Neural signalling transmits information through neuron structure, ion gradients, action potentials, synapses and chemical modulation of postsynaptic responses, linking cellular mechanisms to rapid communication in nervous systems.
Coverage 2010–2025 · Updated 15 Jul 2026
• Neurons carry electrical impulses in the nervous system
• Motor, sensory, and relay neurons differ in axon, dendrite, and cell body arrangement
• Sodium-potassium pumps use ATP to move 3 Na⁺ out and 2 K⁺ in
• Ion gradients make the resting axon polarized at about -70 mV
• A nerve impulse is a propagated action potential along a nerve fibre
• Stimulus-triggered sodium influx reverses membrane polarity
• Larger axon diameter lowers resistance and increases impulse speed
• Myelin sheaths and nodes of Ranvier enable faster saltatory conduction
• Synapses connect neurons to neurons, muscles, or glands
• Chemical synapses transmit one way across a narrow synaptic cleft
• Action potentials open voltage-gated Ca²⁺ channels in presynaptic terminals
• Ca²⁺ causes vesicle fusion and neurotransmitter exocytosis into the cleft
• Neurotransmitters diffuse and bind receptors on the postsynaptic membrane
• EPSPs depolarize the membrane and make threshold more likely
