The “gray matter of the brain is largely made up of which of the following?
A.
Neuron cell bodies
B.
Meninges
C.
Neuron cell axons
D.
Corpus callosum
The correct answer and Explanation is :
The correct answer is A. Neuron cell bodies.
Explanation:
The brain’s gray matter is primarily composed of neuron cell bodies, dendrites, unmyelinated axons, glial cells, and synapses. It contrasts with white matter, which primarily contains myelinated axons. Understanding the distinction between gray and white matter is crucial for grasping the brain’s functional organization.
1. Gray Matter Composition:
- Neuron Cell Bodies: These are the core processing units of the brain. Neurons receive, integrate, and transmit information. Gray matter contains a high density of these cell bodies, which are responsible for most of the brain’s complex processes, including sensory perception, memory, emotions, and muscle control.
- Dendrites and Synapses: Dendrites are extensions from neuron cell bodies that receive signals from other neurons. Synapses are the junctions where communication between neurons occurs.
- Glial Cells: These support neurons, provide nutrients, maintain homeostasis, and aid in immune defense.
2. White Matter Composition:
In contrast, white matter consists mainly of myelinated axons (option C), which are long projections of neurons that carry electrical signals from one part of the brain to another or to the spinal cord.
3. Other Incorrect Options:
- B. Meninges: These are protective layers that cover the brain and spinal cord. They do not constitute gray matter but rather serve to protect the central nervous system.
- D. Corpus Callosum: This is a large bundle of white matter fibers that connects the two hemispheres of the brain, facilitating communication between them. It does not contribute to gray matter.
In summary, gray matter, made up largely of neuron cell bodies, plays a crucial role in information processing and higher brain functions.