Final answer:
In the nervous system, the nucleus and ganglion are collections of neuron cell bodies in the CNS and PNS, respectively. Tracts are bundles of axons in the CNS, while nerves are axon bundles in the PNS. The somatic neuron controls muscles, the motor neuron signals muscles, and the sensory neuron detects stimuli; afferent carries signals toward the CNS and efferent carries them away.
Step-by-step explanation:
Defining various terms related to the nervous system is essential to understanding its structure and function:
- Nucleus: In the context of neuroanatomy, it refers to a localized collection of neuron cell bodies within the central nervous system (CNS).
- Ganglion: A cluster of neuron cell bodies in the peripheral nervous system (PNS).
- Tract: A bundle of axons within the CNS.
- Somatic neuron: A neuron that is part of the somatic nervous system, mainly involved in controlling voluntary muscle movements.
- Motor neuron: Type of neuron that transmits signals from the CNS to the muscles, facilitating movement; these are efferent nerves (efferent means "moving away from the CNS").
- Sensory neuron: A neuron that detects stimuli and transmits the sensory information to the CNS; these are afferent nerves (afferent means "moving toward the CNS").
- Afferent: Fibers or nerves carrying sensory information toward the CNS.
- Efferent: Fibers or nerves carrying signals away from the CNS to the effector organs such as muscles.
- Nerve: A bundle of axons in the PNS that transmits electrical signals; may contain both motor (efferent) and sensory (afferent) axons.
With this in mind, the correct definitions in the context of the nervous system are:
- Nucleus: Genetic material center
- Ganglion: Sensory neuron cluster
- Tract: Efferent nerve bundle
- Somatic neuron: Muscle control
- Motor neuron: Muscle control
- Sensory neuron: Stimulus detection
- Afferent: Toward CNS
- Efferent: Away from CNS
- Nerve: Axon bundle
The correct option that matches these definitions is Option B.