Potencial de Acción para Biofísica CBC - GHIRARDOSI

1) The Sodium (Na+) and Potassium (K+) Pump: This pump facilitates the efflux of 3 Na+ ions and the influx of 2 K+ ions during hyperpolarization. Potassium kinetics are slower and sodium kinetics are faster at this stage. 2) Depolarization - Passive transport - Opening of Na+ channels - Influx (massive influx) 3) Repolarization - Passive transport - Opening of K+ channels - Efflux (massive outflow) 4) All-or-None Law: The cell responds with an action potential that is exactly the same (in time and potential difference) to any threshold or suprathreshold stimulus. 5) Absolute Refractory Period (ARP): This period extends from the point when the cell reaches its maximum positive membrane potential until the second third of repolarization. During this period, a second stimulus cannot generate another action potential because the voltage-gated sodium channels are inactive. 6) Relative refractory period (RRP): From the third third of repolarization until hyperpolarization. It is characterized by requiring a suprathreshold stimulus to generate an action potential. 7) Nodes of Ranvier: These allow the propagation of the action potential, occurring between nodes and known as saltatory propagation. 8) Stimulus: Anything that can generate a response. Based on its origin, it can be classified as: Physical (mechanical, electrical, thermal) and chemical. Based on its intensity: Subthreshold, Threshold, and Suprathreshold.