Which term describes a bundle of axons within the central nervous system?

Which term describes a bundle of axons within the central nervous system?

• A. Nerve
• B. Tract
• C. Ganglion
• D. Nucleus

Answer: (B)

Bundles of axons traveling together within the brain and spinal cord are called tracts. They form the white matter pathways that carry signals from one CNS region to another, such as motor commands descending from the cortex to the spinal cord via the corticospinal tract. In contrast, a nerve is a bundle of axons in the peripheral nervous system, a ganglion is a cluster of neuron cell bodies in the PNS, and a nucleus is a cluster of neuron cell bodies within the CNS. So the term for a CNS axon bundle is tract.

Bundles of axons traveling together within the brain and spinal cord are called tracts. They form the white matter pathways that carry signals from one CNS region to another, such as motor commands descending from the cortex to the spinal cord via the corticospinal tract. In contrast, a nerve is a bundle of axons in the peripheral nervous system, a ganglion is a cluster of neuron cell bodies in the PNS, and a nucleus is a cluster of neuron cell bodies within the CNS. So the term for a CNS axon bundle is tract.