Which connective tissue layer surrounds individual axons within a peripheral nerve in cross-section?

• A. Epineurium
• B. Perineurium
• C. Myelin sheath
• D. Endoneurium

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the structure of a peripheral nerve. Peripheral nerves are composed of bundles of axons, which are organized into fascicles and surrounded by connective tissue layers.
2. Step 2: Learn the hierarchy of connective tissue layers in a peripheral nerve. The outermost layer is the epineurium, which surrounds the entire nerve. The perineurium encases individual fascicles (bundles of axons). The endoneurium is the innermost layer, surrounding individual axons.
3. Step 3: Differentiate between the connective tissue layers and the myelin sheath. The myelin sheath is not a connective tissue layer; it is a lipid-rich insulating layer produced by Schwann cells that wraps around certain axons to enhance signal transmission.
4. Step 4: Focus on the endoneurium. This delicate connective tissue layer surrounds each individual axon within a fascicle, providing structural support and maintaining the microenvironment for nerve function.
5. Step 5: Confirm the correct answer by matching the description of the endoneurium to the question. The endoneurium is the connective tissue layer that surrounds individual axons within a peripheral nerve in cross-section.