Physio 04: Excitable Tissue: Nerve

The nervous system is the body’s communication infrastructure. Before muscles contract, before glands secrete, before awareness emerges, electrical signals race along neurons with speed, precision, and purpose.In this episode, Medlock Holmes examines excitable nerve tissue—the physiological basis of rapid signalling. We explore how neurons generate resting membrane potentials, how action potentials are triggered and propagated, and how ionic gradients store energy as information. Rather than treating electricity as a metaphor, we treat it as what it truly is in physiology: controlled charge movement governed by membrane architecture.This episode builds the logic of neuronal signalling from first principles—ion channels, threshold, refractory periods, and conduction velocity—so that later discussions of reflexes, sensation, and cognition rest on solid ground.Here, physiology learns to speak in voltage.Key Takeaways* Neurons convert ionic gradients into rapid electrical signals* Resting membrane potential is an active, maintained state* Action potentials are all-or-none events governed by threshold* Conduction speed depends on diameter and myelination* Excitability allows precise timing across long distances This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe