What is the loose connective tissue that encloses axons and their myelin sheaths?

What is the loose connective tissue that encloses axons and their myelin sheaths?

• A. epineurium
• B. perineurium
• C. endoneurium
• D. myelin sheath

Answer: (C)

The endoneurium is the delicate loose connective tissue that wraps each individual nerve fiber, along with its myelin sheath, inside a nerve fascicle. It provides a supportive environment for the axon and its Schwann-cell–formed myelin, and contains capillaries that nourish the fiber. Surrounding groups of fibers is the perineurium, which forms fascicles, and the outermost layer is the epineurium, which encases the entire nerve. The myelin sheath itself is produced by Schwann cells around the axon and is not the connective tissue layer wrapping the fiber. So, the tissue that encloses axons and their myelin sheaths is the endoneurium.

The endoneurium is the delicate loose connective tissue that wraps each individual nerve fiber, along with its myelin sheath, inside a nerve fascicle. It provides a supportive environment for the axon and its Schwann-cell–formed myelin, and contains capillaries that nourish the fiber. Surrounding groups of fibers is the perineurium, which forms fascicles, and the outermost layer is the epineurium, which encases the entire nerve. The myelin sheath itself is produced by Schwann cells around the axon and is not the connective tissue layer wrapping the fiber. So, the tissue that encloses axons and their myelin sheaths is the endoneurium.