Anatomy Practice Exam

What is meant by 'white matter' in the central nervous system?

1. Regions abundant in cell bodies of neurons

2. Areas with more myelin sheaths than neuronal cell bodies

3. Parts lacking axons and myelin sheaths

4. Portions involved in reflex responses

The correct answer is: Areas with more myelin sheaths than neuronal cell bodies

'White matter' in the central nervous system refers specifically to areas where there is a high concentration of myelinated axons. Myelin is a fatty substance that surrounds the axons of neurons and appears white in color, which is why these regions are termed 'white matter.' The presence of myelin sheaths enhances the speed and efficiency of electrical signal transmission between nerve cells. This distinctive feature differentiates it from 'grey matter,' which contains a higher density of neuron cell bodies, dendrites, and unmyelinated axons. In white matter, the conduction pathways are primarily made up of myelinated axons that connect different brain regions and facilitate communication within the nervous system. The focus on myelination is essential for understanding how information flows through the brain and spinal cord, underscoring the importance of white matter in facilitating rapid communication between different parts of the central nervous system.