What do synaptic knobs manufacture when an electrical impulse reaches the end of an axon?

When an electrical impulse, or action potential, travels along an axon and reaches the synaptic knobs (also known as presynaptic terminals), it prompts the release of neurotransmitters. These neurotransmitters are crucial chemical messengers that transmit signals between neurons at synapses.

Upon reaching the synaptic knobs, the electrical impulse triggers the influx of calcium ions, which initiates the process of exocytosis. During this process, neurotransmitters stored in vesicles within the synaptic knobs are released into the synaptic cleft – the small gap between the adjacent neurons. These neurotransmitters then bind to receptors on the postsynaptic neuron's membrane, leading to a propagation of the signal.

This mechanism of neurotransmitter release is essential for various physiological functions, including mood regulation, motor control, and cognitive processes. The synaptic knobs do not primarily manufacture hormones, proteins, or enzymes for the core function related to the initial transmission of signals between neurons. Instead, their primary role in this context is the synthesis and release of neurotransmitters, solidifying their importance in neural communication.