2 Secretions of the GI Tract and Pancreas Flashcards
1
Q
The parotid gland contains what types of cells
A
Serous
2
Q
What are the main cell types of the submandibular and sublingual glands
A
Mixed mucous and serous
3
Q
What are the cells which produce the initial saliva
A
Acinar
4
Q
What cells modify the saliva to make it hypotonic
A
Striated duct (columnar epithelial)
5
Q
What type of cells contract to eject saliva
A
Contractile (myoepithelial) cells
6
Q
What is in saliva
A
- water
- electrolytes
- α amylase
- lingual lipase
- kallikrein
- mucus
7
Q
What is kallikrein
A
Precursor to bradykinin which causes vasodilation
8
Q
How does saliva compare to plasma
A
Saliva has more K and HCO3
Saliva has less Na and Cl
9
Q
What is the overall effect of saliva on ions
A
Absorption of Na and Cl
Secretion of K and HCO3
10
Q
What does parasympathetic do at salivary glands
A
Originates in facial and glossopharyngeal nn and they use mAChR
11
Q
Where do the sympathetic controls originate
A
T1-3 and superior cervical region and they wrap around arteries
12
Q
What do parasympathetic do for salivary glands? Sympathetic?
A
Both increase secretions
13
Q
What factors increase saliva
A
- conditioning
- food
- nausea
- smell
14
Q
What decreases saliva
A
- dehydration
- fear
- sleep
- fatigue
15
Q
What is downstream of the parasympathetic muscarinic receptor in the salivary glands
A
IP3 and Ca
16
Q
What is down stream of the sympathetic β receptor on the salivary gland
A
cAMP
17
Q
What do parietal cells produce
A
HCl and IF
18
Q
Where are parietal cells mainly found
A
Body of stomach
19
Q
What do chief cells produce
A
Pepsinogen
20
Q
Where are chief cells mainly found
A
Body of stomach
21
Q
What do G cells produce
A
Gastrin
22
Q
Where are G cells mainly found
A
Antrum of stomach
23
Q
Where are mucous cells mainly found
A
Antrum
24
Q
Glands of the stomach are divided into what categories
A
Oxyntic and pyloric
25
What are the characteristics of oxyntic gland
- located in proximal stomach (body and fundus)
- parietal cells that secrete acid
- D cells, mucous cells, ECF cells, chief cells
26
What are the characteristics of pyloric glands
- located in distal 20% of stomach
- G cells that secrete and synthesize gastrin
- D cells, mucous cells, ECF cells
27
What do D cells produce
somatostatin
28
When the stomach is removed you are at risk for vitamin deficiencies in what vitamins
Fat soluble vitamins
29
What do parietal cells do
Secrete HCl
30
Where is HCl formed in parietal cells
Canaliculi
31
What is the alkaline tide? What cells are responsible
Uptake of HCO3 and secretion of HCl; parietal cells
32
What does the parasympathetic do to G cells
Stimulates gastrin release through GRP directly and inhibits release of somatostatin
33
Increased secretion of gastrin increases secretion of what
Somatostatin
34
What stimulates somatostatin
H in gastric lumen
35
What cells secrete somatostatin
D cells
36
Pepsinogen are secreted by what cells
Chief cells
37
What is the optimal pH for pepsinogen?
