Peristalsis

Keywords

Peristalsis, oesophagus, mouth, windpipe, stomach, bile, acid, gastric juice, intestinal, bolus, waves, muscles, absorb nutrients.

Introduction

When you eat food, it has to go through a jungle in your body. From sitting in your stomach, to being processed through the intestines, and then out the other end. Here we will look at how it moves from the stomach to the intestines through peristalsis.

What is Peristalsis?

The definition is this:

A series of wave-like contractions of the muscles that are involved in the food movement and in the movement of other liquid particles in the digestive tract to various processing organs that are located in the digestive system.

But what does this actually mean?

When we eat something (let's say a banana), and it sits in our mouth, we chew it. The saliva in our mouth starts to break down the food there, and once we have chewed it enough, it is swallowed. This is then referred to as oesophagal peristalsis.

Humans are only capable of single-movement peristalsis. Some animals like cattle, sheep and camels are able to perform reverse peristalsis, and this is where the food can be brought back to the mouth for further chewing.

The peristaltic wave continues from the oesophagus into the stomach, as it helps the food mix with the gastric juices - the highly acidic liquid that settles in your stomach to help with breakdown of foods - like your banana. There can be as many as three waves at once when this happens, and then they stop.

Interesting fact: food takes just 7 seconds to travel from the mouth down to the stomach because of peristalsis.

Intestinal Peristalsis

Now, you've eaten your food, it's travelled to the stomach, and the acids in there have broken the food down to acceptable sizes, it then moves to the small intestines. This is where intesinal peristalsis happens.

Your food at this point is no longer classes as food, and has been removed of some nutrients, but still has some way to go. There are still nutrients and proteins to be removed. This is done by lipase, which is an enzyme that helps break down further the remainder of the food, now called a bolus.

Vili are small hair-like structures that line the intestinal tract, and they absorb nutrients and minerals from the food you've eaten. They also help with the muscular movement of the food along the tract. They move back and forth, and work with the smooth muscles in the tract to move it along to the large intestine.