Which cell is the basic unit of the nervous system and transmits nerve impulses?

• A. A neuron
• B. A glial cell
• C. A muscle cell
• D. A blood cell

Answer: (A)

Nerve signaling relies on a cell type that is specialized for carrying electrical information. The basic unit is the neuron. Neurons generate and transmit electrical impulses, called action potentials, along their axons to communicate with other neurons, muscles, or glands. They receive signals through dendrites, process them in the cell body, and send them onward via the axon. The speed of transmission is increased when the axon is insulated by myelin, with gaps called nodes of Ranvier facilitating rapid conduction. Communication at synapses uses neurotransmitters to pass the signal to the next cell.

Glial cells provide support, nourishment, and insulation for neurons but do not transmit impulses themselves in the same way neurons do. Muscle cells respond to neural input by contracting; they are effectors rather than the primary carriers of nerve impulses. Blood cells are components of the circulatory system and not involved in transmitting nerve impulses.