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Health and medicine
Course: Health and medicine > Unit 3
Lesson 5: Hypertension- What is hypertension?
- Intro to hypertension (Pressure, flow, and resistance)
- Intro to hypertension (systolic and diastolic blood pressure)
- Stages of hypertension
- Hypertension types and causes
- Primary hypertension
- Secondary hypertension
- Hypertension effects on the blood vessels
- Hypertension and blood vessel damage
- Hypertension effects on the heart
- Hypertension and heart damage
- Complications of hypertension
- Hypertensive crisis
- Diagnosis of hypertension
- Treatment of hypertension
- 4 lifestyle changes to help manage hypertension
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Hypertension effects on the blood vessels
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.
Want to join the conversation?
- @Is the body able to repair an aneurysm or is surgery required to repair it? 4:07(5 votes)
- Yes, aneurysm is a serious problem and require immediate medical attention.(5 votes)
- Can people get aneurysms in the veins and if so are they called something different? Are the aneurysms in the the small arteries just as life threatening as the ones in the large arteries over time? When a doctor does surgery on an aneurysm, does he just cut it out and stitch it up or does he need to graft on a piece of tissue? Is it possible to reverse or control Arteriosclerosis with or without lowering blood pressure?(4 votes)
- Arterial aneurysms is more common due to higher pressure, but venous aneurysms can occur.
Treatment is based on location and size. For example small aneurysms in the brain, can be "coiled", meaning the surgeon fill it with a thin thread, untill it is completely closed, and leave it with that. Bigger aneurisms in the abdomen is often cut open, and a graft made of for example gore-tex is placed inside the artery before it is closed again.
Blood pressure control (lowering blood pressure if high) will help against developing arteriosclerosis, amongst other things.(5 votes)
- an aneurysm in the brain for example should be very dangerous.
is it common?(2 votes)- Doing a quick Google search for "cerebral aneurysm incidence rates" showed that the most common estimate is approximately 30,000 ruptured brain aneurysms a year in the US, with somewhere around ~40% being fatal.(1 vote)
- what are the symptoms of hypertension?(1 vote)
- A headache is a common symptom that many people ignore, or try to treat themselves with tylenol or advil, but is actually a symptom of their hypertension.(2 votes)
- can you have hemorrhage from an artery that is arteriosclerotic? in the sense of an aneurism but i imagine it like a crack in a pipe?(1 vote)
- Yes, something called a dissection can cause the "crack" that you are thinking about and blood can track between parts of wall of the blood vessel. The other thing that can happen is an aneurysm. Otherwise, it's not common to have them just rupture and hemorrhage.(1 vote)
- Why does high blood pressure cause arterio(lo)sclerosis?(1 vote)
- Are the capillaries affected?(1 vote)
- Is arteriosclerosis and atherosclerosis the same thing? I thought arteriosclerosis was the buildup of plaque in the arteries..does the term include both plaque buildup and he hardening/stiffening of arteries?(1 vote)
- After hypertension becomes controlled by medication, are any of its effects reversible over time? (Not anerysms, but lesser damage such as wear of the vessel linings or stiffening of the arteries...)(1 vote)
- @, HOW do arteries eventually lose their elasticity and become firm? does the high blood pressure erode away muscle that makes it elastic? 2:33(1 vote)
Video transcript
Now, we've talked
about hypertension, and you know that it means that
you have high blood pressure. So the next logical thing to
think about is why is that bad? Why is it a problem to
have high blood pressure? And I like to think
about high blood pressure from two different
perspectives-- one would be the perspective of
the heart, and the other is the perspective
of the blood vessels. And so here you can
almost divide it up as the thing that's
making the pressure or generating the pressure,
which is the heart, and the thing that's
receiving the pressure. So generating versus receiving
pressure, and each of these two areas has some serious
consequences for the body. So let's just divide it up here. Let's just draw a dashed
line, divide up our screen, and we'll talk about both areas. So let's start with the
receiving pressure side. So we have the large and
middle sized arteries-- and specifically I mean
arteries that are between, let's say, 25 millimeters
