Brain & body: the gut brain connection

Welcome back to the buzz, the brain buzz. Last week we highlighted a part of the brain that helps us make or break habits. If you’re looking to do either of those, click here to learn how. 

Now, it’s time to move on to a new brain structure, one that doesn’t get as much love as the big gray squishy structure with all of the strange folds, the structure that pops into your head when you hear the word ‘brain.’ 

The formal name for this attention grabbing part of the brain is the cerebrum. The sad thing is that we tend to forget the parts of the brain that lie below and support the big, gray squish. One of these supporting players is the brain stem.

The brain stem is one of the oldest, most important parts of the brain that does all of the work we need to live, like maintain vital control of the heart and lungs and coordinate our reflexes. The brain stem works for us even when we don’t realize. That’s because it’s part of the autonomic nervous system, the system in the body that works for you. No thinking or effort required.

This part of the brain tells your body to breathe, your blood to pump.

Let’s all give a big thank you to the brainstem.

So, how does this happen? Well, the brain stem is like a train station.


Imagine this…

In the brainstem there are several trains waiting on their respective tracks. At certain times, a train will take off down its tracks after receiving a signal and go to another train junction to relay message.

Trains also go back up to the brainstem station from train junctions all around the body, giving the brainstem feedback and keeping everything in check.

Instead of train tracks, what we have in the body are nerves. These nerves carry signals from our brainstem to different parts of our body that help us move, feel, and react.

Let’s take a quick pause and talk about what a nerve is. Essentially, it’s a really long neuron, or brain cell.

Tour time! Through the neuron we go…

The neuron has a couple main components: The axon, the soma, & the dendrites. There’s a lot more to a neuron, but these are the macro players.


The axon is the long skinny part of the neuron where the electrical pulse gets sent. The axon also receives the signal from the dendrites, the tree-like branches of the neuron. The dendrites job is to send the signal. The soma is the cell body of the neuron, where all of the micro cell parts are located, such as the nucleus, mitochondria, ribosomes, you name it.

Now, let’s take a step back and look at the overall nervous system. The overall nervous system is like a network of wires, transmitting electrical activity from one part of the body to the next. But guess what… A nerve that runs all throughout your body is made of one big, longgggg axon of a neuron, interweaving and mingling with other long axons.

So, in a sense, your brain is in your whole body.


Whoah. Have you ever thought of your brain like that?

Probably not. They don’t teach you that in school. But the beauty of looking at it this way is that it helps you realize that everything is connected.

And the brainstem helps you make these connections 🙂

One of the most fascinating nerves that facilitates the brain/body connection is the vagus nerve, otherwise known as the tenth cranial nerve.

The vagus nerve is the longest and most prolific nerve in the body! It travels to many parts of the body, including the heart & the lungs. I’ve also written an article about the heart-brain connection, check it out here if you’re interested.

screen-shot-2016-10-25-at-09-59-10Thanks to the brainstem & the vagus nerve, we have what’s called the “gut-brain connection.”

Don’t you remember your mamma telling you that it’s all about connections?

Your mamma is a wise woman.

In particular, the vagus nerve creates a connection from the brain to the enteric nervous system.

The what?! Another nervous system? Yep, betcha never heard of this one. The enteric nervous system is a system of nerves that exist inside your digestive system.


This system actually has more neurons in it than in the brain! There are neurotransmitters and other brain chemicals in your gut as well. Told you your brain exists in your whole body.

Ok, so back to the brainstem. Like I wrote, the brainstem both sends and receives signals through different nerves. Efferent nerves send the signals from the brainstem to the body and Afferent nerves send the signals from the body to the brain.

It’s a bit hard to remember, but just try to think, Afferent = Away from the body & to the brain.

The afferent signals give the brainstem sensory information, meaning it tells the brainstem how the organs are doing. The brainstem then sends that signal up to the higher parts of the brain for further processing. So, the brainstem will tell the brain when the gut isn’t doing so well.

Scientist have yet to know what this means. What exactly does this do to the brain? When the digestive system isn’t working well, does that mean you have a greater risk for Alzheimer’s, anxiety, or Parkinson’s Disease?

We don’t quite know yet.

Also, you could look at it from the other direction. If you have a brain malfunction does that mean you have a greater risk for a digestive problem?


When it comes down to it, the answer is yes. The answer is yes because everything is connected. The whole entire body is affected when just one part of the body is feeling a bit off. 

Whether the effect is large enough to make a noticeable difference is unknown.

That’s why we need more curious people to go out and find the answer to these questions!

For now, hopefully you take away these two things:

  1. How awesome your brainstem is. Give some attention to this part of your body that never stops working. Gratitude goes a long way. And…
  2. The whole body is interconnected, so in order to give your brain a little love, give the rest of your body a little love as well. I have some concrete advice for you on how to do this. You can check it out here…
    1. How to breathe your way to happy brain waves
    2. The grocery list for a better brain

For questions, be like the neuron, send us a signal and we’ll reach back.

From my heart & brain to yours,


Hannah Heimer
Hannah Heimer

I’m a brain enthusiast and yoga fanatic. I work as a researcher at the University of California, San Diego while also running a yoga business on the side.

I use brain research and yoga as a springboard to blog about lifestyle, health, happiness, and how it all relates to your brain.

Just like the nerve cells in our brains, I love making new connections. So, feel free to reach out. For more info on yoga and the brain, take some time to explore