• Welcome to Crohn's Forum, a support group for people with all forms of IBD. While this community is not a substitute for doctor's advice and we cannot treat or diagnose, we find being able to communicate with others who have IBD is invaluable as we navigate our struggles and celebrate our successes. We invite you to join us.

Overview of the small intestine and colon.

Encyclopedia Britannica has one of the better overviews of the small intestine.

I think it's important to mention that the small intestine is a very muscular organ, because we have recently seen in studies that wall thickening and strictures are not primarily caused by fibrotic tissue but mostly by chronic inflammation resulting in an increase in smooth muscle tissue, it is a form of hyperplasia of muscle tissue.

Anyway, this is a great image. Note all the muscle layers of the small intestine.


colon image
Last edited:
The increase in smooth muscle tissue in crohn's (which is behind the wall thickening and stricturing) is very similar to that seen in asthma, where inflammation results in smooth muscle changes, which can result in narrowing of the airway in patients, it is a very similar mechanic in crohn's disease, where a remodeling of smooth muscle tissue results in similar changes, an increase in collagen deposition and increase in wall thickness.

Last edited: