BIOL 3070 Lecture Notes - Lecture 7: Sodium-Potassium Alloy, Antiporter, Cardiac Muscle
Document Summary
Graph va potential (myocardial ap: when ventricular cell receives depol. Fast sodium channels: because of large electrochemical gradient between outside of the membrane and inside of the cell, na+ ions rush into cell causing depol. Due to influx of sodium unlike influx of calcium led to large depol. in. L-type calcium channels (sometimes called slow l-type calcium channels: because of large concentration diff. between extra/intracell. Ca2+ channels rush in and cause plateau phase: calcium ions then bind to troponin that binds to tropomyosin complex and allows contraction of muscle, this is the main movement of ions involved in va ap. Rising phase (rapid influx of sodium due to opening of v-gated sodium channels) Falling (repolarization) phase (opening of v-gated potassium channels) Excitation-contraction: lots calcium coming in during plateau phase of ventricular ap (this initiates excitation-contraction coupling, ap enters from adjacent cell and causes opening of l-type v-gated ca channels on membrane (majority of these channels located around t-tubules.
