Colon Physiology MCQ Quiz | Gastrointestinal System

1. What is the primary physiological function of the colon?

2. The main source of energy for colonocytes is which short-chain fatty acid (SCFA)?

3. The characteristic sacculations of the colon wall are known as:

4. Mass movements in the colon are powerful peristaltic contractions typically initiated by the:

5. Which of the following vitamins are significantly synthesized by the colonic microbiota?

6. The defecation reflex is initiated by the distension of which structure?

7. The internal anal sphincter is composed of involuntary __________ muscle and is tonically __________.

8. Voluntary control over defecation is primarily exerted via the:

9. Which of the following is NOT significantly absorbed in the healthy human colon?

10. The primary secretory product of the colonic epithelium, which serves to lubricate feces and protect the mucosa, is:

11. Parasympathetic innervation to the proximal two-thirds of the colon is primarily provided by which nerve?

12. Fermentation of indigestible carbohydrates by colonic bacteria primarily produces:

13. The “rectoanal inhibitory reflex” (RAIR) describes the:

14. The absorption of sodium in the distal colon is significantly enhanced by which hormone?

15. Which gas, a major component of flatus, is produced in the colon by bacterial metabolism but not by human cells?

16. The teniae coli are three distinct longitudinal bands formed by the thickening of which muscle layer?

17. The primary role of bicarbonate secretion in the colon is to:

18. Compared to the small intestine, the motility of the colon is best described as:

19. Hirschsprung’s disease is a congenital disorder characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the distal colon, leading to:

20. Which of the following ions is actively secreted into the colonic lumen, a process that can be excessive in certain types of diarrhea?

21. The most abundant short-chain fatty acid produced in the colon is:

22. Parasympathetic stimulation of the distal colon via the pelvic splanchnic nerves leads to:

23. Dietary fiber increases stool bulk primarily by:

24. Water absorption in the colon occurs primarily via which mechanism?

25. What is the approximate maximum absorptive capacity of the colon for water per day?