Physiology 3120 Study Guide - Resting Potential, Electrochemical Gradient, Membrane Potential
Document Summary
So, in the last module you learned about ion concentration and membrane potentials. Almost all cells have membrane potentials that are generated by the electrochemical gradient of the major ions. Membrane potentials are essential for generating action potentials, the language of the brain, communicated via neurons. Every sense we detect, every movement we make, requires the generation of action potentials. You should know the different phases of the action potential: depolarization- the resting membrane potential goes from -70 mv to + 35 mv (this is very quick, 1/1000 of a second: repolarization- the return of the membrane potential back to -70 mv, hyperpolarization- the membrane potential becomes more negative (-90 mv) for a period of time and the slowly returns to -70 mv. These channels respond (open) due to changes in voltage; that is why they are called voltage-gated channels. There are two types of voltage-gated channels involved in action potentials, na+ and k+ voltage-gated channels: voltage gated sodium channels.