Evolved Redundancy and Collateral Circulation

Brains are high maintenance organs. They require lots of oxygen, glucose, and protein in order to function at optimal levels. This is why your brain’s first priority is always itself. To make sure that there are no snafus when it comes to blood flow, we evolved some interesting artery placement in our brains. You know it as the Circle of Willis, a collection of blood vessels that looks like a little guy, meant to get the brain whatever it wants.

circle of Willis necklace in sterling silver - science jewelry

The Choke Hold

One of the worst things that can happen to a brain is oxygen deprivation. If you’ve ever taken a martial arts class, you know what we’re talking about. Putting someone in a choke hold doesn’t block their airways, it stops the blood from going to the brain. If you’re well trained, a choke hold will have your opponent tapping out … or passing out in a matter of seconds.

Strokes and the Circle of Willis

Martial arts aside, oxygen deprivation or strokes can happen without warning. Either a blood clot or a broken blood vessel can cause a sudden loss of circulation to parts of the brain. Symptoms include paralysis, numbness, confusion, dizziness, and loss of balance. Now, we know this sounds scary, but your brain isn’t completely defenseless! The Circle of Willis evolved to allow blood to flow through all parts of the brain, even if one vessel is blocked. This type of redundancy is called collateral circulation. You can think of it as a backup plan for blood flow in the brain.

A Great Backup Plan

Since May is stroke awareness month, we thought we’d pay special attention to this amazing feat of evolution, the Circle of Willis. While not all strokes are preventable, it’s good to know that aside from healthy living, evolution has done its part to make sure our brains are well-nourished. To celebrate the engineering wonders of Mother Nature, we present to you the Circle of Willis necklace. Yes, it’s the perfect gift for stroke survivors and healthcare workers helping those recover from strokes. But it’ll also be great for engineers who always put a backup valve in their designs.

written by Science with Evie 


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