Increase in Peristalsis

Increase in Peristalsis

We know that a lot of movement in the pipe of the body occurs through peristalsis. The action of the heart muscle is one such example, although, of course, the blood does not go backwards into the chambers because of the valves’ action. These valves are flaps of fibrous tissue that come together and stop return flow. Valves are present in the veins, as well, directing the blood in the appropriate direction. The lymphatic system has valves, and the term valves is also used in reference to the pipe we call our gastrointestinal tract, or gut. Muscles contract in a rhythmic manner, causing a wave of contraction down the pipe. This is seen be on inspecting the movements of the esophagus and the small intestine. Yet because these organs do not have one-way valves, like those in the heart, fluid can travel back-and-forth in spite of these peristaltic waves. Indeed, the digestive processes in the gut are dependent on slushing the fluid, the digestive juices, mixing them and churning them, and therefore this peristaltic phenomenon is not exclusively unidirectional. Peristalsis as such, however, is not a prime feature of the large bowel. Here we speak of contractions of the whole organ, or at least sections of it, particularly contractions of the longitudinal fibers, and large quantities of contents are propelled forward, and occasionally backward, through what is called mass action.

Most people are familiar with the phenomenon that the urge to move their bowels occurs sometimes after a meal, typically breakfast, and very often after ingesting a stimulant such as coffee. This is an example of a generalized contraction of the organ (the colon) that propels the contents into the vestibule where it is held temporarily before evacuation. The contents of the small intestine pass through the sphincter which separates it from the first part of the colon, called the cecum (on the left side of the abdomen), and the circular muscle at the lower end of the terminal ilium, the small bowel, is indeed mostly contracted or closed. The liquid contents of the small intestine are squirted in small quantities, following peristaltic activity, into the cecum. The cecum itself serves predominantly as a reservoir, the site where the dehydrating process begins and the site where bacterial fermentation begins and occurs predominantly. The cecum is, to a certain extent, a dead end, and its appendage, the appendix, is a complete dead end. It is in the appendix, of course, that chronic inflammation and infection occurs most frequently - hence the disease of appendicitis.

It is interesting that there are accounts of instances in which casts of a colon’s lining are reputed to be excreted en masse. Almost certainly, these instances represent mostly a combination of shed lining from the cecum with contents that had become inspissated and adherent to the lining of the cecum - the continuous flow of contents from the small intestine into the bowel beyond the cecum, passing through these concretions. There are multiple, though infrequent, accounts of people passing contents from their bowels that are recognized to have been ingested a long time earlier. These concretions likely have been held in the periphery of the cecum, while the otherwise continuous flow of contents passes through the center of the cecum into the ascending colon. It is also not unlikely that some of this phenomenon of sluggishness, of stasis, at the bowel surface can occur in the ascending and transverse colons, as well, with the contents merely going through the center and being propelled through the phenomenon of mass action. Is it an advantage for a person to have longstanding concretions in this organ? Of course not. I must report, however, that in the process of inspecting the lining of this organ with a colonoscope, a procedure that I have had occasion to perform many times, one does not ordinarily see large residues in this site. How might this be? How can it be that there are reliable accounts of these casts that are not seen by the endoscopist? I have come to the conclusion that the answer is that, in preparation for endoscopy, the patient invariably is asked to take a strong purgative to clean out the contents of the bowel so the endoscopist can indeed inspect the lining. These purgations must remove any material that might have been static in this situation and therefore are not observed when the endoscopic inspection is performed.