The key difference between gastrovascular cavity and alimentary canal is that gastrovascular cavity is a two-way digestive tract which has only one opening while the alimentary canal is a one-way digestive tract which has two openings.
Based on the body plan, organisms can be primitive or advanced. Gastrovascular cavity and alimentary canal are two body organs. The gastrovascular cavity is the body cavity that has elaborated into a highly branched canal system with both digestive and circulatory functions. Animals belonging to primitive phyla Cnidaria and Platyhelminthes have this kind of body cavity with a single opening. The alimentary canal is an organ by which food enters our body and moves out through the anus after digestion. It extends from mouth to anus. All vertebrates and most invertebrates have an alimentary canal.
CONTENTS
1. Overview and Key Difference
2. What is Gastrovascular Cavity
3. What is Alimentary Canal
4. Side by Side Comparison – Gastrovascular Cavity vs Alimentary Canal in Tabular Form
5. Summary
What is Gastrovascular Cavity?
The gastrovascular cavity is a digestive tract found in two major primitive phyla in kingdom Animalia. It is a primary organ involved in the digestion of food and circulation of nutrients throughout the body. Moreover, the gastrovascular cavity aids in the circulation of oxygen and wastes. The gastrovascular cavity has only one opening to the environment. This opening serves as both mouth and anus. Food goes in, and waste goes out from the same opening, making it a two-way digestive tract. The gastrovascular cavity is an extensively branched canal system. Only two phyla of kingdom Animalia have a gastrovascular cavity. Those phyla are phylum Cnidaria and phylum Platyhelminthes. The gastrovascular cavity in cnidarians is known as coelenteron.
Figure 01: Gastrovascular Cavity of the Flatworm Dugesia
What is Alimentary Canal?
The alimentary canal is an organ which extends from mouth to anus. It is the muscular tube by which food enters our body and moves out through the anus after digestion. Therefore, there are two openings in the alimentary canal, making it a one-way digestive tract. Foods go in through the mouth, and wastes are excreted out from the anus. The primary function of the alimentary canal is food digestion.
Figure 02: Alimentary Canal
The alimentary canal has several parts/organs. They are mouth and oral cavity, oesophagus, stomach, small intestine and large intestine. The human alimentary canal consists of a mouth, pharynx, oesophagus, stomach, small intestine, large intestine, and anus. All vertebrates and most invertebrates have an alimentary canal.
What is the Difference Between Gastrovascular Cavity and Alimentary Canal?
The gastrovascular cavity is a primitive organ/body cavity which helps in both food digestion and nutrient distribution throughout the body. On the other hand, the alimentary canal is a muscular tube primarily involved in food digestion. Moreover, the gastrovascular cavity has only one opening which serves both the mouth and anus while the alimentary canal has two openings: a mouth and an anus. So, this is the key difference between gastrovascular cavity and alimentary canal. Primitive organisms in phyla Cnidaria and Platyhelminthes have a gastrovascular cavity while all vertebrates and most invertebrates have an alimentary canal.
Below infographic shows the differences between gastrovascular cavity and alimentary canal in tabular form.
Summary – Gastrovascular Cavity vs Alimentary Canal
The gastrovascular cavity is a body cavity that functions in food digestion, as well as circulation of nutrients throughout the body. It has only one opening which serves both as a mouth and anus. Organisms having a gastrovascular cavity are very simple and made from few tissues. In contrast to that, the alimentary canal is a digestive tract which has two openings: mouth and anus. It primarily is involved in food digestion. All vertebrates and most invertebrates have an alimentary canal. However, it widely varies in organisms. This summarizes the difference between gastrovascular cavity and alimentary canal.
Reference:
1. “Gastrovascular Cavity: Definition & Explanation.” Study.com, Available here.
2. “Gastrointestinal Tract.” Wikipedia, Wikimedia Foundation, 19 Oct. 2020, Available here.
Image Courtesy:
1. “Dugesia Anatomy schematic” By Andreas Neudecker This W3C-unspecified vector image was created with Inkscape. – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Stomach colon rectum diagram-en” By William Crochot – US PD picture (Public Domain) via Commons Wikimedia