Nervous sheath

Pronunciation
/NERV-us sheath/
Category
Anatomy
Plural
Nervous sheaths

Definition

A protective outer covering surrounding insect ganglia, connectives, and nerve trunks. It consists of an inner cellular layer called the perineurium (perilemma) and an outer noncellular layer called the neurilemma.

Etymology

From Latin 'nervus' meaning 'nerve' and 'sheath' referring to a protective covering.

Example

The nervous sheath acts as a blood barrier, preventing free exchange of ions with the blood.

Related Terms

  • Ganglia
  • Connectives
  • Neurilemma
  • Perilemma