Hypertension effects on the blood vessels | Health & Medicine | Khan Academy
Aug 24, 2023
Hypertension effects on the blood vessels | Health & Medicine | Khan Academy
Learn about how hypertension can cause damage to the large/middle sized arteries as well as the small arteries and arterioles. Rishi is a pediatric infectious disease physician and works at Khan Academy. Created by Rishi Desai.https://www.khanacademy.org/science/h … https://www.khanacademy.org/science/h …www.khanacademy.org , join us on Facebook or follow us on Twitter at @khanacademy. And remember, you can learn anything. https://www.youtube.com/subscription _…
Content
1.26 -> Now, we've talked
about hypertension,
3.43 -> and you know that it means that
you have high blood pressure.
8.21 -> So the next logical thing to
think about is why is that bad?
11.84 -> Why is it a problem to
have high blood pressure?
14.83 -> And I like to think
about high blood pressure
16.97 -> from two different
perspectives-- one would
19.6 -> be the perspective of
the heart, and the other
22.51 -> is the perspective
of the blood vessels.
24.95 -> And so here you can
almost divide it up
27.79 -> as the thing that's
making the pressure
31.84 -> or generating the pressure,
which is the heart,
35.63 -> and the thing that's
receiving the pressure.
38.02 -> So generating versus receiving
pressure, and each of these two
47.64 -> areas has some serious
consequences for the body.
52.62 -> So let's just divide it up here.
54.2 -> Let's just draw a dashed
line, divide up our screen,
59.35 -> and we'll talk about both areas.
61.18 -> So let's start with the
receiving pressure side.
63.27 -> So we have the large and
middle sized arteries--
69.29 -> and specifically I mean
arteries that are between,
74.57 -> let's say, 25 millimeters
in diameter all the way down
78.66 -> to about one
millimeter in diameter.
80.61 -> So primarily these
are the vessels
83.21 -> that are going to get
blood from the heart
84.96 -> to the different organs
that it needs to get to.
88.11 -> And then you of course have the
small arteries and arterioles.
95.45 -> And these are going
to be at the high end.
100.38 -> They're going to
be one millimeter.
101.85 -> But they're going to go
all the way down and get
103.85 -> smaller and smaller to about
0.01 millimeters, so about
106.73 -> 1/100 of the size.
108.03 -> They're very tiny.
109.62 -> And these are
receiving pressure.
111.5 -> Both of them are
receiving pressure.
113 -> These I'll draw as-- I'll
leave the drawing up above,
116.06 -> and these are kind of very,
very narrow ones, right?
119.77 -> So both of them are
receiving the pressure,
122.31 -> and they're going
to have problems.
123.85 -> So for example, if
you have, let's say,
125.69 -> a large or middle
artery that is--
128.34 -> let me draw it in
a different color.
130.31 -> Let's say here it's
very elastic-- over time
141.06 -> if you keep exposing
this elastic vessel
145.75 -> or tube to high pressures,
over time what would happen
150.13 -> is this becomes very
firm, like a pipe.
158.24 -> So that's one change.
160.34 -> And in fact, that change
from being elastic to firm,
163.2 -> we call that arteriosclerosis.
165.71 -> I'll write that in
white-- arteriosclerosis.
175.02 -> And in fact, a
very similar thing
176.71 -> happens on the other side
with the small arteries
180.046 -> and arterioles.
180.67 -> They also have very
similar kind of change.
183.44 -> They can go from being
very elastic-- I'm
186.83 -> trying to draw it so it's
got some springiness.
189.12 -> That's obviously kind
of tricky to draw.
192.89 -> These become very firm
as well over time,
196.57 -> and they lose that elasticity.
201.46 -> And when it happens in the
small arteries or arterioles,
204.26 -> we call that
arteriolosclerosis--
208.48 -> a very similar
word, but slightly
211.89 -> different-- arteriolo-- an
extra L and an O-- sclerosis.
216.795 -> So this is the
difference, right?
218.17 -> They're very similar things,
kind of similar processes,
220.84 -> but one is in the
smaller arteries
222.87 -> and one is in the larger
and middle sized arteries.
225.84 -> So this is one of
the things that
227.98 -> can happen when you have
lots of high blood pressure
230.58 -> constantly exposed
to the vessels.
233.1 -> They can become firm.
235.1 -> OK, going back to the
large and middle arteries,
237.52 -> you also can have a
situation-- I'll draw it here--
241.73 -> where you have an artery,
let's say-- actually,
244.53 -> let me write what it is first.
246.41 -> You can have an aneurysm.
248.57 -> And an aneurysm is where
you have a vessel-- let's
253.02 -> say this is my vessel, and
it's taking blood through it.
260.339 -> So blood is going through it.
261.899 -> And because of the
constant blood pressure
265.02 -> that's going
through this vessel,
266.8 -> the wall starts to get weak.
268.54 -> So at one spot, it
starts to get weak.
270.98 -> Let's say right here
instead of being like that,
274.02 -> it starts to look like this.
277.43 -> And you get this little
area of weakness.
279.95 -> I'll try to draw it like that.
281.74 -> And because it's weak, the blood
will start going, and hitting,
286 -> and bouncing off the walls, and
making it a little bit bigger.
289.33 -> So it looks like that.
290.27 -> And over time, it might do this.
292.37 -> It might become a big sack.
294.282 -> And that's an aneurysm.
295.24 -> And actually that aneurysm,
if it's a sack of blood,
298.27 -> can actually burst and break.
300.26 -> And that blood can spill out,
and we call that hemorrhage.
303.52 -> So you can actually
have an aneurysm
305.36 -> because of a weak vessel wall.
308.61 -> Now, looking at the small
arteries or arterioles,
311.49 -> you can also have,
not necessarily
313.62 -> aneurysms in the
same way, but you
316.26 -> can have breaking or hemorrhage.
319.82 -> And here I want to
show you or remind you
322.9 -> that these vessels,
these tiny ones anyway,
325.79 -> they're usually not sitting
out there on their own.
329.37 -> They're usually within an organ.
332.8 -> So this tiny vessel--
remember, it's
334.965 -> one millimeter to a
hundredth of a millimeter.
337.44 -> So it's actually sitting
inside of a kidney
340.29 -> or sitting inside of an eye.
343.62 -> And so these organs
have inside of them
348.29 -> these arterioles
and small arteries.
350.7 -> And so when they're in that
situation, if you have a break,
356.45 -> let's say-- actually,
let me rewrite this
359.86 -> slightly differently.
361.16 -> If you have a break
in the vessel,
363.3 -> we actually get organ damage.
369.8 -> So this could be because
the vessel literally
372.14 -> breaks right here
and blood spills out.
375.43 -> And it could also be because
these tiny vessels are
378.78 -> necessary to make
the organ work.
382.13 -> For example, the kidneys require
that these small arteries
385.66 -> and arterioles are
working properly.
387.55 -> And if they're not, you
start getting some problems
389.84 -> with being able to do
the job of the kidney.
393.34 -> And so you can
get kidney damage.
396.78 -> Or if it's in your eye, you can
get what we call retinopathy,
404.72 -> basically meaning that the
retina is not working properly.
411.33 -> So you can have kidney
damage or retinopathy.
413.93 -> You can have aneurysms,
arteriosclerosis,
415.94 -> or arteriolosclerosis.
417.78 -> And these are all
related to the fact
419.75 -> that the blood
vessels are breaking
422.38 -> or they're becoming more firm.
425.28 -> And this is all on the
side of receiving pressure.
Source: https://www.youtube.com/watch?v=PYkaoQc-fLU
