Physiology · GIT Physiology (Secretions, Hormones, Motility, Absorption)

The interstitial cells of Cajal (ICC) in the GI tract function as:

  • A Primary secretomotor neurons controlling enzyme secretion
  • B Pacemaker cells generating slow waves (basic electrical rhythm) that set the maximum frequency of smooth muscle contractions
  • C Sensory cells detecting luminal contents and relaying to the enteric nervous system
  • D Immunological cells that sample luminal antigens for mucosal immune responses
Correct answer: B. Pacemaker cells generating slow waves (basic electrical rhythm) that set the maximum frequency of smooth muscle contractions

Explanation

Interstitial cells of Cajal, located in the myenteric plexus layer and within smooth muscle, express c-kit (CD117) and generate rhythmic slow waves (pacemaker potentials) at characteristic frequencies: ~3/min in the stomach, ~11–12/min in the duodenum, decreasing aborally. These slow waves set the maximum frequency at which smooth muscle can contract — if neural/hormonal triggers coincide with the peak of a slow wave, an action potential and contraction occur. ICC dysfunction (e.g., loss in diabetic gastroparesis, c-kit mutations in GIST) disrupts GI motility. They are not secretory or sensory cells.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.

Sponsored

Want to test yourself?

Create a free account for timed mock tests, mistake tracking, and FSRS spaced-repetition revision across 23,000+ MCQs.

Start free → Log in

More GIT Physiology (Secretions, Hormones, Motility, Absorption) MCQs

See all GIT Physiology (Secretions, Hormones, Motility, Absorption) MCQs →