric secretion: acid is inhibited by
prostaglandin E2 and somatostatin
76
what inhibits the gastrin feedback loop?
acid and somatostatin
77
somatostatin
B cells secrete this; local (paracrine)
78
arterial cells
secrete histamine
79
histamine
stimulator for acid secretion
80
alkaline tide
after eating, HCO3- enters blood
81
parietal cell activation
tubulovesicular membrane and intravesicular caniculus fuse with cell membrane and eachother
H+/ATP pump is rate limiting factor
82
What mechanism will inhibit HCl secretion?
A. M3 receptor agonist
B. H2 receptor agonist
C. Activation of Gi-coupled receptor
D. Activation of Gq-coupled receptor
Activation of Gi-coupled receptor
83
gastric secretion: enzyme secretion
pepsin and gastric lipase
84
pepsin is effective on
collagen
85
gastric secretion: enzyme secretion process
chief cells secrete pepsinogen
HCl in stomach activates to pepsin
gastric lipase is co secreted with pepsin
in small intestine pepsinogen is neutralized with bicarbonate and inactivates pepsin
86
gastric secretion: paracrine secretion
histamine
intrinsic factor
somatostatin
87
paracrine secretion: histamine
secreted by ECL cells and stimulated by gastrin and Ach
88
paracrine secretion: intrinsic factor
secreted by parietal cells; critical for B12 absorption
89
paracrine secretion: somatostatin
secreted by D cells; primary feedback signal
90
Which of the following treatments will alleviate the symptoms of peptic ulcer disease?
A. H+/K+/ATPase activator
B. H2 receptor agonist
C. M3 receptor agonist
D. Somatostatin release
D. somatostatin release
All the rest would cause increase of acid
91
A drug that blocks the fusion of tubulovesicular membrane and intracellular canaliculus in parietal cells would result in...
A. an increased production of HCl
B. an increased production of pepsinogen by chief cells
C. an increased protein digestion in the stomach
D. a decreased somatostatin production
E. an increased catalytic activity of pepsin
D. a decreased somatostatin production
92
control of gastric secretion
vagal activation stimulates multiple cell responses via NT (Ach and GRP)
93
what stimulates the parietal cell?
Ach, gastrin, histamine
94
what inhibits gastrin?
acid in the antrum stimulates somatostatin release to inhibit meal-stimulated gastrin secretion
95
motor functions of the stomach: storage
proximal portion (fundus and body)
receptive relaxation
adaptive relaxation
96
receptive relaxation in the stomach
relaxation of stomach muscles as food moves through esophagus and enters stomach
97
adaptive relaxation of stomach
relaxation of stomach muscles when filled
98
motor functions of the stomach: mixing
```
distal portion (antrum)
peristalsis
```
99
control of gastric motility in the gastric phase
```
neural control (vagovagal reflexes)
mechanical stimulation
chemical stimulation
```
100
absorption by the stoamch
aspirin, other weak acids; EtOH
stomach wall is not specialized for absorption
101
protection of the stomach wall
thick, alkaline mucus
tight junctions between epithelial cells
rapid replacement by GI stem cells
102
gastric ulcers
destruction of the lining of gastric mucosa
103
results of Warren & Marshall's study
when treated with antibiotics, 80% of patients were permanently cured of their ulcers
104
primary causes of ulcers
infections (H. pylori)
| NSAID
105
NSAID
inhibits mucus production, causes ulcers
106
Zollinger-ellison syndrome
ulcers caused by over secretion of gastric acid
rare
107
intestinal phase
series of responses after chyme enters the small intestine
108
intestinal phase topics
gastric emptying
motility and secretion of small intestine
secretion of accessary organs
digestion and absorption of fat, carbohydrates, and proteins
109
gross anatomy of small intestine
duodenum (common bile duct + pancreatic duct) to jejunum to ileum
110
ileum
peyer's patches or lymph nodules
| ileocecal valve
111
structures to support small intestine functions
plicae (circular folds)
villi
microvilli
112
gastric emptying
strong peristaltic waves in gastric pump
increased tone in gastric reservoir
opening of pylorus
inhibition of duodenal segmental contractions
113
increase gastric emptying
hormonal: gastrin
gastric volume
neural
114
decrease gastric emptying
distension plus acid in duodenum (enterogastric reflex)
hormonal: GIP, CCK, secretin
115
The gastric emptying rate can be increased by
increased peristaltic wave in gastric pump
increased tonic contraction in gastric reservoir
increased action of VIP in the pyloric sphincter
116
dumping syndrome
gastrectomy may lead to loss of feedback control of emptying
partly digested food draws excess fluid into intestine
may have malabsorption
117
intestinal secretion
cholecystokinin (CCK)
| secretin
118
cholecystokinin is secreted by
I cells (mucosa of the upper small intestine)
119
cholecystokinin functions
stimulates pancreatic enzyme secretion (augment secretin functions)
