GI Secretions - intestines & pancreas & biliary Flashcards
(155 cards)
1
Q
in small and large intestine what cells secrete mucous
A
goblet cells
2
Q
where is mucous the most thick and strong
A
stomach
3
Q
what secretes bicarb
A
stomach
duodenum
colon
4
Q
what is the gland in duodenum that secretes bicarb
A
Brunner’s glands
5
Q
what activates Brunner’s glands
A
pH
6
Q
duodenal bicarb secretion is stimulated by
A
prostaglandins
7
Q
where does chloride secretion occur in small and large intestine
A
crypt glands
8
Q
what does chloride secretion do
A
promotes water flux to gut
9
Q
CFTR is dysfunctional in what disorder
A
cystic fibrosis
10
Q
bacterial toxins can act on second messenger systems and what will that do
A
chloride channel will not work properly, solute concentration builds up water, can make toxigenic diarrhea
11
Q
NKCC1 stands for
A
NA-K-2Cl transporter
12
Q
in the small and large intestine what is the major apical chloride channel
A
CFTR
13
Q
what does CFTR stand for
A
Cystic fibrosis transmembrane conductance regulator
14
Q
what is the purpose of NACC1?
A
pulls more chloride into cell to make it no longer at equilibrium so that chloride can flow passively out of cell via the apical chloride channels
15
Q
draw out a cell with intestinal chloride secretion and the chloride channels, as well as bacteria’s role
A
pg 9
16
Q
pancreas has both ____ and ____ functions
A
exocrine and endocrine
17
Q
exocrine pancreas secretions are essential for what
A
neutralize gastric acid and digest nutrients
18
Q
describe the secretion of exocrine pancreas
A
very aqueous, lots of HCO3-, enzymatic component
19
Q
what is the purpose of the enzymatic portion of exocrine pancreas secretion
A
digest carbohydrates, proteins, and lipids into absorbable molecules
20
Q
what is an acinus
A
blind end of a branching duct system
21
Q
exocrine pancreas has acinus, what kind of cells are in it
A
acinar cells
22
Q
ducts of exocrine pancreas are lined with what cells
A
ductal epithelial cells
23
Q
what does endocrine pancreas secrete
A
insulin & glucagon
24
Q
centroacinar and ductal cells in exocrine pancreas secrete
A
aqueous HCO3-
25
enzymes from exocrine pancreas are secreted by what cells
acinar cells
26
describe how aqueous component of exocrine pancreas is made/secreted
secreted by centroacinar cells and modified by ductal cells
27
where are the enzymes stored in pancreas until a stimulus tells them to be released
in zymogen granules
28
what are the five major pancreatic proteases that are secreted as inactive precursors
trypsinogen, chymotrypsinogen, proelastase, procarboxypeptidase A, and procarboxypeptidase B
29
enterokinase is what kind of enzyme
brush border
30
what activates trypsinogen into active form trypsin
enterokinase
31
draw out the activation of trypsinogen and all the enzymes it makes active
pg 17
32
what do active proteases cleaved by trypsin hydrolyze
dietary proteins
33
active proteases hydrolyze dietary proteins into
amino acids, dipeptides, tripeptides, and oligopeptides
34
out of the amino acids, dipeptides, tripeptides, and oligopeptides that the protease hyrolyzes, what are absorbable?
amino acids, dipeptides, and tripeptides
35
what happens to oligopeptides since they are not absorbable
further hydrolyzed by brush border peptides
36
after the pancreatic proteases have digested the proteins, what do they do
digest themselves and each other
37
what is the tonicity of pancreatic juice
isotonic
38
what salts/ions are in pancreatic aqueous juice
Na+
Cl-
K+
HCO3-
39
where is the Cl- HCO3- exchanger of ductal cells
apical (lumen side)
40
where is the NA+ K+ ATPase exchanger of ductal cells
basolateral membrane
41
where is the Na+ H+ exchanger of ductal cells
basolateral membrane
42
draw out the exchangers in ductal cell
pg 18
43
what is the net result of ductal cell in pancreas
secretion of HCO3-
| absorption of H+
44
pancreatic venous blood, describe it's properites and why
it is acidic b/c it accepts the H+ that is absorbed by ductal cell
45
when flow rate changes, what ion concentrations remain the same in pancreas
Na+
| K+
46
when flow rate changes, what ion concentratoins change in pancreas
HCO3-
| Cl-
47
at highest pancreatic flow rates, describe concentration of HCO3-
it is at it's highest
48
at highest pancreatic flow rate, describe concentration of Cl-
lowest
49
at low pancreatic flow rate, describe concentration of HCO3-
low
50
at low pancreatic flow rate, describe concentration of Cl-
high
51
what are the two functions of pancreatic secretion
to secrete the enzymes necessary for digestion of carbohydrates, proteins, and lipids and
(2) to neutralize H+ in the chyme delivered to the duodenum from the stomach.
