Answer
b. An action potential is a rapid and brief electrical signal that travels along the membrane of a neuron, allowing for communication between neurons or with other cells in the body.
a. A synapse is a junction between two neurons or between a neuron and a target cell, where information is transmitted from one cell to another.
b. At the axon terminal, an action potential triggers the opening of voltage-gated calcium channels, allowing calcium ions to enter the cell. This influx of calcium causes synaptic vesicles containing neurotransmitters to fuse with the presynaptic membrane and release their contents into the synaptic cleft.
a. If the neurotransmitter released by the postsynaptic cell is excitatory, sodium ion channels will open when it binds to its receptors. This will cause an increase in membrane potential and the cell is likely to reach threshold.
b. If the neurotransmitter released by the postsynaptic cell is inhibitory, potassium ion channels will open when it binds to its receptors. These ions will flow out of the cell, causing a decrease in membrane potential and making it less likely for the cell to reach threshold.