What does the synaptic knob comprise?

Synaptic knobs:

1. These are also called synaptic terminals.
2. These are the ends of the neuron that are associated with the signaling of the neuronal impulses.
3. Synaptic knobs contain hundreds of membrane-bound synaptic vesicles.
4. Synaptic vesicles are 40 to 100 nm in diameter and contain a specialized chemical messenger called a neurotransmitter.
5. Neurotransmitters such as serotonin, dopamine, and epinephrine are the body's chemical messengers.