Question

Put the events of neural signal transmission at the synapse in the order that they occur from first to last.

First to Last

1.Action potential arrives at synaptic terminal from axon.

2.Vesicles in sending neuron fuse with the membrane.

3.Neurotransmitters are released into the synaptic cleft.

4.Neurotransmitters bind to receptor proteins on the receiving cell membrane.

5.Ion channels in the receiving neuron are stimulated to open.

6.Chance of action potential in the receiving cell either increases or decreases.

Answer 1

The options from 1 to 6 are already given in the order from first to last events that occur at a chemical synapse.

1. The action potential arrives at the synaptic terminal from axon. Then the voltage gated calcium ion channel opens, and calcium ion influx occurs from extracellular fluid to cytosol.

2. Then the calcium dependent fusion of synaptic vesicle occurs with the membrane of pre- synaptic neuron. Binding of calcium ions to a protien synaptotagmin- which leads to fusion of docked vesicles.

3.then the synaptic vesicles release neurotransmitter by exocytosis.

4. The neurotransmitters that are released into the synaptic cleft binds to the receptor protiens on the recieving cell membrane of post synaptic neuron.

5. Then those nuerotrneurotrans acting as ligand and stimulates it to open.

6. The chance of action potential in the recieving cell may increase or decrease. If the change in potential of recieving neuron is depolarizing then it is called excitatory postsynaptic potential (EPSP) or if the potential is hyperpolarising- increase in negative charge inside called as inhibitory post synaptic potential ( IPSP).