r/europe • u/TheRealMykola • Jan 25 '23 • 1 1 1 1 1

Little fish can overcome the greatest of odds with the right friends. Слава Україні. Political Cartoon

43.7k Upvotes

74% Upvoted

910

Russia should have been a blow fish, all pumped up with nothing but air

445

u/my_soldier Jan 25 '23

Not dissing you, but a pufferfish blows itself up with water. Blew my mind when I first realized this.

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u/afito Germany Jan 25 '23

To continue the not dissing but where did you think the air was coming from?

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u/EpicCleansing Jan 25 '23

I think it's just a classic case of wrongful association. We are used to things being inflated by air, to the point where the conceptualization is almost entirely subconscious.

It's very common. We all do it for different things. That's why we all also have a habit of interrogating the context of our ideas when we need to make important decisions, since our prejudiced/automatic conceptualization can often be ridiculously incorrect.

We all do it.

A hopefully pedagogical challenge: In your mind, what does the blood-brain barrier, that filters out all large and polar molecules from entering the brain, look like? True but misleading hint: The blood-brain barrier consists of a thick and tightly-packed layer of cells that large molecules, and molecules that aren't "oily" enough, cannot pass through.

Hordes of very intelligent medical students, pharmacists and bioengineers get this wrong.

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u/swni Jan 25 '23

I'm curious, what is the wrong idea of what the blood-brain barrier looks like?

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u/PvtKASA Jan 25 '23

I think he means that blood-brain-barrier at first sound like a place where all blood going into the brain ist filtered and then the cleaned blood is used in the brain, while after a quick google it sounds like the blood-brain-barrier is basically a coating over all surfaces of the brain exposed to the blood. So the blood in the brain is exactly the same as somewhere else in the body, but it is filtered at the contact to the cells of the brain.

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u/DimensionShrieker Jan 25 '23

noone thinks that BBB is filtering blood... it would not be called "BARRIER" but filter if it was filtering blood

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u/PvtKASA Jan 25 '23

But it is filtering blood, just not in the way I described in the first sentence. It’s job is to stop harmful substances from getting to the cells of the brain, while letting through nutrients and oxygen. What would you say the blood-brain-barrier is doing?

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u/DimensionShrieker Jan 25 '23

stopping blood from direct access to the brain cells? Pass only nutrients but nothing that is normally in blood including blood

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u/EpicCleansing Jan 25 '23 edited Jan 25 '23

All capillaries are lined with epithelium that only allows oxygen, glucose, nutrients and hormones to enter from the blood to the receiving tissues. The capillary epithelium therefore is a semi-permeable barrier, or a filter if you will. But some organs are more sensitive, and they need extra protection from certain molecules (hormones, neurotransmitter precursors, waste products, as well as toxins et.c.) which are also circulating in the blood.

The brain is one of these extra-sensitive organs. So the capillaries in the brain have a thicker epithelial wall, making it more difficult for large and polar molecules to pass through (polar molecules indicate that they may be waste products, because metabolism often works by adding polar functional groups to otherwise non-polar molecules). This extra thick layer is what is meant by the concept blood-brain barrier.

I also wrote some stuff here to the same effect.

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u/13MasonJarsUpMyAss Jan 25 '23

If it lets nutrients lass, but stops blood.... sort of reminds me of something. A filter, perhaps?

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u/DimensionShrieker Jan 25 '23

or a barrier that does not let blood in?

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u/13MasonJarsUpMyAss Jan 25 '23

Doesnt allow blood, allows nutrients

Could certainly be described as filtering, even if it doesnt work like your typical filter

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u/DimensionShrieker Jan 25 '23

I suppose so, but blood barrier to me invokes that it blocks the blood, doesn't say that it blocks everything

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u/EpicCleansing Jan 25 '23

A filter is exactly what it is. In fact it is a highly selective filter, which comes at a huge cost. It's the way that it works that is the subject of many misunderstandings.

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u/Ruthrfurd-the-stoned Jan 25 '23

Luckily it’s not selective enough so drugs go brrr

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u/EpicCleansing Jan 26 '23

Drugs need to be small and non-polar to pass through. A major and very basic part of the design of drugs is to address the BBB.

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u/EpicCleansing Jan 25 '23 edited Jan 25 '23

I guess that there are infinite wrong ideas, but I think a very common conception is that there is basically a plug in the arteries that "lead to the brain" which acts as this filter, the blood-brain barrier.

In reality, all blood vessels throughout the body are lined with epithelial cells. Medical students know this, and in fact it's true for all organs - epithelial cells are organ lining. Now, delivery of oxygen, nutrients and hormones to the cell is not done by arteries, but by capillaries. Arteries distribute blood throughout the body; this blood then eventually leads to capillaries; and capillaries deliver blood content to receiving tissues.

Arteries always have a thick epithelium, otherwise they would burst or leak. But capillaries need to have a thin epithelium, so that blood content can pass to the receiving tissues. But in certain sensitive organs, most notably the brain, the capillaries have an extra thick layer of epithelium. (Note the emphasis -- the capillaries in the brain are lined with the barrier, not "the brain" itself.) The purpose is to filter a wider portion of bad stuff from entering the sensitive tissue. This then has to be offset by adding more capillaries, so enough oxygen and nutrients can enter the organ.

The idea of a plug in the artery is completely preposterous when you think about it. But lots of smart people just use their deeply-internalized knowledge about fluid running through a hose, and running through a filter at the end, to come up with what is essentially a physical impossibility. Despite technically having contextual knowledge that should steer them correctly.

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u/swni Jan 25 '23

I see, I guess a blood-brain "barrier" sounds to me like it has to be located between blood and the brain (i.e. the walls of blood vessels), so I wasn't in danger of that particular misconception.

(What surprised me on googling is that some other organs have blood barriers as well. Also the ventricular system is fairly confusing to me.)

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u/EpicCleansing Jan 26 '23

Yes, the way we conceptualize things can be very different. I guess you're thinking the same way as the person who named the concept!

And exactly, essentially the "barrier" of epithelium lines all capillaries, so it protects all tissues in the body. Again, the difference is just in thickness of the epithelium, with certain organs having very thick barriers.

As someone with abnormally large ventricles, I'd love to learn more about the ventricular system. As far as I know, our understanding of the implications of pressure in the CSF is very low, with some results that seem to contradict theory here. It's fascinating that something like empty sella often (perhaps usually) doesn't come with any kind of symptoms or change in life outcomes.

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u/Fsaeunkie_5545 Jan 25 '23

Haha, thank you that was really nice. I always wondered how the blood-brain barrier looks like but I was never bothered enough to look it up. I did now and it makes complete sense although it doesn't have much to do with the common idea of a barrier

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u/turboultra Jan 25 '23

Reminds me of physics class, when the teacher asked what was between the electrons and nucleus of an atom, and a student responded “air”.

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u/EpicCleansing Jan 25 '23

Which is a perfectly well-reasoned given everything we've learned about physics up until that class.

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u/DervishSkater Jan 25 '23

Damn, y’all missed out on some serious water balloon fights.