Question

The supporting cells that form myelin sheaths in the peripheral nervous system are a. oligodendrocytes. b. satellite cells. c. Schwann cells. d. astrocytes. e. microglia.

Short answer

The supporting cells that form myelin sheaths in the peripheral nervous system are Schwann cells.

Step-by-step solution

Understand the question

The question is asking for the type of supporting cell that forms myelin sheaths in the peripheral nervous system. Myelin sheaths are layers of insulation around nerve fibers that help speed up the transmission of electrical signals.

Know the different types of glial cells

Glial cells provide support and protection to neurons. There are several types of glial cells, including oligodendrocytes, Schwann cells, satellite cells, astrocytes, and microglia.

Identify the role of each glial cell type

Here is a brief overview of each type of glial cell: a. Oligodendrocytes - These cells form myelin sheaths around the axons of neurons in the central nervous system (CNS). b. Satellite cells - These cells surround and provide support to the cell bodies of neurons in the peripheral nervous system (PNS). c. Schwann cells - These cells form myelin sheaths around the axons of neurons in the peripheral nervous system (PNS). d. Astrocytes - These cells provide support and nutrients to neurons in the central nervous system (CNS). e. Microglia - These cells act as the immune system of the central nervous system (CNS), by removing debris and unwanted substances.

Determine the correct answer

Based on the roles of each glial cell type, it is clear that Schwann cells (c) are responsible for forming myelin sheaths in the peripheral nervous system. Therefore, the correct answer is: c. Schwann cells

Key concepts

Schwann Cells

Schwann cells are a type of glial cell vital for the functioning of the peripheral nervous system (PNS). They wrap around the axons of neurons, creating a protective and insulating cover known as the myelin sheath. This sheath greatly enhances the speed at which electrical signals travel through neurons, essentially boosting nerve impulse conduction efficiency.

Schwann cells perform several critical roles, including:

• Insulating nerve fibers to improve signal transmission.
• Supporting nerve regeneration and repair post-injury.
• Helping maintain and balance the environment around nerve cells.

These cells contribute significantly to nerve health and functionality. Schwann cells are often compared with oligodendrocytes, which form myelin in the central nervous system, showing how specialized and localized the body's supportive cellular systems can be.

Myelin Sheaths

Myelin sheaths are vital structures produced by Schwann cells in the peripheral nervous system, meant to cover and protect nerve fibers. Imagine them as the insulation around electrical wires, enhancing the speed and efficiency of electrical signal transmission along the neurons.

The formation process of myelin sheaths involves Schwann cells wrapping around axons multiple times, creating a thick, layered coverage known as myelination. This process is essential because:

• It accelerates nerve impulse conduction by allowing signals to "jump" between nodes, points without myelin along the axon, through a mechanism called saltatory conduction.
• It provides protection and nutritional support to the neuron.

A lack of proper myelination can result in severe neurological issues, demonstrating just how pivotal these sheaths are to normal nervous system operation.

Peripheral Nervous System

The peripheral nervous system (PNS) serves as the communication relay between the central nervous system (CNS) and the rest of the body. It encompasses all the nerves lying outside the brain and spinal cord.

The PNS is divided into:

• Somatic nervous system, which controls voluntary movements via skeletal muscles.
• Autonomic nervous system, regulating involuntary body functions like heartbeat and digestion.

Schwann cells play an integral role in the PNS since they form the myelin sheaths that allow rapid transmission of electrical signals. This system ensures that our bodies respond swiftly to environmental cues and maintain internal stability. The PNS's responsiveness largely hinges on the condition of its glial support, particularly the health of Schwann cells and their myelin sheaths.