BIOB34H3 Chapter Notes -Voltage-Gated Potassium Channel, Threshold Voltage, Tandem Pore Domain Potassium Channel
Document Summary
Graded potentials depolaraizations or hyperpolarizations that occur in the dendrites and cell body (or sometimes in the axon terminals: the changes in membrane potential have an amplitude directly proportional to the strength of the triggering event. What causes graded potential: in the cns and the efferent division, chemical signals from neurons open chemically gated ion channels. Allows ions to enter or leave the neuron: in some sensory neurons, a mechanical stimuli (e. g. stretch) opens or closes ion channels. Closing ion gates can cause depolarization too: e. g. closing the k+ gate and retaining k+ Figure 8. 7 show graded potential where: a stimulus opens a monovalent cation channel allowing sodium influx, positive charge sends a wave of depolarization through the cytoplasm. Local current the wave of depolarization that moves through the cell. Convention: current is the net movement of positive electric charge: initial amplitude (or depolarization strength) in a graded potential is determined by how much charge enters the cell.
