GI Physiology: Pancreas Flashcards

1
Q

Name a congenital disease that results in pancreatic insufficiency.

A

CF

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2
Q

The majority (85%) of the pancreas is involved in ________.

A

digestion

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3
Q

Which pancreatic enzymes are released in inactive form? Why is this?

A

All the proteolytic enzymes are - because they are potent (especially trypsin - it activates all the others)

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4
Q

What is responsible for the bulk of protein digestion? Where does this occur?

A

Pancreatic proteases in the proximal small intestine.

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5
Q

What enzyme is primarily responsible for activation of trypsinogen –> trypsin? Where exactly is this enzyme found?

A

Enterokinase - it is a membrane-bound enzyme found in the proximal small intestine.

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6
Q

Which pancreatic enzyme can convert all the other pancreatic proteases to their active forms?

A

Trypsin

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7
Q

What is the point of releasing trypsin inhibitor along with trypsinogen?

A

To protect against any small amounts of premature trypsinogen –> trypsin activation.

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8
Q

Pancreatic lipase cleaves TAGs into ______ and ______.

A

2-MAGs and FFAs

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9
Q

Can vertebrates digest cellulose?

A

Nope

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10
Q

Which phase of digestion is responsible for the majority of the stimulation of pancreatic secretion?

A

Intestinal!

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11
Q

Which hormones/substances stimulate pancreatic ductal cells and which ones stimulate pancreatic acinar cells?

A

CCK and Ach (from vagus nerve) stimualtes ACINAR cells to release enzymes.

Secretin stimulates DUCTAL cells to make bicarbonate and fluid.

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12
Q

What stimulates “i” cells in the small intestine to release CCK into the bloodstream?

A
  1. AAs/peptides
  2. Fatty acids
  3. H+ in the duodenum

1 and 2 mostly

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13
Q

What stimulates “s” cells in the small intestine to release secretin into the bloodstream?

A

Fatty acids and H+ (duodenal acid load)

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14
Q

Describe how the concentrations of HCO3- and Cl- change as pancreatic secretory rate increases. Explain why.

A

HCO3- concentration increases and Cl- decreases because the ductal cells use a HCO3-/Cl- exchanger and ductal cell stimulation results in a large increase in bicarb and fluid secretion.

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15
Q

Why does the concentration of amylase decrease upon pancreatic secretion?

A

Because the increase in fluid secretion upon stimulation of ductal cells outweighs the corresponding increase of enzyme secretion by acinar cells, so amylase is diluted.

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16
Q

Amino acids/peptides stimulate only two of three mechanisms that go on to stimulate the pancreas. Name them.

A

They upregulate the vago-vagal reflex and i cells’ secretion of CCK.

They do NOT work on s cells (secretin)

17
Q

What mechanisms of pancreatic secretion are upregulated by fatty acids and duodenal acid load?

A

All three (vago-vagal, CCK release, and secretin release)

18
Q

Which duodenal food product cannot stimulate secretin release?

A

AA’s/proteins