The following figure shows the axon terminal and synapse. What is the function of $P$?

Define/Explain the following terms:
$(1)$ Synapse
$(2)$ Node of Ranvier

The chemical causing the transmission of nerve impulse across synapses is

Which of the following is released by the parasympathetic nervous system?

Which of the following substances leads to the inhibition of the central nervous system?

Which of the following statements is correct regarding electrical synapses?
$I.$ Pre and postsynaptic membranes are in very close proximity at electrical synapses.
$II.$ Electric currents are involved in the transmission of impulses.
$III.$ Transmission of an impulse across electrical synapses is very similar to impulse conduction along a single axon.
$IV.$ Impulse transmission is always faster in electrical synapses than across chemical synapses.
$V.$ Electrical synapses are rare in our system.
The correct option is: