BIOL 1100 Lecture Notes - Lecture 2: Cyclic Adenosine Monophosphate, Cyclic Nucleotide, Ion

• School: Brown University
• Department: Biology
• Course: BIOL 1100
• Professor: Zimmerman Anita

Document Summary

Injection of k+ changes the voltage the most because there is already so much inside, many channels open. Even at the injection site, the voltage doesn"t stay up, it fades away because some ions have flowed out of the cell. Over time (v1-->v3), losing net voltage: this is what happens when you don"t set it up for action potentials. Need to set it up to be able to recharge. K+ ions find v-gated na+ channels --> more na+ comes in --> + charge activates next v- gated na+ channel, etc: at the initiation site, might look a little different. If there is a synapse at initiation site, there is a depolarization hump before the voltage reaches depolarization threshold: stop action potentials by blocking v-gated channels. Three phases of action potential: rapid depolarization peak. V-gated na+ channels opening: falling repolarization phase. Delayed rectifier k+ channels opening: undershoot/afterpotential. Na+ channels closed but k+ still open, slowly closing.