Blood Brain Barrier: Learn Integral Anatomy with Gil Hedley

in this video I'd like to discuss the difference between the blood flow through the brain and through the liver particularly about the blood-brain barrier so many people are curious about and I'm bringing the liver into the story because basically the liver and the Brain live on opposite sides of a Continuum of capillary structure so capillaries are the TC tiny little part of your blood flow system of your heart tree which starts out with big old arteries and big old veins and ends up at the periphery with TC tiny little Pathways that we call capillaries and I've drawn two different types of capillaries here on the board now red blood cells flow literally one by one through a capillary that's how small they are because red blood cells are really tiny so in the liver I hope we have what are called fenestrated or sinusoidal fenestrations big fancy word for got holes in it so a fenestra is like Italian or Latin for a window so the capillaries of the liver have Windows in them now why is that because in places like the liver and say the spleen as well we have these sinusoidal fenestrations because those organs are basically filters of the blood so as a little red blood cell goes tumbling along through a liver capillary it literally falls out of it like like water through a colander and splashes about on the tissues of the liver which is like a sponge soaked with blood whose you know chemical intelligence processes that blood and other substances in the blood in a way that ultimately say breaks down toxins and protects us from them or sequesters those toxins into the bile and excretes them so very handy that the capillaries of the liver are fenestrated meaning having Windows through which lar relatively large structures like a blood cell can pass through the epithelial lining and through veritable holes in the wall for them to be processed now the brain is the total opposite of that the blood-brain barrier uh is basically describing the structure of the capillaries of the brain so the structures of the capillaries of the brain are featuring very tight Junctions in epithelial lining cells or the endothelial lining cells of the capillaries of the brain so look there's no way out of this thing so how does anything get through well the red blood cells don't get through much smaller things can pass through you know gases and ions and such and if something larger some kind of protein has to get through or whatever it's mediated by transporter proteins that are like bouncers at the bar so this bar is like anybody can come in it's some kind of Speakeasy and there's no there's no no limits to what can pass into the bar of the liver but the bar of the brain has got it's got bouncers standing around there like you're not going in there you're not going in there uh well you can come in but we're going to hook arms and I'm going to literally walk you into the bar so that's how you get across these tight junctions or there's also you know chemical events that can be communicated through the blood that actually will for certain substances sort of loosen the tightness of the Junctions and allow things to squeeze through so it's very specific oddly alcohol gets a pass so this is the funny thing about drugs and alcohol some of them their effect is possible because of the ease with which they pass through these tight junctions despite the brain's best efforts so we can have the passage of certain things through here that affect the brain in all kinds of crazy ways because they can transport themselves across the blood-brain barrier it's like it's like they go to the bouncer hey look that way and and they're like and they go right in so blood brain barriers generally a very effective protector of the tissues of the brain from all sorts of substances that might harm it whereas the sinusoidal fenestrations of the liver capillaries are basically designed to handle those toxins specifically and break them down I think that's cool there are also structures in between these so uh it's not all exactly like that you could have say fenestrations that have kind of kind of a proteinaceous stringiness across them that makes it a little harder for stuff to come out but allows larger molecules to pass through for filtration and say the kidneys so there are you know kind of gradations between these two but I give these two as the extreme examples to help you understand particularly the blood-brain barrier thanks for watching if you'd like to study more with me go to gilheadly.com there's a ton of stuff there enjoy

Channel: somanaut

Views: 3,345

Keywords: human anatomy, learn human anatomy, cadaver anatomy, cadaver dissection, spiritual anatomy, inspirational anatomy, anatomy and physiology, anatomy tips, Gil Hedley, Integral, Anatomy, learn integral anatomy, learn anatomy, anatomy, physiology, cadaver lab, human dissection, cadaver study, anatomy study, body, studying the body, study anatomy, somanaut, sinusoidal fenestrations, fenestrated, capillaries, blood brain barrier, liver, brain

Id: gdl3Q5mHGvo

Length: 6min 5sec (365 seconds)

Published: Mon Jul 17 2023