Question 27

Neuron cell bodies primarily make up the 'gray matter' of the brain.

Gray matter consists mainly of neuronal cell bodies, which are responsible for processing and integrating information in the brain.

A) Meninges

Meninges are protective membranes that cover the brain and spinal cord, but they do not contribute to the structural or functional composition of gray matter. Therefore, this option is incorrect.

B) Neuron cell bodies

Neuron cell bodies are the primary constituents of gray matter, housing the nucleus and organelles necessary for neuronal function. This makes option B the correct answer, as it directly relates to the definition of gray matter.

C) Corpus callosum

The corpus callosum is a structure made up of white matter that connects the left and right hemispheres of the brain. It primarily contains myelinated axons, thus it does not make up gray matter, making this option incorrect.

D) Neuron cell axons

Neuron cell axons are part of white matter, as they are responsible for transmitting signals away from the neuron. Since gray matter is defined by the presence of cell bodies, this option is incorrect.

Conclusion

The correct answer is B, as neuron cell bodies are the defining feature of gray matter, critical for processing information in the brain. All other options, including meninges, corpus callosum, and neuron cell axons, are associated with different structures or functions that do not pertain to gray matter.