Coelom MCQ - Practice Questions with Answers

Coelom: 

• The coelom is the body cavity. 
• It is formed between endoderm and ectoderm, lined by the mesoderm on both sides.
• It is situated between the inner body wall and the visceral organs, such that it contains many visceral organs like kidneys, alimentary canal, lungs etc.
• It is filled with fluid.

 Based on the type of coelom, the animals can be of following types:

Acoelomate: 

• Those animals that do not develop a body cavity are called acoelomate. 
• The space between endoderm and ectoderm is filled with cellular mesoderm. 
• For example, Platyhelminthes.

Pseudocoelomate:

• A pseudocoelom or false coelom is formed by the scattered patches of the mesoderm. 
• It is not lined by the mesoderm completely.
• Animals having pseudocoelom are called pseudocoelomate. 
• For example, Aschelminthes.

Eucoelomate: 

• Those animals that have a well-defined body cavity lined with mesodermal cells on both sides. 
• It separates the inner body wall from the alimentary canal. 
• For example, annelids, molluscs, arthropods, echinoderms and chordates.
  

• The Eucoeloms are categorized into two types- schizocoelom and enterocoelom. They are categorized based on ways in which true body cavity or coelom arises in different animals.

1.  Schizocoelom : This body cavity is formed from splitting of mesoderm around the gut. Animals belonging to the Phyla Annelida, Mollusca, and Arthropoda show Schizocoelom cavity
2. Enterocoelom : It arises from outpocketing of the embryonic gut(endoderm). Animals belonging to the Phyla Echinodermata and Chordata show Enterocoelom