How does peristalsis help digestion

First we introduce food into the digestive system by way of the mouth. We chew and swallow it using enzymes from saliva to break down the food, which becomes known as abolus. The bolus passes through the esophagus and enters the stomach, where it encounters acids which further break down the bolus. The process continues into the intestinal tract. In the small intestine, the bolus continues to be reduced by digestion. When it finally reaches the large intestine, the bolus is more or less a waste product that is prompted through the bowel until its finally excreted.

One process that is common to nearly every part of the digestive system is the series of muscle contractions and relaxations that occur throughout the process to move the bolus from beginning to end and in a one-way direction. This movement has a wave-like quality, utilizing bands of smooth muscle to push the bolus through the system.

Peristaltic waves work regularly throughout much of the system, but tend to slow down considerably in the large intestine, which is designed to undergo only 2 or 3 periods of bowel evacuation daily, and almost never at night.

As noted in previous discussions about food and sleep here at the blog, circadian rhythms influence digestive system activity. Our body clocks use cues based on time, light, and activity including mealtime to prepare the body for sleep.

Research shows that sleep and circadian rhythms work in tandem to regulate appetite, metabolism, and absorption of nutrients. Eating also guides certain circadian oscillators which kick in during digestion to help manage the hunger drive and send messages to the brain when hunger has been satiated.

The speed of digestion at night naturally slows, and fewer relaxations and contractions of muscles occur during nonREM sleep though during REM, they can speed up. This is all part of an intelligently designed plan by our circadian rhythms to allow us to sleep for several hours at a time, unimpeded by the need to empty our bowels. It makes sense, then, that when circadian rhythms are disrupted, this leaves the digestive system open to problems with regulation and function.

These problems can present in any number of ways, such as:. When the feeding clock becomes disrupted on a regular basis for whatever reasoninternal mealtime rhythms may shift to adjust to this new schedule.

This is especially the case for people who work night shift or graveyard shift; their circadian systems eventually shift to a much later period for mealtime.

For others, a shift to later eating, followed soon after by bedtime, can lead to problems down the line with digestion. The digestive system needs time to process the meal, but cannot be as effective if sleep follows too soon after a meal due to these shifts. This complicates patterns of metabolism, lends to imbalances of important hormones related to both sleep and digestion leptin, ghrelin, melatonin, cortisol and can lead to obesity and metabolic disorders like Type II diabetes, as well as all the digestive problems listed above.

Sleep deprivation itself can increase the risk for overeating, glucose imbalances, and leptin resistance. Add late meals to the mix, and the problems to ones metabolism are compounded.

With each swallow a structure called the epiglottis closes over respiratory structures. The swallowed bolus stays on course and is directed toward the esophagus. One peristaltic wave can be enough to move a bolus down the esophagus and into the stomach. The walls of the alimentary canal include layers of smooth muscle controlled by the autonomic nervous system.

Alternating contraction and relaxation of these muscles is called peristalsis. Peristaltic waves push the swallowed bolus down the esophagus. In the stomach, peristalsis churns swallowed food, mixing it with gastric juices. These mechanical and chemical actions further break down food into a substance called chyme. It takes about a minute to chew a piece of food into a bolus and a few seconds to swallow it. Once in the stomach foodstuffs take a few hours to become chyme.

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Neurogastroenterol Motil. Intestinal pseudo-obstruction. Updated February Patel KS, Thavamani A. Physiology, peristalsis. Updated March 1, Katsanos KH, et al. Your Privacy Rights. To change or withdraw your consent choices for VerywellHealth.

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