(39) - Gastric Secretion

Question 1

look at this

Question 2

1-6. What are the six cell types involved in gastric secretion?

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Answer 2

1. Mast cells
2. parietal (oxyntic) cells
3. mucous cells
4. endocrine cells
5. chief cells
6. epithelial cells

Question 3

(Say what each cell releases - plus more)

1. parietal (oxyntic) cells
2. chief cells
3. mucous cells
4. endocrine cells
5. mast cells
6. epithelial cells

Answer 3

1. protons, intrinsic factor
2. pepsinogen (inactivated form of pepsin - protein digestion)
3. sulfated glycoproteins (mucous) (part of gastric barrier)
4. gastrin (hormone - taken up by ciculation - binds to gastrin receptor on parietal cell to stimulate acid secretion)
5. histamine (bind to histamine H2 recepotors on parietal cells - stimulating these cells to secrete protons) (paracrine effect)
6. HCO3-, prostanoids (prostaglandins - inflammation - but these are beneficial)

(ACTH from neurons also bind to parietal cells and releases acid - third mechanism!)

Question 4

(functions of gastric secretion)

1. there are five - name them…

PIIIP

Answer 4

1. protein digestion - acid (H+) and pepsin
2. inactivation of bacteria, viruses, and parasites
3. iron absorption - Fe2+ + H+ <–> Fe3+
4. intrinsic factor –> cobalamin absorption
5. prostanoids –> mucosal barrier cyto-protection

Question 5

(Phases of Gastric Secretion)

1. occurs in the absence of all cephalic, gastric, and intestinal stimulation
2. mediated by sight, smell, taste, swallowing
3. mediated by gastric diestension and protein
4. mediated by duodenal (amino acid)

Answer 5

1. basal phase
2. cephalic phase
3. gastric phase
4. intestinal phase

Question 6

key points - just get a feel for this

also remember that in this matric there are a number of mast cells with a paracrine effect on parietal cells

Question 7

amino acids of peptides that are directly stimulatign parietal cells

second important stimulus during this phase = ditension

Question 8

(The gastric parietal cell)

1-3 What are the three major receptors for what three substances?

4. What is the key inhibitor of acid secretion?

Answer 8

1. histamine (paracrine)
2. acetylcholine
3. gastrin (endocrine)

(get a feel for this graph too)

(the pathways especially)

4. prostanoid/prostaglandin (mediated by PGE2)

Question 9

(Gastric Intrinsic Factor - Vitamin B12 binding)

1. just watch this - sorry
   38: 00 3/6/13

also the next slide

Question 10

Seven Different Mechanisms for Inhibiting gastric acid secretion

just learn this

Question 11

(What are the five componenets of gastric mucosal barrier)

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Answer 11

1. mucosal cell renewal
2. prostaglandins
3. mucous secretion
4. mucosal blood flow
5. HCO3- secretion