in diameter all the way down to about one
millimeter in diameter. So primarily these
are the vessels that are going to get
blood from the heart to the different organs
that it needs to get to. And then you of course have the
small arteries and arterioles. And these are going
to be at the high end. They're going to
be one millimeter. But they're going to go
all the way down and get smaller and smaller to about
0.01 millimeters, so about 1/100 of the size. They're very tiny. And these are
receiving pressure. Both of them are
receiving pressure. These I'll draw as-- I'll
leave the drawing up above, and these are kind of very,
very narrow ones, right? So both of them are
receiving the pressure, and they're going
to have problems. So for example, if
you have, let's say, a large or middle
artery that is-- let me draw it in
a different color. Let's say here it's
very elastic-- over time if you keep exposing
this elastic vessel or tube to high pressures,
over time what would happen is this becomes very
firm, like a pipe. So that's one change. And in fact, that change
from being elastic to firm, we call that arteriosclerosis. I'll write that in
white-- arteriosclerosis. And in fact, a
very similar thing happens on the other side
with the small arteries and arterioles. They also have very
similar kind of change. They can go from being
very elastic-- I'm trying to draw it so it's
got some springiness. That's obviously kind
of tricky to draw. These become very firm
as well over time, and they lose that elasticity. And when it happens in the
small arteries or arterioles, we call that
arteriolosclerosis-- a very similar
word, but slightly different-- arteriolo-- an
extra L and an O-- sclerosis. So this is the
difference, right? They're very similar things,
kind of similar processes, but one is in the
smaller arteries and one is in the larger
and middle sized arteries. So this is one of
the things that can happen when you have
lots of high blood pressure constantly exposed
to the vessels. They can become firm. OK, going back to the
large and middle arteries, you also can have a
situation-- I'll draw it here-- where you have an artery,
let's say-- actually, let me write what it is first. You can have an aneurysm. And an aneurysm is where
you have a vessel-- let's say this is my vessel, and
it's taking blood through it. So blood is going through it. And because of the
constant blood pressure that's going
through this vessel, the wall starts to get weak. So at one spot, it
starts to get weak. Let's say right here
instead of being like that, it starts to look like this. And you get this little
area of weakness. I'll try to draw it like that. And because it's weak, the blood
will start going, and hitting, and bouncing off the walls, and
making it a little bit bigger. So it looks like that. And over time, it might do this. It might become a big sack. And that's an aneurysm. And actually that aneurysm,
if it's a sack of blood, can actually burst and break. And that blood can spill out,
and we call that hemorrhage. So you can actually
have an aneurysm because of a weak vessel wall. Now, looking at the small
arteries or arterioles, you can also have,
not necessarily aneurysms in the
same way, but you can have breaking or hemorrhage. And here I want to
show you or remind you that these vessels,
these tiny ones anyway, they're usually not sitting
out there on their own. They're usually within an organ. So this tiny vessel--
remember, it's one millimeter to a
hundredth of a millimeter. So it's actually sitting
inside of a kidney or sitting inside of an eye. And so these organs
have inside of them these arterioles
and small arteries. And so when they're in that
situation, if you have a break, let's say-- actually,
let me rewrite this slightly differently. If you have a break
in the vessel, we actually get organ damage. So this could be because
the vessel literally breaks right here
and blood spills out. And it could also be because
these tiny vessels are necessary to make
the organ work. For example, the kidneys require
that these small arteries and arterioles are
working properly. And if they're not, you
start getting some problems with being able to do
the job of the kidney. And so you can
get kidney damage. Or if it's in your eye, you can
get what we call retinopathy, basically meaning that the
retina is not working properly. So you can have kidney
damage or retinopathy. You can have aneurysms,
arteriosclerosis, or arteriolosclerosis. And these are all
related to the fact that the blood
vessels are breaking or they're becoming more firm. And this is all on the
side of receiving pressure.