Chapter 6: Neuronal Signaling and Synaptic Transmission

Neuronal Signaling and Synaptic Transmission examines how action potentials are generated and propagated via voltage-gated sodium and potassium channels, with emphasis on the all-or-none principle, refractory periods, and saltatory conduction in myelinated axons. The chapter then transitions to synaptic transmission, distinguishing between electrical and chemical synapses, and detailing the steps involved in neurotransmitter release, including calcium influx, vesicle fusion, and exocytosis. Various neurotransmitters—such as acetylcholine, GABA, dopamine, and serotonin—are discussed, alongside receptor types including ionotropic and metabotropic receptors. Synaptic integration is explained through excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs), spatial and temporal summation, and neuronal coding of stimulus strength. The chapter also covers mechanisms of neural plasticity, such as long-term potentiation and habituation, and introduces glial cells, including astrocytes and Schwann cells, as essential for supporting neuronal function. Finally, it links cellular signaling to behavioral responses, emphasizing the nervous system’s role in rapid, precise coordination of physiological processes.