Synaptic knobs, also known as synaptic terminals or boutons, are located at the ends of axons in neurons. They are found at the junction between neurons, specifically at the presynaptic side of a synapse where communication occurs.
In the nervous system, when an electrical signal travels down an axon, it reaches the synaptic knob. This is where neurotransmitters are stored in vesicles. Upon arriving at the synaptic knob, the electrical signal triggers the release of these neurotransmitters into the synaptic cleft, allowing communication to occur with the postsynaptic neuron or target cell.
Thus, synaptic knobs play a crucial role in transmitting signals throughout the nervous system, facilitating the complex interactions that govern bodily functions and responses.