1.8-3.5
38
What is the most important stimulus for pepsinogen
Vagus N
39
How does omeprazole decrease acid
Inhibits H/K antiporter
40
How does cimetidine work
Acts on the H2 (histamine) receptor as an antagonist which treats GERD, duodenal and gastric ulcers
41
What do ECL cells secrete
Histamine
42
What are stimulators of the H/K ATPase on the parietal cells
```
M3 receptor (vagus)
CCKb receptor (gastrin)
H2 receptor (histamine)
```
43
What are the main inhibitors for the parietal cells
Somatostatin and prostaglandins
44
What does atropine do in parietal cells
It is a muscarinic blocker which would function to decrease H secretion in parietal cells
45
What are the phases of gastric HCl secretion
Cephalic
Gastric
Intestinal
46
What is the cephalic phase of gastric secretion
- 30% of total HCl secretion
- stimulated by smell, taste, chewing, swallowing, and conditioned reflexes
- works via Vagus N
- Vagus stimulates gastrin which stimulates parietal cells
47
What is the gastric phase of gastric secretion
- 60% of total HCl
| - stimulated by stomach distention and AA
48
Distention of fundus and body of stomach activates what
Mechanoreceptors in mucosa of oxyntic and pyloric activate direct and indirect vagus stimulation
49
What does distention of the antrum do
Local (pyloropyloric) reflex stimulates gastrin release
50
What do AA in the stomach do
Stimulate gastrin release
51
What is the intestinal phase of gastric secretion
- 10% of total HCl
| - stimulated by distention of SI (NS mediated) and presence of digested protein (hormonal regulation)
52
Gastric juice is made of what components
Non-parietal and parietal
53
Failure to secrete what and from what cell results in pernicious anemia
IF from parietal cells
54
Where is Vit B12 absorbed
Ileum
55
What cells are present in the gastric mucosa
Mucous neck cells and gastric epithelial cells (HCO3)
56
What are the protective factors of the gastric mucosa
- HCO3 and mucous
- prostaglandins
- blood flow
- gastrin
- GF
57
What are the damaging factors of the gastric mucosa
- acid
- pepsin
- nsaids
- H. pylori
- EtOH
- bile
- stress
58
Gastrinomas are associated with what
Zollinger-Ellison syndrome
59
Under normal conditions, secretin administration _______ gastrin but does the opposite in gastrinomas
Ihibit
60
Peptic ulcer disease are due to what
Excessive H and pepsin OR loss of protective mucosal membrane
61
What is the primary cause of ulcers
Defective mucosa caused by H pylori
62
What allows H pylori to colonize
Urease
63
What from H pylori causes breakdown of mucosa and underlying cells
Cytotoxin
64
How does H pylori have an affect on duodenal ulcers
- inhibits somatostatin secretion from D cells
| - gastric H pylori infection spreads and inhibits HCO3
65
H secretion rates are a little higher than normal with what
Duodenal ulcers
66
What has the highest rate of H secretion
Zollinger ellision syndrome
67
Where are the gastrinomas often
Pancreas
68
What are the effects of Zollinger Ellison syndrome
- excessive delivery of H to duodenum
| - inactivation of pancreatic lipase due to suboptimal pH
69
How does the pancreas compare to salivary glands
Isotonic secretions
70
What comes from pancreatic acinar cells
Enzymatic secretions
71
What comes from centroacinar and ductal pancreatic cells
Aqueous secretion
72
What is the net result of the pancreas
Secretion of HCO3 and absorption of H
73
What are the 3 phases of pancreatic secretion
Cephalic
- initiated via vagus by smell, taste, and conditioning
- produces mainly enzymatic secretions
Gastric
- initiated via vagus by distention of stomach
- produces mainly enzymatic secretions
Intestinal
- 80% of pancreas secretion
- enzymatic and aqueous secretions stimulated
74
What is the sympathetic innervation of the pancreas
Postganglionic nerves from celiac and superior mesenteric plexuses that are inhibitory
75
What is the parasympathetic innervation of the pancreas
Vagus which is stimulatory
Preganglionic synapse in ENS and post ganglionic synapse on exocrine pancreas
76
I cells produce what
CCK
77
S cells produce
secretin
78
Acinar cells are stimulated by
ACh and CCK
79
What stimulates ductal cells of pancreas
ACh, CCK, secretin
80
Cystic fibrosis transmembrane conductance regulator causes what to fail early
Pancreas, b/c Cl can’t leave cells to come back in and bring HCO3 in
81
What does motilin do?
Produces migrating motor complexes
82
Where does GIP get produced? What does it do
K cells (duodenum, jejunum)
Decrease H secretion
Increase insulin release
83
Where is iron absorbed
duodenum as Fe2
84
What is pleomorphic adenoma
Most common type of salivary gland cancer
85
Which bilirubin is water soluble
Direct; it is conjugated with glucuronic acid
86
Pancreatic insufficiency results in what deficiency
Fat soluble vitamins (ADEK) and B12
87
How is tropical sprue different than celiac
Responds to antibiotics
88
What is whipple disease
Infection with type of bacteria
Foamy macrophages in lamina propria
Cardiac symptoms
Arthralgias
Neurologic symptoms
89
AST and ALT elevated but ALT>AST
Most liver disease
90
Liver enzymes increased and AST>ALT
Alcoholic liver disease
91
Alkaline phosphatase is elevated in
Cholestasis (biliary obstruction), infiltrative disorders, bone disease
92
Gastrin is secreted by what cells
G cells
