At an excitatory chemical synapse between two neurons
A)there is increased permeability of the postsynaptic cell to both Na⁺ and K⁺.
B)a small hyperpolarization of the postsynaptic membrane occurs when the synapse is activated.
C)an action potential in the presynaptic neuron always causes an action potential in the postsynaptic neuron.
D)excitation occurs because K⁺ enters the postsynaptic cell.
E)action potentials spread through gap junctions between cells.

Question

Quizplus · Accepted Answer

Excitatory chemical synapses cause depolarization of the postsynaptic neuron by increasing the permeability of the membrane to Na⁺, which enters the cell, and sometimes to Ca²⁺. This depolarization can result in the generation of an action potential in the postsynaptic neuron. K⁺ leaving the cell does not cause excitation. Additionally, gap junctions are not involved in chemical synapses.

At an Excitatory Chemical Synapse Between Two Neurons