Physiology 2130 Lecture Notes - Lecture 4: Neuromuscular Junction, Exocytosis, Axon Hillock

• School: Western University
• Department: Physiology
• Course: Physiology 2130
• Professor: Christine Bell

Document Summary

Excitable: nerve cells can use the resting membrane potential to generate an electrochemical impulse (action potential) Depolarization: during action potential, the membrane potential rapidly changes from resting (- 70mv) to roughly +35 mv, therefore it is the sudden change to a positive value. Repolarization: after this phase increase, the membrane potential returns to -70mv. Hyperpolarization: the membrane potential then briefly becomes more negative roughly - Describe what will happen when the specific ion channels open for each of the following ions. Depolarization of the membrane occurs activation gate opens immediately, na+ flow into the cell down the concentration gradient inactivation gate closes and na+ can no longer flow into cell. The channel cannot open (absolute refractory period) Gate will return to their resting configuration. Depolarization of membrane occurs (membrane becomes more positive/less negative) After a brief pause the k+ voltage-gated channels open. K+ flow out of cell- down their electrical and chemical gradients.