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Course: Health and medicine > Unit 3
Lesson 2: Atherosclerosis, arteriosclerosis, and arteriolosclerosisArteriosclerosis, arteriolosclerosis, and atherosclerosis
Learn the difference between Arteriosclerosis, Arteriolosclerosis, and Atherosclerosis! Rishi is a pediatric infectious disease physician and works at Khan Academy. Created by Rishi Desai.
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- so the fibrous tissue is the main cause of the non-compliance of the arteries in atheroscelerosis? or do the calcium ions also contribute to the hardening?(4 votes)
- Both things contribute to atherosclerosis, but the fibrous tissue contributes more than the calcium ions do.(2 votes)
- If you got one of those diseases,which would be very fatal and kill you?(1 vote)
- None of these diseases are terribly lethal on their own. They can create complications and worsen cardiac conditions, but they aren't super lethal in the same manner of, say, pancreatic cancer.(7 votes)
- How exactly does diabetes cause arteriolosclerosis?(1 vote)
- It is very complex and the biochemical pathways are not completely understood. But essentially chronic hyperglycaemia (high blood sugar for a long time) caused by poorly managed diabetes leads to endothelial damage via the production of reactive oxygen species. Because the stimulus is not removed this becomes chronic inflammation. Continued injury to the cells and repeated attempts to repair the damage via proliferation of smooth muscle result.(4 votes)
- Why is it more likely to occur due to plaque build up in large/middle sized arteries?(1 vote)
- larger arteries have more room for build up but in the smaller arteries diffusion happens so quick it's hard for the plac to build up.(3 votes)
- When the artery loses compliance, what happens? is it a good thing? I realise it is the cause of something bad, but does it happen to prevent worse from happening? eg. Arteries close or get blocked?(1 vote)
- When vessels lose compliance it a very bad thing. It's basically another way of saying they're getting stiff and can't adapt as well to the different way blood may flow through them. This can cause higher blood pressures, damage the vessels walls, lead to hypoxia, etc. lots of bad things and not really anything good that comes out of it! But, unfortunately it's something that happens to everyone as they age and their body wears and tears. Especially people with atherosclerosis are prone to this (as explained in the video) because the plaques are what cause the stiffening and damage(3 votes)
- Can you totally lose compliance?(1 vote)
- Yes. This increases the likelihood of rupture and plaque emboli breaking off and causing stroke. The atherosclerotic lesions will eventually be remodeled with calcium, leaving behind a hard outer casing, which looks and feels like bone.(3 votes)
- is there a way to avoid this?(2 votes)
- so arteriosclerosis increases the blood pressure reading?(1 vote)
- arteriosclerosis prevent artries from diltation if there is alot of blood injected by heart so the artery is narrow what makes high blood pressure(2 votes)
- At, you mentioned that there is high blood pressure in the lumen and there are some proteins that are pushed out into the walls of the arterioles. I don't get it because it goes against one of the pressure laws. Aren't the pressure pushing supposed to go down when the blood pressure is high? And vice versa? 8:09(1 vote)
- Factually; atherosclerosis refers to fat building up in the wall of the artery, not in the area of blood-flow as you portray. The calcification/stiffening is also in the cell wall. Why do you propogate the idea that arteries clog up?(1 vote)
- Myocardial infarctions (heart attacks) happen with a buildup of atherosclerotic plaque blocking blood flow to a region of the heart supplied by the blocked vessel.(1 vote)
Video transcript
So there are a few words
that get thrown around, and when I was going
through and learning them, I was always confused. And so I thought I'd go and
talk about them right now. The first word is
arteriosclerosis. And I'm going to underline
the one "o" here. And very similar to
this word, there's the word arteriolosclerosis,
with an extra "l" and "o", and everything else is the same. The first thing
I always wondered was, are these the same word
that someone just misspelled? But actually that's
not the case. This is two separate words
for two separate things. And the third word
is atherosclerosis. I always used to wonder the
same thing about this word. It was just like, is this
just another way to spell it? Maybe the British spelling
or something like that? But actually it's
another word that's different in meaning as well. So these three words often
get confused for one another. And sometimes you'll
even see that they are referred to
as the same thing. But there are some
subtle differences that I want to talk about. So let's start with
the first two words arterio- and arteriolosclerosis. And these basically
get to the question, answering the question, of What? What is happening? And the process of
arteriosclerosis and arteriolosclerosis
is that you basically have stiffening
of blood vessels. So if you have, let's
say, a normal vessel-- I'll draw it in red--
like a little rubber hose, this is a very soft,
flexible vessel. And over time, if it becomes
stiff, like a lead pipe, then you have something like
this, a very firm vessel. So the same size, but
basically the walls are becoming very, very stiff. And arteriolosclerosis is
kind of the same process. And so, so far I have
not convinced you that there's any
difference, right? Same basic process. So you're probably left
