BIO 12 Lecture Notes - Lecture 8: Membrane Potential, Axon Terminal, Resting Potential
Document Summary
Open or close in response to stimuli. Determine whether an action potential will occur. One presynaptic neuron releases neurotransmitter many time over a period of time. Multiple presynaptic neurons together release enough neurotransmitter to exceed the threshold of the postsynaptic neuron. Excitable membranes have the ability to generate action potentials. Travel along axons from cell body to axon terminal. Nerve cells and electrical signaling action potentials. Depolarization: voltage gated na+ channels start to open (-55mv, voltage gated na+ channels are inactivated once +30mv. Pk > pna: membrane potential close to ek, membrane potential far from ena. Rapid opening of na+ channels: regenerative mechanism. Slow opening of k+ channels: opening of k+ channels and the closing of na+ channels is the reason that the action potential do not reach ena. K+ channels opened: k+ channels remain open beyond the resting membrane potential; k+ continues to leave, membrane potential gets close to ek hyperpolarization.
