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The Alimentary Canal

The Alimentary Canal

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This lesson will describe the structure, including the four layers, of the digestive tract.

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Tutorial

What's Covered

Welcome to this lesson today on the layers of the alimentary canal. Today you'll be learning about the various layers of the alimentary canal. Specifically you will learn about:

  1. Alimentary Canal Overview
  2. Lumen and Mucosa
  3. Submucosa
  4. Smooth Muscle
  5. Serosa
  6. Sphincters

1. Alimentary Canal Overview

The alimentary canal is a fancy name for your digestive tract, and is actually composed of four layers and a lumen. Thoe four layers are the mucosa, submucosa, smooth muscle, and serosa.

Terms to Know

    • Digestive Tract
    • Technically is called the alimentary canal, 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 are the: mouth, esophagus, stomach, small intestine, colon (large intestine), rectum and anus.
    • Lumen
    • The name used to describe the hollow part of a hollow/tubular organ.
    • Mucosa
    • The mucous membranes of the alimentary canal, this is the layer of tissue of the alimentary canal that is in direct contact with its lumen.
    • Submucosa
    • The layer of tissue just below the mucosa, the submucosa contains glands that secrete onto the mucosa and well as capillaries and lymph vessels.
    • Smooth Muscle
    • The tissue layer of the alimentary canal that controls its muscular movements, also called the muscularis.
    • Serosa
    • The outermost layer of tissue of the alimentary canal that produces and secretes a watery secretion to reduce friction while digestive organs are moving.

2. Lumen and Mucosa

The lumen is the hollow part of the digestive tract that the food we consume travels through. The actual first a layer of our digestive tract is the mucosa and remember, the mucosa is the innermost layer of the digestive tract. The lumen has contact with the lumen and is made up of epithelial cells.


3. Submucosa

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 the way in which nutrients from food can move into the bloodstream and is also how the mucosa receives blood.


4. Smooth Muscle

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.


5. Serosa

Our last layer is the serosa which is a very thin layer. It's a thin outer covering of the digestive tract and it's kind of moist and slippery. The function of the serosa is to reduce friction, because digestive tract bunched up inside your abdomen and is coming in contact with some of your other organs.


6. Sphincter

Sphincters are basically smooth muscles that are found between the various sections of the digestive tract.

Term to Know

    • Sphincters
    • Sphincters are muscles that control the openings between organs; controlling what enters and exits various organs.

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 movement of food through the digestive tract.


Summary

This lesson has been an overview on the layers of alimentary canal. Specifically, you learned about the layers of the lumen, mucosa, submucosa, smooth musical, and the serosa. You also learned a little about the sphincter.

Keep up the learning and have a great day!

Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

TERMS TO KNOW
  • Digestive Tract

    Technically is called the alimentary canal, 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 are the: mouth, esophagus, stomach, small intestine, colon (large intestine), rectum and anus.

  • Sphincters

    Sphincters are muscles that control the openings between organs; sphincters control what enters and exits various organs.

  • Mucosa

    The mucous membranes of the alimentary canal, this is the layer of tissue of the alimentary canal that is in direct contact with its lumen.

  • Lumen

    The name used to describe the hollow part of a hollow/tubular organ.

  • Submucosa

    The layer of tissue just below the mucosa, the submucosa contains glands that secrete onto the mucosa and well as capillaries and lymph vessels.

  • Smooth Muscle

    The tissue layer of the alimentary canal that controls its muscular movements, also called the muscularis.

  • Serosa

    The outermost layer of tissue of the alimentary canal that produces and secretes a watery secretion to reduce friction while digestive organs are moving.