wondering, well, then what is the difference? I'm going to firm. Well, the difference is
that arteriosclerosis is happening in
the large arteries and middle sized arteries. And remember we divided up the
arteries into large and middle. And on the other side, we said,
what about the small arteries and arterials? And that's over here. So basically, if this
process is happening in the large or
middle arteries, we would call it arteriosclerosis
with a single "o." But if it's happening in the
small arteries and arterials, we would call the same
process arteriolosclerosis. So that's the key
difference, right? Where is it happening? Now in terms of answering
the question of what, this is the process. But you have to ask yourself,
why does that matter? Why does it matter
if something's going from soft to firm? Now, I'm going to draw a
little spectrum for you, and on this side, we
have the word "not," and here you have "very." And these are referring
to compliance. So try to remember back to
what we said about compliance. And that's whether or not a
vessel can stretch, almost like stretchability. And if you think
about what would be very stretchable, or very
compliant, we've got veins. So that would be
over here, a vein. Very compliant, right? And arteries are over here. They're not so compliant. They're not completely
stiff, but compared to veins, they're not very compliant. So they have a much lower
compliance than veins. And a lead pipe would be
right here, basically right next to "not." This would be a
lead pipe, right? And so when we talk
about arteriosclerosis or arteriolosclerosis
as something that's soft going into
something that's firm, we're really talking
about the artery moving from where it is on the
compliance spectrum over here, towards not too
compliant at all. So really we're talking
about losing compliance. Let me write that--
losing compliance. That's really important. And that's really what
we're talking about. Losing compliance. Now, how do we get to a point
where we're losing compliance? How does that happen, exactly? Well, that's another question. That's the question of
how, how does this happen? And there we can talk
about atherosclerosis. So atherosclerosis is a
process, and that-- I can even draw it out for
you very quickly. This is, let's say, a
blood vessel, an artery. And I'll draw two
layers for its wall, although we know that there's
actually three layers. Just to make it simple. I'm just drawing two
layers just to show you there's a thickness. And let's say that you
have some fat deposit here, and maybe one over here. And over time, we
know that this is going to cause some
blockage of the vessel. But also, in addition
to losing space in the lumen--
this is the lumen-- in addition to losing
space in the lumen, you also have some
calcification, and some fibrous tissue starts
kind of laying down here. So this wall, instead of
being nice and soft and red, I'm going to draw it
as very firm and white. Very firm. So this part of
the wall, and maybe even this part of the wall,
become very non-compliant. They lose compliance here. So these parts of the
walls are very firm. They're not going to
stretch out very easily. So that's atherosclerosis. And the reason I listed
it under this section-- here, if I can
divide it in half-- is that most often, not always,
but most often, atherosclerosis is happening in the larger
or middle sized arteries. It doesn't happen as often
in the small arteries and arterials. So it's happening more often in
the large and middle arteries, and so it's going to
cause arteriosclerosis. So atherosclerosis is the
"how," and arteriosclerosis is the "what" for the large
and middle sized arteries. Now let's shift over to the
small arteries and arterials. So, if I just told you that
atherosclerosis doesn't happen too often in the small arteries,
well then, how in the world does arteriolosclerosis happen? Again, arteriolo, with an "olo." How does that happen? OK. Let me write out for
you a couple words. These are words
that you might come across-- hyaline
and hyperplastic. So, these are just
names for a process. So these are, again, these are
answering the question of "how" does arteriolosclerosis happen? Well, it happens through
hyaline or hyperplastic arteriolosclerosis, so the
word appears again here. And this-- let me just draw
it for you like I did before. We have a vessel. Instead of having a plaque,
which is what I drew before, in my vessel, this
time I'm going to talk about blood
pressure being really high. So here we're
talking about things like, let me write over
here, high blood pressure or, I'd say, diabetes. So in situations
like this, you can have lots and lots of pressure
pushing out of the vessel. This is my little arrows
talking about blood pressure. And as the pressure
is pushing out, what happens is that some
of the proteins from inside of the vessel-- let's say you
have some protein in here-- get pushed out. They're pushed out
into the vessel walls. And that vessel wall gets
loaded with protein, now, extra protein that doesn't
usually belong there. And it's got little
protein everywhere, because it's being pushed out
by all that high pressure. And over time, having all
this protein here-- I'm drawing in pink--
is going to cause these vessels to start
losing compliance. So all the way around, actually. They start losing compliance. And again, this is not
how it always happens, but this is just an example
of how it could happen. You could lose
compliance this way. So this would be an example
of how something that was soft is becoming very firm over
time because of blood pressure related issues. All right, we'll pick
up there next time.