contraction of gallbladder
relaxation of sphincter of Oddi
inhibit gastric emptying and gastric secretion
120
cholecystokinin is triggered by
amino acids, peptides, and fatty acids
121
cholecystokinin is inhibited when
products of digestion move on to the lower portion
122
secretion is secreted by
S cells (mucosa of the upper small intestine)
123
secretion functions
stimulate pancreatic bicarbonate secretion (augment CCK functions)
inhibit gastric emptying and gastric secretion
124
secretion is triggered by
acid, products of protein digestion
125
secretion is inhibited when
products of digestion move on to the lower portion
126
small intestine motility
segmentation
peristalsis
migrating motor complex (MMC)
127
segmentation in small intestine
mixing
| slow propulsion possible due to frequency gradient
128
peristalsis in small intestine
weak
129
migrating motor complex (MMC) and MOTILIN
stimulating
130
migrating motor complex (MMC) and FEEDING
inhibits MMCs
131
digestion of carbohydrates
can only be absorbed as monosaccharides
amylase for smaller glucose chains and disaccharides
brush border enzymes
132
brush border enzymes
disaccharidases
133
absorption of carbohydrates: apical side
SGLT1
| GLUT5
134
SGLT1
secondary active; glucose and galactose
high affinity for glucose; regulated by glucose in intestine
135
GLUT5
facilitated diffusion
| fructose
136
absorption of carbohydrates: basolateral side
GLUT2 for all monosaccharides
137
digestion of protein
endopeptidases
| exopeptidases
138
endopeptidases
proteases; attack peptide bonds
139
endopeptidase secretion
by stomach, intestine, and pancreas as inactive proenzymes
140
exopeptidases
release single amino acids
secreted by the pancreas
141
endopeptidase examples
pepsin, trypsin
142
exopeptidase examples
carboxypeptidase
143
absorption of a protein
absorbed as amino acids, dipeptides and tripeptides, and rarely larger peptides
144
absorption of a protein as amino acids
Na+ dependent active transport
145
absorption of a protein as dipeptides and tripeptides
H+ dependent; PepT1
146
absorption of a protein as larger peptides
transcytosis
may elicit allergic response
more in infant
147
digestion of fat
emulsification
enzymatic fat digestion
formation of bile micelles
148
digestion of fat: emulsification
bile salts
breaks down large lipid droplets to smaller ones
increase surface available for lipase action
149
digestion of fat: enzymatic fat digestion
lipase and colipase digest triglycerides into monoglycerides and fatty acids
phospholipase digests phospholipids
150
digestion of fat: formation of bile micelles
break down and reform constantly
| break down to be absorbed
151
absorption of fat
enter apical membrane
inside the cells
leave basolateral membrane
152
absorption of fat: monoglycerides and fatty acids in apical membrane
diffusion
153
absorption of fat: cholesterol in apical membrane
transporter
154
absorption of fat: inside the cells
monoglycerides and fatty acids recombine
chylomicrons formation
155
absorption of fat: leave basolateral membrane
via exocytosis
156
transport of absorbed nutrients
products of carbohydrates and proteins are absorbed into the hepatic portal system
products of fat digestion (chylomicrons) enter lacteal
157
product of fat digestion
chylomicrons
158
hepatic portal system
blood leaving gut enters hepatic portal vein
brought directly to liver
second exchange site at liver sinusoids
most absorbed nutrients go to liver first (except products of fat digestion)
159
functions of liver
metabolic regulation
synthesis
storage
detoxification
160
functions of liver: metabolic regulation
maintain normal blood glucose levels
carbohydrate, lipid, amino acid metabolism
161
functions of liver: synthesis
plasma protein; clotting factors; bile; cholesterol
162
functions of liver: storage
iron, glycogen, blood, fat-soluble vitamins
163
functions of liver: detoxification
alcohol and other drugs
164
peritoneum
serous membranes within abdominal cavity
| supports blood vessels, nerves, and lymphatic vessels
165
parietal peritoneum
inside surface of body wall
166
visceral peritoneum
surface of internal organs
167
peritoneal fluid
produced by serous membrane lining
provides lubrication
intraperitoneal organs
retroperitoneal organs
168
duodenum
common bile duct and pancreatic duct
169
ileum
peyer's pathches or lymph nodules
| ileocecal valve
170
structures in small intestine
plicae (circular folds)
villi
microvilli
171
mesentery
continuous, formed by peritoneum
172
mucus secretion is stimulated by
parasympathetic NS
neuropeptides
cytokines
173
digestive enzymes
secreted by exocrine glands and epithelial cells
remain bound to apical membranes or secreted as zymogens
174
exocrine glands
salivary and pancreas
175
epithelial cell secretions
stomach and pancreas
176
mucus
protects, lubricates
177
motilin
released during fasting, targets GI and stomach, MMC effector
