55,874views
00:00 / 00:00
of complete
of complete
2024
2023
2022
2021
diverticulitis p. 390
Diverticula, or a single diverticulum, is this pouch that forms along the walls of a hollow structure in the body, kind of like a cave.
Usually we talk about these caves or pouches in the context of the large intestine, so it’d be a colonic diverticula, but it can also happen in the small intestine as well as other hollow structures in the body.
The walls of the large intestine are made up of several layers, starting with the inner layer, the mucosa, then the submucosa, then the muscle layer, and finally serosa.
Sometimes these little out-pouches include all the layers, from mucosa to serosa, and these are true diverticula, and sometimes only the mucosa and submucosa poke through the muscle layer, and these would be called pseudo or false diverticula, where the muscle layer isn’t included and the mucosa and submucosa are covered only by serosa.
Most of the time, diverticula in the large intestine are false diverticula.
It’s thought that the formation of colonic diverticula is a result of high pressures that literally push the walls such that they bubble out and form these pouches.
Now remember that the large intestine has this smooth muscle layer, right? And it’s able to contract using that muscle layer, just like any other muscle we contract, except that we can’t consciously control these because it’s smooth muscle rather than skeletal muscle.
This smooth muscle contraction accomplishes a couple things, like mixing ingested food and moving digested food toward the end of the line.
Whenever it contracts, though, higher pressures are generated inside the lumen, since it’s sort of like being squeezed and compressing the air inside, and normally you’d imagine that the higher pressure would be equally felt throughout the lumen, right?
Well, it’s thought that the contractions in patients with diverticula are exaggerated or abnormal in some way, which causes an unequal distribution of pressure with some specific areas having really high pressures during contractions.
It’s not quite clear exactly what leads to these abnormal contractions, but some studies suggest it may have to do with the smooth muscle itself.
Now let’s take a step back and think about something called Laplace’s law which says that the pressure on the wall of a cylinder is proportional to the inverse of its diameter, so as diameter decreases, pressure increases.
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.