Neural Control & Synaptic Transmission — NEET Biology

Correct answer: C — S2, S4 and S6

Synaptic transmission involves the transfer of nerve impulses from one neuron to another across a synapse. S1: Impulse transmission across an electrical synapse is always faster than that across a chemical synapse because current flows directly. This statement is correct. S2: The synaptic cleft, a fluid-filled space, separates the pre- and post-synaptic neurons only in chemical synapses. In electrical synapses, the membranes are in very close proximity. Therefore, this statement is incorrect. S3: When an action potential arrives at the axon terminal of a pre-synaptic neuron, it stimulates synaptic vesicles to fuse with the membrane and release neurotransmitters into the synaptic cleft. This statement is correct. S4: The binding of neurotransmitters to receptors on the post-synaptic membrane can generate either an excitatory or an inhibitory potential, depending on the neurotransmitter and receptor type. It does not always generate an excitatory potential. Therefore, this statement is incorrect. S5: Transmission of an impulse across electrical synapses is indeed very similar to impulse conduction along a single axon, as electrical current flows directly. This statement is correct. S6: The endocrine system provides chemical integration through hormones, while the neural system provides point-to-point connections for quick coordination. Therefore, this statement is incorrect. The statements that are NOT correct are S2, S4, and S6. Therefore, option C is the correct answer.