GM Week 2

Question 1

How does peristalsis work?

Answer 1

Sensory neurons activated by pH and distention of intestine stimulate interneurons in the myenteric plexus, which in turn stimulate excitatory neurons on either side of the food bolus. On the oral side, ACh causes constriction of smooth muscle. On the caudal side, NO and VIP (vasoactive intestinal peptide) cause relaxation of smooth muscle.

Question 2

What part of the world is Chagas Disease common in?

Answer 2

Mexico, Central and South America

Question 3

Which part of the nervous system is NOT affected by Chagas disease?

Answer 3

Sympathetic

Question 4

What is the treatment for Chagas disease in the chronic phase?

Answer 4

There isn’t one

Question 5

What causes Chagas disease?

Answer 5

Trypanosoma cruzi parasite, transmitted by insect vector Triatomine

Question 6

SSx of Chagas disease:

Answer 6

• Acute: swelling of eyelid at site of infection

- Chronic: enlarged heart, esophagus or colon. Difficulty eating or passing stool.

Question 7

What do the interstitial cells of Cajal do?

Answer 7

• Provide pacemaker activity to the enteric nervous system.

- Slow wave depolarization

Question 8

If a patient continues to have diarrhea after fasting for a day or so, what type of diarrhea are they likely to have?

Answer 8

Secretory

Question 9

What type of diarrhea is cholera?

Answer 9

Secretory

Question 10

How does scleroderma lead to esophageal reflux?

Answer 10

Esophageal dysmotility is very common in scleroderma. The LES becomes incompetent and aperistalsis prevents refluxed stomach contents from being pushed back into the stomach. This leads to destruction of esophagus.

Question 11

Distinguishing features of Crohn’s vs. ulcerative colitis:

Answer 11

Crohn’s:

• Skip lesions
• Non-caseating granulomas
• Rectum can be spared

Question 12

True or false: anticholinergics are contraindicated for acute diarrhea.

Answer 12

True due to risk of toxic megacolon.