Spatial and Temporal Summation
Trigger zone
The graded potentials combine at the _____ _____ of the postsynaptic neuron
Threshold
A single postsynaptic potential is usually not strong enough to reach _____
Action potential
If the combination of graded potentials reaches or exceeds threshold at the trigger zone, an _____ _____ is produced
Graded potentials
Many _____ _____ are produced in the postsynaptic membrane at a given time
Combined summation
Occurs when spatial and temporal summation occur at the same time
Temporal summation
Occurs when two or more graded potentials are produced at a given location on the neuron's cell body or dendrites in such rapid succession that they can summate at the trigger zone Increase in frequency
Spatial summation
Occurs when two or more graded potentials from different locations on the neuron's cell body or dendrites reach the trigger zone simultaneously Increase in number across the cell
Na+
The trigger zone has a concentration of _____ channels that is 7x greater than elsewhere on the cell body