Synapses are the connection between neuron to neuron throughout our body. Without synapses, our everyday thoughts could not turn into action. The thought of picking up your phone, for example, would not be possible unless that message didn’t travel from our brain to our muscles. This article gives a brief and basic introduction to the role synapses and neurons play in sending signals through our body.
For simplicity: think of a synapse as a bridge between two islands. Just like a bridge allows for the passage of people and goods between two pieces of land, a synapse allows for the passage of neurotransmitters between two neurons.
However, unlike how a bridge comes in contact with two land masses, synapses don’t touch the two neurons they connect. The synapse simply acts as a junction for two neurons to communicate.
Image via simplypsychology.org
As seen in the illustration above, the synapse connects two neurons and allows for the passage of electrical impulses. The neurons themselves contain their own parts. Take the soma, for example — this is known as the cell body of the neuron, and acts as the command center. Think of it like the headquarters of a business. It provides energy to drive the neuron’s responsibilities, provides support to the neuron’s structure, and contain’s the neuron’s DNA within the nucleus.
Then there is the axon, the long tail-like structure you see in the image. Axons are conductors of electrical signals, kind of like a highway the impulse travels through to get where it needs to go.
These electrical signals are sent down the axon using something called an action potential. An action potential is triggered by charged particles known as ions moving in an out of the neuron’s membrane. Imagine a balloon: this is the neuron’s membrane. When air flows into the balloon, it inflates, and when air flows out, it deflates — the balloon either gets smaller or larger. This is similar to how ions flow in and out of the neuron membrane.
The size of the balloon represents something called the “membrane potential”. When a balloon inflates or deflates, it changes size — similarly, when ions move into a neuron’s membrane, the membrane potential increases, and when ions leave the membrane, the membrane potential decreases. If enough air flows into the balloon, the balloon will eventually pop. In other words, when there’s a significant change in the membrane potential in the neuron, an action potential will be triggered, starting the journey of an electrical signal.
As the electrical signal reaches the end of the axon, it approaches the synapse, which releases neurotransmitters that help transmit the electrical signal to the next neuron. The neurotransmitter crosses the synapse and binds to the receptors of a dendrite. The dendrite is the branching segment of a neuron that receives signals from other neurons.
Without triggering the release of a neurotransmitter by the synapse, there would be no electrical signal traveling to other neurons. The synapse acts as the middle man between two neurons and makes sure the signal crosses. Without the coordination between neurons and synapses, we wouldn’t have been able to pick up our phone, lift a mug, run, walk, or even think. Synapses are crucial to our life as we know it and helps to ultimately ensure the simplest of our body’s functions are conducted effectively.
This was only a brief explanation of synapses and the role they play in neurons, and there is so much more to what they do — for more information on neurons and synapses, here are some resources: