Monogastric pt 5

Question 1

What are the cells in the gastric glands?

Answer 1

• Surface epithelial cells
• Mucous neck cells
• Parietal
• Stem
• Chief
• Endocrine cells

Question 2

What do surface epithelial cells do?

Answer 2

Secrete mucous and HCO3 protective function

Question 3

What do mucous neck cells do?

Answer 3

Secrete thin mucous, cell division

Question 4

What do parietal cells do?

Answer 4

HCl secretion, intrinsic factor secretion for vitamin B12 absorption

Question 5

What do chief cells do?

Answer 5

Pepsinogen secretion

Question 6

What do endocrine cells do?

Answer 6

Secrete regulatory substances (somatostatin, gastrin, histamine)

Question 7

What are the glands in the cardia?

Answer 7

• Secrete only mucous
• Alkaline
• Protective function

Question 8

What are in the glands in the antrum?

Answer 8

No parietal

• D cells (somatostatin)
• G cells (gastrin)
• Chief cells

Question 9

What kind of secretion is HCl?

Answer 9

Isotonic for protective and protein denaturation and optimization of pH for proteolysis

Question 10

How is H extrused?

Answer 10

Through H/K ATPase where K is recycled

Question 11

How is HCO3 reabsorbed?

Answer 11

Not significant if healthy through and can cause an alkaline tide

Question 12

What blocks the H/K ATPase blocker?

Answer 12

Omeprazole

Question 13

What causes gastrin secretion and what is the source?

Answer 13

G cells and ACh

Question 14

What causes histamine secretion and what is the source?

Answer 14

ECL, mast cells; gastrin, ACh

Question 15

What causes ACh secreted and what is the source?

Answer 15

Vagus, ENS

Question 16

What do Gastrin, histamine, and Ach stimulate?

Answer 16

H/K ATPase on the luminal side

Question 17

What inhibits the H2 receptor (histamine receptor)?

Answer 17

Ranitidine, cimetidine

Aren’t as effective as omeprazol

Question 18

What does somatostatin do?

Answer 18

Inhibit histamine stimulated HCl secretion. Either by blocking the release of histamine from parietal cells or by inhibiting adenylate cyclase.
Inhibit HCl through G cell release

Question 19

What is pepsinogen?

Answer 19

Zymogen that is released and cleaved and activated by low pH to make pepsin, positive feedback where pepsin cuts up more pepsinogen

Question 20

What activates pepsinogen release?

Answer 20

• ACh
• Peptide hormones
• Beta adrenergic component

Question 21

What happens when luminal pH gets too low?

Answer 21

Gastrin secretion ceases so less pepsinogen and HCl

Question 22

What are the phases of gastric acid secretion?

Answer 22

• Basal-no secretion
• Cephalic-30% acid secretion
• Gastric-Most acid secretion
• Intestinal

Question 23

What happens during the cephalic phase?

Answer 23

Vagal input causes ACh release which binds to parietal cells and causes gastrin release

Question 24

What happens during the gastric phase?

Answer 24

Presence of food in the stomach causes distension sensed by stretch receptors and ACh gets secreted. This stimulates G cells (low pH eventually turns these off) and Parietal cells and you get HCl secretion

Question 25

What buffers the pH of the lumen?

Answer 25

Food in the lumen. This relieves inhibition of G cells by low pH and sustains gastrin and HCl secretion

Question 26

What is the effect of NSAIDs on HCl?

Answer 26

This blocks COX1 and 2 which lowers PGE secretion. This causes an increase in parietal cell acid secretion

Question 27

What are the exocrine pancreas secretions?

Answer 27

- Digestive enzymes - Electrolytes - HCO3

Question 28

What are the secretions of the liver?

Answer 28

- Bile | - Electrolytes (HCO3)

Question 29

What type of enzymes are released from acinar cells?

Answer 29

Zymogens that get released into duodenal lumen and activated after cleavage

Question 30

What type of enzymes released from pancreatic acinar cells are there?

Answer 30

- Lipid breakdown - Nucleic acid breakdown - Protein breakdown

Question 31

What is the pH of pancreatic juice and why is it important?

Answer 31

High 8.1 due to HCO3 concentration; Neutralizes luminal acidity and is optimal for enzyme function and micellar solubilization

Question 32

What regulates HCO3 secretion?

Answer 32

-ACH -CCK -Secretin -VIP All stimulate the acinus. ACh and secretin stimulate the duct

Question 33

What is the primary hormone for acinar secretion?

Answer 33

CCK

Question 34

What is the main hormone for ductal secretion?

Answer 34

Secretin

Question 35

What makes up the epithelial cells of the liver?

Answer 35

Hepatocytes

Question 36

What is the origin of bile?

Answer 36

Cholesterol (nonsoluble) with bile acids (partially soluble)

Question 37

What is the purpose of bile?

Answer 37

Emulsification of dietary lipids

Question 38

Where is bile stored?

Answer 38

Gallbladder

Question 39

When are bile acids released?

Answer 39

When sphincter of Oddi opens when food is in the lumen and CCK regulation. Released into the duodenum and reabsorbed in the ileum where it recirculates to the liver through the portal vein

Question 40

What happens in species that do not have a gallbladder?

Answer 40

Bile is continuously released (horse, rat)