Overview and GI function Physiology - Prunuske

Question 1

Scientific term for stomach rumbles?

Answer 1

Borborygmi

Question 2

What do you call the food in your stomach once it has been squeezed into the duodenum?

Answer 2

chyme

Question 3

What is sitophobia?

Answer 3

Fear of eating

Question 4

Diverticulosis caused by:

Answer 4

Low fiber diet

Question 5

What protects the protein core of mucin from being broken down by proteases?

Answer 5

Glycosylation protects them

Question 6

Vitamine b12 (cobalamine is absorbed in what protion fo the small intestine?

Answer 6

The ileum

Question 7

What does the liver secrete in order to facilitate lipid absorption?

Answer 7

bile salts

Question 8

A patient with a recent bowel resection of the ileum is concerned about some very foul-smelling and oily bowel movements recently.
What is the condition?
What is causing it?

Answer 8

Steatorrhea (or fatty stools)

You need bile salts in order to emulsify lipids from the diet. It turns out 95% of bile salts are recycled when the are reabsorbed in the ileum. If this patient is missing ileum then they are going to be running out of bile salts fast. Hence that fatty stools

Question 9

A patient of your with known hyper coagulability from cancer effects has presented at the urgent care with lower abdominal pain after eating, bloody diarrhea, and has lacked desire to eat anything the last 2 days.

Answer 9

Could be: Mesenteric ischemia

• possibly caused by thrombi in the mesenteric veins
• areas of the small intestine become necrotic without oxygen, causing these symptoms

Question 10

What causes osmotic diarrhea?

Answer 10

Microbial overgrowth in bowel leads to increased production of organic acids, pulling water from the blood into the gut lumen

Question 11

How long does food spend in the:
stomach
small intestine
large intestine

Answer 11

stomach: 4-5 hrs
small intestine: 2.5-3 hrs
large intestine: 30-40 hrs

Question 12

How does pressure on the distal and proximal ends of a gut sphincter affect relaxation and contration?

Answer 12

Sphincter
proximal pressure = relaxation
distal pressure = contraction

This makes sense if you want them to be a one way valve!

Question 13

What will releasing a lot of extra calcium will do to the muscle contraction in the intestine?

Answer 13

Amplitude will increase, but frequency will stay the same!

Question 14

What does the hormone motilin control?

Answer 14

The migrating motor complex!

Relaxes sphincters and contracts stomach and small intestine in fasting
Moves everything through quick. (responsible for those stomach rumbles we get)

Question 15

efferent motorneurons are located in the myenteric plexus

Excitatory fibers release:
Inhibitory fibers release:

Answer 15

Excitatory: ACh, Neurokinin A, Substance P

Inhibitory: VIP and NO

Question 16

How do parasympathetic and sympathetic nervous systems affect the Gi tract?

Answer 16

Parasympathetic: Increase GI motility and secretory activity

Sympathetic: Decrease GI motility, contracts sphincters, constricts GI microvasculature

Question 17

What does gastrin do?

Where is it released from?

Answer 17

G cells in the stomach antrum detect amino acids and then release gastrin. Gastrin stimulates the secretion of gastric acid (HCl) from parietal cells of the stomach and pepsinogen from chief cells.

Keep in mind that HCl release is stimulated directly on parietal cells and indirectly by binding on CCK/gastrin receptors on ECL cells. ECL cells release histamine which then act on parietal cells.

Question 18

What is Cholecystokinin (CCK) ?

Where does it come from?

Answer 18

I cells in the Duodenum and Jejunum secrete CCK after they detect fat and amino acids in the lumen.

CCK stimulates release of bile salts and digestive enzymes from the pancreas and gall bladder involved in fat uptake.

Question 19

What produces secretin?

What does it do?

Answer 19

S cells in the duodenum and Jejunum crypts release secretin in response to acid.

Secretin causes pancreatic cells to release a bicarbonate solution and inhibits gastric motility.

Question 20

Gastric Inhibitory Peptide (GIP).

What is it? Where’s it from? What is it’s deal?

Answer 20

Secreted by K cells in the duodenum/Jejunum when they detect lots of glucose.

GIP stimulates insulin release

(Ppt actually has outdated info on it… this is what I found on wikipedia)

Question 21

What is motilin? Where is it secreted? what does it do?

Answer 21

Secreted by endocrine cells.

It is released cyclically during the fasting state to initiate the migrating motor complex