Which connective tissue forms the outermost protective covering of a peripheral nerve?

Which connective tissue forms the outermost protective covering of a peripheral nerve?

• A. Epineurium
• B. Perineurium
• C. Peripheral nerve
• D. Nodes of Ranvier

Answer: (A)

In peripheral nerves, connective tissue layers wrap the nerve in concentric coverings, with the outermost being the epineurium. This tough sheath is made of dense irregular connective tissue and encloses the entire nerve and its fascicles, containing blood vessels and sometimes fat. It provides mechanical protection and helps anchor the nerve to surrounding tissues. Just inside this layer, the perineurium surrounds each fascicle, forming a diffusion barrier that helps protect the enclosed nerve fibers. Within each fascicle, the endoneurium surrounds individual nerve fibers. Nodes of Ranvier are gaps in the myelin sheath along a myelinated axon, not a wrapping around the nerve. So the outermost protective covering is the epineurium.

In peripheral nerves, connective tissue layers wrap the nerve in concentric coverings, with the outermost being the epineurium. This tough sheath is made of dense irregular connective tissue and encloses the entire nerve and its fascicles, containing blood vessels and sometimes fat. It provides mechanical protection and helps anchor the nerve to surrounding tissues.

Just inside this layer, the perineurium surrounds each fascicle, forming a diffusion barrier that helps protect the enclosed nerve fibers. Within each fascicle, the endoneurium surrounds individual nerve fibers.

Nodes of Ranvier are gaps in the myelin sheath along a myelinated axon, not a wrapping around the nerve. So the outermost protective covering is the epineurium.