What is the basic functional unit of the nervous system visible under light microscopy?

What is the basic functional unit of the nervous system visible under light microscopy?

• A. Neuron with cell body and processes (dendrites and axon); glial support cells.
• B. Neuron with long axons only.
• C. Glial cells alone.
• D. Muscle cells with motor end plates.

Answer: (A)

The basic functional unit of the nervous system is the neuron. Under light microscopy, you can recognize a neuron by its cell body (soma) containing the nucleus and surrounding cytoplasm, from which processes extend. Dendrites branch off the cell body to receive input, while a single axon conducts signals away from the cell to other neurons or effectors. Glial cells accompany neurons and provide essential support, but they are not the primary signaling units. The other options misplace the focus: a long axon alone misses the neuron’s input-receiving dendrites and cell body; glial cells alone don’t perform neuronal signaling; muscle cells with motor end plates relate to the neuromuscular junction, not the neuronal unit seen in nerve tissue.

The basic functional unit of the nervous system is the neuron. Under light microscopy, you can recognize a neuron by its cell body (soma) containing the nucleus and surrounding cytoplasm, from which processes extend. Dendrites branch off the cell body to receive input, while a single axon conducts signals away from the cell to other neurons or effectors. Glial cells accompany neurons and provide essential support, but they are not the primary signaling units. The other options misplace the focus: a long axon alone misses the neuron’s input-receiving dendrites and cell body; glial cells alone don’t perform neuronal signaling; muscle cells with motor end plates relate to the neuromuscular junction, not the neuronal unit seen in nerve tissue.