Endoneurium is a delicate layer of connective tissue that surrounds individual nerve fibers within a nerve. It provides support and protection to the axons, which are the long projections of nerve cells that transmit signals. The endoneurium contains collagen fibers, fibroblasts, and a small amount of extracellular matrix, contributing to the overall structure and function of the nerve. This protective layer plays a crucial role in maintaining the health of nerve fibers. It helps to insulate the axons, facilitating efficient signal transmission. Additionally, the endoneurium aids in the repair process following nerve injury, promoting regeneration and recovery of nerve function.