Difference Between Axolemma and Neurilemma

When it comes to the anatomy of neurons, two terms that often get confused are “axolemma” and “neurilemma.” While they may sound similar, these structures play different roles in the function of nerve cells. In this article, we will explore the key differences between axolemma and neurilemma to help clarify their distinct functions.

Axolemma

The axolemma is the specialized membrane that surrounds the axon of a neuron. It is a phospholipid bilayer that serves as a barrier between the internal environment of the neuron and the external environment. The axolemma is responsible for maintaining the integrity of the axon and regulating the exchange of ions and other molecules between the inside and outside of the cell.

One of the key functions of the axolemma is to facilitate the propagation of action potentials along the length of the axon. Action potentials are electrical signals that travel down the axon and are essential for communication between neurons. The axolemma contains voltage-gated ion channels that open and close in response to changes in membrane potential, allowing ions to flow in and out of the cell to generate and propagate the action potential.

Neurilemma

On the other hand, the neurilemma, also known as the Schwann cell membrane, is a specialized membrane that surrounds the axon of a peripheral nerve cell. Unlike the axolemma, which is part of the neuron itself, the neurilemma is actually a separate cell that wraps around the axon in a spiral fashion. The primary function of the neurilemma is to provide structural support and insulation to the axon.
In addition to insulation, the neurilemma plays a crucial role in the regeneration of damaged nerve cells. When a peripheral nerve is injured, the Schwann cells that make up the neurilemma can proliferate and form a pathway for the regrowth of axons. This process, known as Wallerian degeneration and regeneration, is essential for restoring function to damaged nerves.

Key Differences

Now that we have a better understanding of the roles of axolemma and neurilemma, let’s summarize the key differences between these two structures:

1. Location: The axolemma is part of the neuron itself and surrounds the axon, while the neurilemma is a separate cell that wraps around the axon of peripheral nerve cells.
2. Function: The axolemma is responsible for maintaining the integrity of the axon, regulating ion exchange, and facilitating the propagation of action potentials. The neurilemma provides structural support, insulation, and plays a crucial role in nerve regeneration.
3. Composition: The axolemma is a phospholipid bilayer membrane, while the neurilemma is made up of Schwann cells.
   In conclusion, while both axolemma and neurilemma are important components of the nervous system, they serve distinct functions in the anatomy and physiology of neurons. Understanding the difference between these two structures is essential for grasping the complexity of nerve cell function and communication in the body.
   Next time you come across these terms, remember that the axolemma is the membrane surrounding the axon of a neuron, while the neurilemma is the Schwann cell membrane that wraps around the axon of peripheral nerve cells.