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The alimentary canal is a scientific name for your digestive tract. The digestive tract consists of the organs that perform the main functions of the digestive system: ingestion, digestion, absorption, and excretion. The organs of the digestive tract include the mouth, esophagus, stomach, small intestine, colon (large intestine), rectum and anus.
The alimentary canal is composed of four layers and a lumen. The four layers are:
The lumen is the hollow part of the digestive tract that the food we consume travels through. The actual first layer of our digestive tract is the mucosa. The mucosa is the innermost layer of the digestive tract. The mucosa has contact with the lumen.
Our second layer of the digestive tract is the submucosa, which is a form of connective tissue. This connective tissue contains blood vessels and nerve cells. This is how nutrients from food can move into the bloodstream and also how the mucosa receives blood.
Smooth muscle makes up the third layer of the alimentary canal and is actually composed of two sublayers that run perpendicular to each other. The purpose of these smooth muscles in the digestive tract is that they aid in peristalsis. Peristalsis is the muscle contractions that help push food through the digestive tract.
Our last layer is the serosa, which is a very thin layer. It's a thin outer covering of the digestive tract and is moist and slippery. The function of the serosa is to reduce friction because the digestive tract is bunched up inside your abdomen. Digesting food is constantly moving via peristalsis and is coming in contact with some of your other organs.
Sphincters are basically smooth muscles that are found between the various sections of the digestive tract.
Sphincters help manage or control the movement of food through the digestive tract. An example is the sphincter between our esophagus and our stomach. This sphincter will allow food from the esophagus into the stomach but doesn't allow food to move in reverse. We also have another one that connects the stomach to the small intestine. Again, sphincters are helping to control the movement of food through the digestive tract.
Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND