Excretory system of Earthworm MCQ - Practice Questions with Answers

 Excretory system of Earthworm

• The excretory system of earthworm consists of segmentally arranged coiled tubes called nephridia
• The major function of nephridia is to regulate the volume and composition of the body fluids
• A nephridium starts as a funnel which collects excess fluid from coelomic chamber
• The tubular part of the nephridium delivers the wastes through a pore to the surface in the body wall into the digestive tube
• The nephridia are of three types i.e. pharyngeal nephridia, integumentary nephridia and septal nephridia

Integumentary nephridia 

• These are V-shaped nephridia attached to the lining of the body wall of segment 3 to the last which open to outside through nephridiopores 
• These nephridiopores are minute openings present on the body surface. 

Septal nephridia

• These are the largest nephridia in earthworm
• These are arranged along the sides of the intersegmental septum from 15th segment onwards
• These open into the intestines

​​​​​​​Pharyngeal nephridia 

• It is present as three paired tufts in the 4th, 5th and 6th segments on either side of the pharynx and oesophagus
• They open into buccal cavity and pharynx
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