Which layer is primarily responsible for motility in the digestive tract?

Which layer is primarily responsible for motility in the digestive tract?

• A. Mucosa
• B. Submucosa
• C. Muscularis
• D. Serosa

Answer: (C)

Motility in the digestive tract is produced by the smooth muscle in the muscularis externa, which has an inner circular layer and an outer longitudinal layer. The coordinated contractions of these two layers generate peristaltic waves that propel contents and segmentation that mix them. The enteric nervous system, especially the myenteric plexus located between these muscle layers, regulates the strength, frequency, and coordination of these contractions. The other layers have different roles: the mucosa lines the lumen and handles secretion and absorption; the submucosa supports the tissue and houses nerves that modulate secretion and blood flow; the serosa is the outer protective layer. So the muscularis is the key layer driving gut motility.

Motility in the digestive tract is produced by the smooth muscle in the muscularis externa, which has an inner circular layer and an outer longitudinal layer. The coordinated contractions of these two layers generate peristaltic waves that propel contents and segmentation that mix them. The enteric nervous system, especially the myenteric plexus located between these muscle layers, regulates the strength, frequency, and coordination of these contractions. The other layers have different roles: the mucosa lines the lumen and handles secretion and absorption; the submucosa supports the tissue and houses nerves that modulate secretion and blood flow; the serosa is the outer protective layer. So the muscularis is the key layer driving gut motility.