Where are $Nissl$ granules absent?

Identify $P, Q,$ and $R$ in the given neuron.

Bundles of nerve fibres are enclosed in a sheath called

What are the two primary types of cells found in the nervous system?

Four healthy individuals suffer an injury at the age of $20$ years,which results in the damage and death of some cells. Which of the following cells will show the least amount of regeneration?

Nissl's granules are characteristically found in