Question

Explain the nerve ring of earthworm

Answer 1

This arrangement means the brain, sub-pharyngeal ganglia and the circum-pharyngeal connectives form a nerve ring around the pharynx. The ventral nerve cord (formed by nerve cells and nerve fibres) begins at the sub-pharyngeal ganglia and extends below the alimentary canal to the most posterior body segment.

Answer 2

Here is your answer

The nervous system of earthworm consists of set of segmentally arranged nerve cells ganglia and a ventral nerve cord. Nerve ring is formed, when the nerve cord in the anterior region (3rd and 4th segments) bifurcates, laterally encircling the pharynx and joins the cerebral ganglia dorsally

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