Our nervous system is made up of specialized cells called neurons. These cells can talk to each other! They send signals from the central to the peripheral nervous system. But they don’t connect in one long string! Instead, the signals have to go through gaps called synapses. They do this using neurotransmitters!

An illustration of a brain neuron.

Each organ has unique types of cells. These are brain cells, called neurons.

What Are They? 

Neurotransmitters are kind of like chemical messages! They help carry data between two neurons. We need them because neurons send electrical signals down their axons. But between two neurons is a tiny gap or a synapse. Action potentials can’t travel across this gap! So these chemicals help bridge the gap. 

An illustration of a synapse between two neurons.

Neurotransmitters are chemicals that send signals from one neuron to another.

How Do They Work?

The chain starts with an action potential. When it gets to the end of a neuron, it can’t go any further. So it causes a release of neurotransmitters! These are normally stored in small sacs called vesicles. When released, they burst and release the chemicals into the synapse.

Neurotransmitters then move to the next neuron. There, they bind to receptors on the neuron! Only specific ones can bind to each type of receptor. It’s like a lock and key! If you have the wrong key, it won’t open the lock. So if you don’t have the correct neurotransmitter, the data won’t send! 

An illustration of a synapse and the chemicals moving from one side to the other.

These chemicals have to bind to the next neuron!

If the chemical isn’t used up, it can actually be recycled! The cell can pick it back up and reuse it. 

What Do They Do?

Different neurotransmitters have different jobs. There are 2 main types: excitatory and inhibitory. The names kind of give you all the information you need! Excitatory types make a response more likely to happen. They do this by triggering depolarization. This makes the inside of a neuron less negative! 

Inhibitory types do the opposite. They make a response less likely to happen. They cause hyperpolarization to happen! The neuron becomes more negative. This reduces the chance that a signal will send.  

An illustration with percentage signs, one red with an arrow down and one green with an arrow up.

These chemicals can either lower or raise the chance that a response happens!

Types of Neurotransmitters

There are many kinds of these special chemicals in our bodies. Here are just a few examples! 

Dopamine: This affects pleasure and happiness. There are parts of our brain that are tied to motivation! It can work as both an inhibitory and excitatory neurotransmitter. But beware. Lots of drugs work by increasing dopamine in our brains. Then your brain can forget how to make you happy!

Serotonin: This is another happiness related, excitatory neurotransmitter! Aside from well-being, it helps manage our mood and anxiety. Serotonin is also heavily tied to sleep!

An illustration with the names of the hormones that affect happiness.

These chemicals regulate our feelings of happiness!

Glutamate: This is the most common of these chemicals in our body! Glutamate is an excitatory neurotransmitter that helps us learn and create memories.

Acetylcholine: Another excitatory neurotransmitter, it works in the parasympathetic nervous system. This is the part of the nervous system that works when you’re resting. It helps you save energy and revs up the digestive system!