BIO 12 Lecture Notes - Lecture 25: Extracellular Fluid, Resting Potential, Axon Terminal

• School: Irvine Valley College
• Department: Biology
• Course: BIO 12
• Professor: dorner

Document Summary

Compare and contrast continuous and salutatory action potential propagation (conduction: a distinguishing characteristic of action potentials is that they can travel over long distances of a meter or more without losing energy; a process known as conduction. Na+ then enters the axon and the initial segment of axon depolarizes. Positive charge from the depolarized trigger zone spreads by local current flow to adjacent sections of membrane and is repelled by the na+ that entered the cytoplasm and attracted by the negative charge of the resting membrane potential. The flow of local current toward the axon terminal begins conduction of the action potential. When the membrane distal to the trigger zone depolarizes from local current, its na+ channels open, allowing na+ into the cell. This starts the positive feedback loop: depolarization opens na+ channels more depolarization more. The conduction is similar as continuous propagation except that it only occurs at the nodes of ranvier.