Arrange the events of synaptic transmission in the correct sequence. (1) sodium ions diffuse into the cell and cause a local potential (2) neurotransmitter binds with receptor on postsynaptic cell (3) neurotransmitter diffuses across the synaptic cleft (4) membrane permeability to sodium ions on postsynaptic cell increases (5) action potential causes release of neurotransmitter A. 5, 2, 3, 4, 1 B. 5, 2, 3, 1, 4 C. 5, 3, 4, 1, 2 D. 5, 4, 3, 2, 1 E. 5, 3, 2, 4, 1

E. 5, 3, 2, 4, 1

Explanation:

The arrival of action potential   usually causes influx of calcium ions at the pre-synaptic neuron. This leads to  the migration of vesicles containing  the neurotransmitters to the tip of the postsynaptic membranes and the release of their containing neurotransmitters into the synaptic cleft.

The neurotransmitter diffuses across the cleft, to bind with the post synaptic receptors on the membrane of  post synaptic  neuron. This increases the opening of Ligand gated sodium channels;leading to influx of sodium ions into the post synaptic  neuron. This causes depolarization, and few sodium  gated channels opened initially, but with time more channels open amusing the intensity is sustained .

Local potentials  are  generated due to influx of sodium ions, and if these potentials are summed together, and the voltage up to  the threshold level 'it  leads to generation of EPSPs  Exicitatory Post-Synaptic Potentials or or IPSPs, depending on the type of neurotranmitters in the vessicles