$GABA$ (Gamma-aminobutyric acid) is a:

What is the reason for the unidirectional transmission of nerve impulses through a synapse?

Select the incorrect option for electrical synapses.

Five events in the transmission of a nerve impulse across a synapse are given below:
$a.$ Certain ion channels open,allowing ions to enter and generate a new action potential in the post-synaptic neuron.
$b.$ Neurotransmitter molecules bind to receptors on the post-synaptic membrane.
$c.$ Synaptic vesicles fuse with the pre-synaptic membrane,and the neurotransmitter is released into the synaptic cleft. Depolarization of the pre-synaptic membrane is induced.
$d.$ An action potential reaches the axon terminal.
What is the correct sequence of these events?

Identify the location and function of the following structures:
$(1)$ Synaptic Knob
$(2)$ Bipolar nerve cell

The joint between the axon of a neuron and the dendrite of the next is called: