Electrical communication is due to which?

• A. Ions (charged molecules) inside the neuron
• B. Neurotransmitters in the synapse
• C. Blood flow
• D. Glial cells

Answer: (A)

Electrical communication in the nervous system comes from ions moving across the neuron's membrane, creating and propagating electrical signals. The resting membrane potential exists because there are different ion concentrations inside and outside the neuron and because the membrane is selectively permeable. When stimulated, voltage-gated sodium channels open and Na+ rushes in, causing depolarization and triggering an action potential that travels along the axon. Potassium channels then open to let K+ exit and restore the resting state. This whole process is electrical, since it involves flows of charged particles and rapid changes in membrane potential. Neurotransmitters, by contrast, operate at chemical synapses to convey signals between neurons, not within a neuron’s membrane potential. Blood flow and glial cells don’t generate the electrical signal themselves (though myelination by glial cells affects how fast it travels).