Which connective tissue surrounds each fascicle within a nerve?

Which connective tissue surrounds each fascicle within a nerve?

• A. Perineurium
• B. Epineurium
• C. Nodes of Ranvier
• D. Clefts of Schmidt-Lanterman

Answer: (A)

Think about how a peripheral nerve is organized in layers. Each bundle of nerve fibers, called a fascicle, is wrapped by a sheath known as the perineurium. This connective tissue layer groups fibers into fascicles and provides a protective barrier with tight junctions, helping maintain the nerve’s internal environment and contributing to the blood-nerve barrier. The endoneurium surrounds individual axons within the fascicle, while the epineurium surrounds the entire nerve. Nodes of Ranvier are gaps in the myelin sheath along the axon, not a surrounding tissue. Clefts of Schmidt-Lanterman are small channels within the myelin produced by Schwann cells, not protective sheaths around fascicles.

Think about how a peripheral nerve is organized in layers. Each bundle of nerve fibers, called a fascicle, is wrapped by a sheath known as the perineurium. This connective tissue layer groups fibers into fascicles and provides a protective barrier with tight junctions, helping maintain the nerve’s internal environment and contributing to the blood-nerve barrier. The endoneurium surrounds individual axons within the fascicle, while the epineurium surrounds the entire nerve.

Nodes of Ranvier are gaps in the myelin sheath along the axon, not a surrounding tissue. Clefts of Schmidt-Lanterman are small channels within the myelin produced by Schwann cells, not protective sheaths around fascicles.