Goal 6 (g-m): Physiology Of The Stomach

Question 1

What are the 7 functions of the stomach?

Answer 1

• mechanical
• digestive
• absorptive
• excretory
• stimulatory
• reflex
• antiseptic: with HCL

Question 2

Where is the Oxyntic gland location? Where is the pyloric gland located?

Answer 2

• Oxyntic: fundus and body of the stomach

- pyloric: pyloric and antrum area of the stomach

Question 3

What cells produce basal electrical rhythm and are also called the pacemakers of the GI tract? Where are they located?

Answer 3

• Interstitial cells of Cajal

- myenteric plexus to ileum, and see a lot in the large intestine

Question 4

What are the rate of slow waves in: stomach, duodenum, distal ileum, carcinoma, and sigmoid?

Answer 4

• Stomach: 4 waves/min
• duodenum: 12
• distal ileum: 8
• caecum: 9
• sigmoid: 6

Question 5

How does epinephrine affect motility?

Answer 5

Decrease motility

Question 6

What types of motility are involved in the fasting state? What types of motility are involved when eating a meal?

Answer 6

• fasting: migrating motor complex (MMC) and hunger contractions
• meal: receptive relaxation, mixing peristalsis waves, gastric emptying

Question 7

What are the “interdigestive housekeepers of the gut?”

Answer 7

MMC

Question 8

What inhibits MMC? After how much time after a meal will you see it? What is a big function of it? What happens if that function is abolished?

Answer 8

• eating a meal inhibits it
• 90-120mim after meal is when you see it
• sweeps leftovers, remove extra artifacts in stomach that was left over from the liquification
• don’t sweep out extra food by MMC, it stays in stomach and bacteria growth increases, leading to infections

Question 9

What are hunger contractions (mild peristalsis waves)? What causes it? What are tetanic contractions?

Answer 9

• MMC turn into these
• after a period of hours of having an empty stomach, these are stomach growling you have
• these are when many mild peristalsis waves fuse to make a large wave—are hunger pains you have when you don’t eat for a long time

Question 10

What is receptive relaxation? How much food can an empty stomach take in (ml)? What can it accommodate though? What allow this accommodation?

Answer 10

• a relaxation period seems after a meal where stomach accommodates as food enters
• 50ml
• 2-3L
• VIP and NO

WHOLE THING CALLED VAGOVAGAL REFLEX

Question 11

What are the steps of receptive relaxation?

Answer 11

• 1: food hits myenteric receptors and stretch the gastric mucosa
• 2: the stretch stimulates the vagus nerve and sends an afferent signal to CNS (medulla)
• 3: then from CNS, vagus nerve sends an efferent signal back and synapses to the mesenteric plexus (preganglionic fiber) and released Ach
• 4: Ach attaches to the post ganglionic fiber on the stomach and release NO and VIP

Question 12

When does receptive relaxation start?

Answer 12

The minute food touched the GASTRIC MUCOSA

Question 13

What does CCK do?

Answer 13

• increases relaxation

- I cells in duodenum release it to do more vagovagal reflex

Question 14

What nerve needs to be intact to do receptive relaxation? If this is damaged, what other function of the GI tract can be affected?

Answer 14

• VAGUS NERVE

- need vagal nerve for primary esophageal peristalsis where deglutition happens so will have SWALLOWING ISSUES

Question 15

What is a Vagotomy? Why is this a last resort procedure?

Answer 15

• removal of vagus nerve for gastric and peptic ulcer patients if no other treatment works
• you lose receptive relaxation (stomach can accommodate less food than normal) and have swallowing problems