52
aqueous secretion is stimulated by
arrival of H+ in duodenum
53
enzymatic secretion is stimulated by
products of digestion - small peptides, AA, fatty acids
54
what is the function of the enzymatic secretion
secretes enzymes necessary for digestion for carbohydrates, proteins and lipids
55
what is the function of the aqueous secretion
containing HCO3- neutralizes H+ in chyme delivered to duodenum
56
what does secretin do to pancreatic fluid
causes secretion
57
what does CCK do to pancreatic fluid
causes secretion of enzymes
58
what are the three phases of pancreatic secretion
cephalic
gastric
intestinal
59
what is stimulus for cephalic phase of pancreatic secretion
thought of food, smell, taste, chewing, swallowing
60
what is mediator for cephalic phase of pancreatic secretion
ACh and gastrin release via vagus stimulation
61
what is the pancreatic response to cephalic phase
secretion, but especially enzymatic component
62
what is the stimulus of gastric phase of pancreatic secretion
protein in food
| gastric distension
63
what are the mediators of the gastric phase of pancreatic secretion
gastrin
| ACh
64
what is the pancreatic response to gastric phase
increased secretion, but especially enzymatic component
65
intestinal phase accounts for what percentage of pancreatic secretion
80%
66
what is stimulus of intestinal phase of pancreatic secretion
digestion products & H+
67
what kind of receptors do pancreatic acinar cells have
muscarinic receptors
68
muscarinic receptors of pancreatic acinar cells allow what to bind
ACh
69
what is the most important stimulant for enzymatic secretion during intestinal phase
CCK
70
what cells secrete CCK
I cells
71
pancreatic ductal cells have receptors for what
CCK, ACh, and secretin.
72
what cell secretes secretin
S cell
73
what is the major stimulant of aqueous HCO3- pancreatic secretion
secretin
74
what is nature's antacid
secretin
75
what nerve mediates the gastric phase of pancreatic secretion
vagal nerve - vagovagal reflex
76
draw out the cephalic and gastric phase
pg 25
77
draw out the intestinal phase secretion
pg 26
78
what are the main functions of the liver
Processing of absorbed substances
Synthesis and secretion of bile acids
Bilirubin production and excretion
Participation in metabolism of key nutrients (carbohydrates, proteins, and lipids)
Detoxification and excretion of waste products
79
the common bile duct terminates at the
sphincter of oddi
80
where does the sphincter of oddi open
duodenal opening
81
what is bile needed for
digestion and absorption of lipid in SI
82
what is bile made of
bile salts, cholesterol, phospholipids, bile pigments, ions, and water
83
bile is produced and secreted by the
liver
84
bile is stored in the
gall bladder
85
where is bile ejected to
lumen of small intestine
86
bile salts emulsify lipids into packets called
micelles
87
what are the components of the biliary system
liver, gallbladder and bile duct, duodenum, ileum, and portal circulation
88
the gall bladder stores bile and does what else to it
concentrates it
89
what does CCK do to biliary system
stimulates contraction of gall bladder & relaxation of sphincter of oddi
90
when lipid absorption is complete what happens to bile salts
recircultaed to liver via enterohepatic circulation
91
what is the purpose of bile being recirulated to liver
liver doesn't have to produce a ton of new bile
92
draw out the flow of bile
pg 37
93
what happens regarding bile in people who have had ileal resection
recirculation of bile salts to liver is interrupted and large amounts of bile salts are excreted in feces
94
what is ultiamate result of people who have had ileal resection
impaired absorption of dietary lipids and steatorrhea (fat in stool).
95
can liver keep producing enough bile in pts who have had ileal resection
no :(
96
what cell secretes bile
hepatocytes
97
hepatocytes synthesize what two primary bile acids
cholic acid and chenodeoxycholic acid.
98
when primary bile acids are secreted into lumen of intestine, what happens to them
a portion of them are dehydroxylated by bacteria to produce secondary bile acids
99
what are the two secondary bile acids
deoxycholic acid and lithocholic acid.
