Littleton Part III

Question 1

Acid secretion is influenced by what?

Answer 1

pH, food buffering, and gastric emptying

Question 2

What happens to food buffers during food ingestion and after eating?

Answer 2

During ingestion there is peak in food buffers in the stomach and hours after eating it decreases

Question 3

What happens to the rate of hydrogen secretion during ingestion and after?

Answer 3

during ingestion it does not increase.

1 hour after ingestion it increases and then maxes out after 2 hours due to the release of somatostatin. Somatostatin causes it to decrease.

Don’t forget rate of H+ secretion is done by the parietal cells

Question 4

What happens to the concentration of hydrogen ions during ingestion of food and after?

Answer 4

Hydrogen concetration decrease during ingestion of food. After two hours the concentration of Hydrogen ions increases and continues to increases.

Question 5

When does the stomach have the lowest level of acid?

Answer 5

1-2 hours after a meal

Question 6

Pancreatic secretions are stimulated by what?

Answer 6

Neural and humoral mechanism

Question 7

The major stimulus for acini secretion is?

Answer 7

CCK (humoral)

acini cells have receptors for Ach (neural), M3, GRP (neural), and VIP (neural)

Question 8

Acini cells secrete what?

Answer 8

digestive enzymes

Question 9

What is the stimulus for pancreatic duct secretion?

Answer 9

Secretin (humoral)

Question 10

What do pancreatic duct cells secrete?

Answer 10

Na HCO3, H20

Question 11

Pancreatic duct cells have receptors for?

Answer 11

Ach (neural)

secretin (humoral)

Question 12

In the duct lumen if you have a high rate of pancreatic juices what are your levels of bicarb and Cl-?

Answer 12

More bicarb

less chloride

Question 13

In the duct lumen if you have a low rate of pancreatic juices what are your levels of bicarb and Cl-?

Answer 13

More Chloride

less bicarb

Question 14

Are pancreatic secretions alkaline or acidic during the intestinal phase of the meal?

Answer 14

Alkaline

Secretion of bicarb increases and chloride secretion decreases. This causes a increase in pH.

(potassium unchanged)

Question 15

Pancreatic acinar cells secrete many different proteins, what are there categories?

Answer 15

Proteases

Amyolytic enzyme

Lipases

Nucleases

and there is a others categories

Question 16

Examples of proteases secreted by pancreatic acinar cells?

Answer 16

trypsinogen

chymotrypsinogen

proelastase

procarboxypeptidase A

procarboxypeptidase B

Question 17

Examples of amyolytic enzymes?

Answer 17

amylase

Question 18

Examples of lipases?

Answer 18

lipase

lipase-related proteins

prophospholipase A1, A2

nonspecific esterase

Question 19

Examples of nucleases?

Answer 19

deoxyribonucleases

ribonucleases

Question 20

What are the enzymes listed in the others catagories for enzymes secreted by the pancreatic acinar cells?

Answer 20

procolipase

trypsin inhibitors

monitor peptide

Question 21

Contraction of the gallbladder and sphincter of oddi relaxation by both neural and humoral pathways is stimulated by what?

Answer 21

CCK

CCK is released by the small intestine -> vagal afferent seignal to DVC -> vagal efferent signal sent to gall bladder (acts on Ach) and sphincter of Oddi (act on VIP/NO)

Question 22

In some people the common bile duct fuses with main pancreatic duct instead of sphincter of oddi. If you get a gallstone what can this lead to?

Answer 22

It prevents pancrease from releasing enzymes

Question 23

Pancreatic polypeptide is a feedback modulator of _____ ________ to the pancrease

Answer 23

Vagal efferents