PSY290H5 Study Guide - Midterm Guide: Saltatory Conduction, Threshold Potential, Myelin
Document Summary
Epsp signals received in cell body or dendrites. Are graded, can integrate information over multiple connections. Ap different bc only occur in axons , occurs in rapid succession. Early part rep a depolarizing stimulus that depolarized to a threshold potential. Graded potentials exist everywhere , incl axons who haven"t reached threshold. Axons have voltage-gated channels, if current is strong enough, they open up. Mechanically gated channels deform and allow sodium ions to flood into a neuron if depolarization reaches threshold it causes voltage gated sodium channels to open up. 0. 5 ms for voltage gated channels to fully open and fully close again. Overshoot how long potassium gated channels are open for (other half millisecond) Depolarizing currents no longer have an effect absolute relative happens during undershoot - need greater depolarizing current ap less likely to happen. -axon is lined with voltage-gated channels all the way down its axon. -axon is lined with fatty sheets of tissue (myelin)
