Betcha you didn’t know you have a second brain. It takes care of business so the brain in your cranium doesn’t have to think much about… things. It’s called the Enteric Nervous System (ENS), a.k.a. the intrinsic nervous system, or the second brain. With a half-billion neurons, the ENS is bigger than the primary brain of many small animals. In contrast, the human brain consists of around 100 billion neurons.
Somewhat like a computer (if you’ll pardon the analogy), your primary brain is the central processing unit (CPU) that your mind runs on: it does all the hard work, most of the time doing multiple things simultaneously. Meanwhile, your ENS is like a microcontroller in the computer which does one thing only, such as controlling a hard drive efficiently so the CPU doesn’t have to be bothered with such trivialities. The CPU and the microcontroller communicate with each other, of course. The CPU asks the microcontroller for information from the hard drive, for example, and the microcontroller makes it happen. Overall, the microcontroller operates autonomously from the CPU. That is, it does its job without being told how to do it by the CPU. This arrangement reduces the CPU’s workload by offloading the task onto the microcontroller. The ENS works similarly, running important things downstairs while your big brain upstairs concentrates on weighty matters, such as what to have for breakfast. So what, exactly, does the ENS do? What is its job?
Your ENS is in charge of all gastrointestinal (GI) functions. It autonomously runs the digestive system. The 500 million neurons that comprise the ENS are spread throughout your digestive system. Some of these neurons are sensory in nature, whose sole purpose is to sense conditions in the GI system. If your guts aren’t happy, the ENS communicates that information through something called the vagus nerve (no, nothing at all to do with Vegas, baby) to your big brain, and suddenly you aren’t feeling well, either.
Other neurons coordinate the muscles surrounding the intestines. The muscles contract or relax on command of the ENS, without any input from your cranial gray matter. The ENS propels food through the intestines, which is critically important to survival. If food doesn’t move through the gut, nutrients can’t be absorbed, and then where would we be? Not in a good place, that’s for certain.
The gut may be the least studied, least understood organ of the body. However, right now there’s quite alot of interest in this critical system and exciting new things are being discovered everyday. For example, in recent years we’ve learned the health of the gut and microbiome is paramount to our immune system. It directly effects how long we live, how healthy and youthful we remain as we age. It also has a direct effect on our emotions and mental health. There’s lots of evidence that brain health is inextricably linked to gut health.
The gut/microbiome complex is a vital, yet mostly overlooked component of the human body, and it’s run by the ENS, your second brain. Betcha didn’t know.
“DITW – The Enteric Nervous System” (2:15)
Duke University – “The Gut-Brain Connection” (2:02)
Question Of The Night: What do you like for breakfast?