What Exactly Is the Blood Brain Barrier?

Our brains are choosy about what they let in, and that's thanks to the blood brain barrier. In this episode, Patrick explores how this anatomical separation between our blood and brain keeps us safe from potential harm.

The heart pumps oxygenated blood through arteries into systemic circulation, then those arteries branch out into tinier and tinier blood vessels called capillaries that surround different tissues. Capillaries have really thin walls, and oxygen, carbon dioxide, and other compounds can diffuse through those walls to get in or out of the blood stream.

And just like any other organ, the central nervous system, which includes the brain and spinal cord, gets oxygen and nutrients from the blood. But these organs are a little more sensitive to changes in their direct environment, so they need a bit more security around their blood supply to keep themselves stable. That’s where the Blood Brain Barrier comes in.

It’s an anatomical separation between the brain’s capillaries and the fluid between brain tissue itself. It’s made of a few different structures including special endothelial cells, a sheath of connective tissue, and nervous tissue that surrounds those tiny blood vessels in the brain. This thing is purpose built to be a selectively permeable barrier, so let’s take a little tour, starting with the inside of the capillaries.

#bloodbrainbarrier #human #physiology #seeker #humanseries

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The Blood Brain Barrier
“More than 100 years ago it was discovered that if blue dye was injected into the bloodstream of an animal, that tissues of the whole body EXCEPT the brain and spinal cord would turn blue. To explain this, scientists thought that a "Blood-Brain-Barrier" (BBB) which prevents materials from the blood from entering the brain existed.”

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This Seeker health series will dive deep into the cellular structures, human systems, and overall anatomy that work together to keep our bodies going. Using the visual structure and quick pacing of Seeker’s Sick series, these human bio-focused episodes will give a new audience an inside look on what’s happening inside all of us.

[axem.]

How is my body so efficient, competent and amazing and I am none of those!

[umarscamartistjohnson]

*didn’t know I needed to watch at 7:30 A.M.* I’m not complaining though...

[iadtag]

Those cells sounds like they do way soooo much work! I'm glad there's still a part of me that's actually competitively productive.

[mudfossiluniversity]

I study this and the vascular system in general. The problem is strokes create BIG STUFF like scabs in the brain that cannot get out. Enterecept injected ABOVE the BBB can recover some stroke people in 10 minutes.

[medmom]

The connection to depression and microglial cells is fascinating as well, do you have a video on that?

[birb]

All this protection, and yet when you smoke DMT the brain says “GIMMIE” and actively transports it across the barrier.

[reinaldomartinez]

I used to imagine a "filtering" layer that allowed "filtered" blood to pass. But it is more a multi-dimensions boundary sorrounding the vasculary system deep inside the brain. And it makes perfect sensne. I guess my previous visualization did not made sense, where would the filtered (rejected) material go and how (a brain liver LOL). Thanks for the explanation, I learned something today.

[sanicanadkarni]

Great a medical student, it was very nicely explained

[Melissa]

Does the blood brain barrier ever get messed up from surgery, from the cells actually being physically cut into?

[DaBlondDude]

I had to pause to go look up what endothelial cells are lol.
Is there a difference between these cells in the brain vs elsewhere?
This also sparks my curiosity about how some germs can pass through that barrier.

[akshaykn]

Patrick kelly is a genius, , keeps things really simple and organised.

[macbuff]

Ultrasound is also used to temporarily widen the paths so to allow drugs to pass through the barrier

[Biociety]

I often hear that term, but never looking how it works. Thanks for the explanation!

[eibyweno]

discuss how the structure of the BBB prevents the entry of some molecules but allows others through

[sabeeldhanish]

Incredible engineering of brain. Mind blowing

[anshajkumar]

More in a video than what i learned in biology whole this year

[vermeerasia]

Guys -- lose the background music, please. It distracts from the material and adds nothing positive.

[RaymondDay]

You should of added that's why we have to sleep to clean out what bad gets through to the brain.

[tamanna]

The way I was taught this, I was told that the neurons are highly differentiated and hence the leucocytes can’t recognize them as a part of its own body so the immune system might attack the neurons if it comes directly in contact with them. This is why the blood brain barrier exists

[jameswilliams]

The absolute Shear wisdom of our creator is amazing