100
what is the bile salt pool
includes bile salts in the liver, bile ducts, gallbladder, and intestine
101
what amino acids are used to make bile salts
glycine or taurine
102
how does liver make bile salt
conjugates the bile acids with the amino acids glycine or taurine
103
what is the function of creating the bile salts
1.emulsify
| 2 solubulize dietary lipids (they are very water soluble) -
104
what is the critical property of bile salts
amphipathic
105
what doe amphipathic mean
have hydrophilic and hydrophobic part
106
surface of micelle is lined with
bile salts
107
phospholipid property
amphipathic
108
what is function of phoshpolipid being secreted in bile
helps bile salts form micelle
109
what is the major bile pigment
bilirubin
110
cells of what system degrade hemoglobin to make bilirubin
reticuloendothelial
111
how is bilirubin carried in blood
bound to albumin
112
liver extracts bilirubin in blood and does what with it
conjugates it with glucuronic acid
113
when liver conjugates bilirubin with glucuronic acid what does it form
bilirubin glucuronide
114
what accounts for biles yellow color
bilirubin glucuronide
115
what is steatorrhea
fat in stool
116
bile is made up of 50%
bile salts
117
draw out cholsterol into primary and then secondary bile acids
pg 40
118
draw out bilirubin metabolism
pg 43
119
in the intestine, bilirubin glucorunide is turned into
back to bilirubin
120
what does secretin do to bile ducts
stimulates ion and water secretion
121
what are the three functions of the gall bladder
store bile
concentrates bile
ejects bile
122
compare hepatic bile vs. gallbladder bile
include percentage of solids
bile salts
pH
pg 47
123
what is the major stimulus for ejection of bile
CCK
124
what is the effect of CCK on gall bladder
relaxation of sphicnter of oddi
| contraction of gall baldder
125
how is bile ejected from gall bladder
spurts, not a steady stream
126
how does duodenum contracts effect bile ejection from gall bladder
when duodenum is contracted pressure is too high and gall bladder cannot eject
when duodenum is relaxed, bile is ejected
127
what are the two types of gall stones
cholesterol stones
| pigment stones
128
how do cholesterol stones form
obeses pts: too much cholesterol.
other pts; phospholipids and bile salts too low
too much cholesterol → crystals
129
pigments stones are made from
precipitates (solids) of unconjugated:
| biliribuin with calcium
130
what is cholestasis
decreased bile flow
131
if stones get stuck in bile duct what happens
decreased bile flow and jaundice
132
what are the causes of gall stones
too much absorption of water from bile
too much absorption of bile acids from bile
too much cholesterol
inflammation of epithelium
133
enterokinase is released from
intestinal epithelial cells
134
pancreatic juice is an isotonic solution containing
```
Na+
Cl-
K+
HCO3-
enzymes
```
135
chloride bicarb exchanger is stimulated when
when you have a meal
136
chloride bicarb exchanger does what
brings chloride in, secretes bicarb into lumen of ductal area
137
why is sodium potassium pump on basolateral side
sodium comes through secondary active transport mechanisms and then sodium builds up its electrical chemical gradient and has to be pumped to basolateral side (?)
138
the only major transporter in apical membrane of epithelial cell that modifies pancreatic juice
chloride bicarb exchanger
139
why doesn't sodium and potassium change their concentrations if eat or fast
they don't have exchangers to make a difference in their levels
140
what hormone stimulates bicarb secretion
secretin
141
gastric phase for pancreatic secretion is not
a major phase
142
what are the main phases for pancreatic secretion
cephalic & intestinal
143
what cells release secretin
S cells
144
where are S cells
intestines
145
what cells release CCK
I cells
146
where are I cells
intestine
147
cck acts on acinar cells to release
enzyme
148
cck acts on vagus nerve and stimulates
vagovago reflex - which will go to acinar cells
149
gastrin release is mostly in
dogs
150
hydrogen stimulates what cells in intestinal phase
S cells
151
if there's a problem in duodenum there will be problem with secretion in
CCK
| secretin
152
where is pepsinogen released?
chief cells in stomach
153
how are acinar cells simtulated, what pathway
PLC
154
bile acids are _____ soluble
lipid
155
every time there is contraction what happens to pressure in duodenum
it goes up, which is greater than gall bladder so stops it from leaving gall bladder
