[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:02.13,0:00:04.83,Default,,0000,0000,0000,,I really like this picture that I found. It actually
Dialogue: 0,0:00:04.83,0:00:08.46,Default,,0000,0000,0000,,shows you really neatly where the heart sits in our body
Dialogue: 0,0:00:08.46,0:00:12.54,Default,,0000,0000,0000,,so you can see the heart is surrounded, on both sides, by ribs, right?
Dialogue: 0,0:00:12.54,0:00:16.20,Default,,0000,0000,0000,,And in fact, I didn't draw it in yet, but let me show you where the
Dialogue: 0,0:00:16.20,0:00:20.08,Default,,0000,0000,0000,,lungs would be. This is the right lung
Dialogue: 0,0:00:20.08,0:00:23.46,Default,,0000,0000,0000,,and on this side you'd have the left lung. So this is where
Dialogue: 0,0:00:23.46,0:00:27.54,Default,,0000,0000,0000,,your heart sits: between two lungs. And I'm saying
Dialogue: 0,0:00:27.54,0:00:31.42,Default,,0000,0000,0000,,left and right from the perspective of the the person who owns this
Dialogue: 0,0:00:31.42,0:00:35.70,Default,,0000,0000,0000,,heart. So this is their left and right, which is the opposite
Dialogue: 0,0:00:35.70,0:00:39.33,Default,,0000,0000,0000,,of us if we're looking at it. The heart is actually sitting between the two
Dialogue: 0,0:00:39.33,0:00:42.95,Default,,0000,0000,0000,,lungs within this protective casing that
Dialogue: 0,0:00:42.95,0:00:47.07,Default,,0000,0000,0000,,the ribs are basically there to keep all these important organs
Dialogue: 0,0:00:47.07,0:00:51.11,Default,,0000,0000,0000,,safe. And then below them, so if you draw
Dialogue: 0,0:00:51.11,0:00:55.53,Default,,0000,0000,0000,,this here. Or if I draw it, you can
Dialogue: 0,0:00:55.53,0:00:58.61,Default,,0000,0000,0000,,see now that below all this stuff is
Dialogue: 0,0:00:58.61,0:01:02.86,Default,,0000,0000,0000,,a really really important muscle. So this muscle
Dialogue: 0,0:01:02.86,0:01:07.31,Default,,0000,0000,0000,,people don't talk about this muscle, or this is not the kind of muscle
Dialogue: 0,0:01:07.31,0:01:10.85,Default,,0000,0000,0000,,that you usually see people working on at the gym, but this muscle is called the diaphragm.
Dialogue: 0,0:01:10.85,0:01:15.11,Default,,0000,0000,0000,,So your diaphragm muscle
Dialogue: 0,0:01:15.11,0:01:22.84,Default,,0000,0000,0000,,and your ribs are enclosing a space, right? The diaphragm becomes the floor, and the ribs are kind of the
Dialogue: 0,0:01:22.84,0:01:25.69,Default,,0000,0000,0000,,ceiling and the walls of this space.
Dialogue: 0,0:01:25.69,0:01:30.19,Default,,0000,0000,0000,,And if you look at the contents of this space, you'd have your lung
Dialogue: 0,0:01:30.19,0:01:33.77,Default,,0000,0000,0000,,and you'd have your heart. So, this entire space then
Dialogue: 0,0:01:33.77,0:01:38.86,Default,,0000,0000,0000,,is called your thorax.
Dialogue: 0,0:01:38.86,0:01:42.27,Default,,0000,0000,0000,,So what exactly does the heart do? Let's actually make a little bit of
Dialogue: 0,0:01:42.27,0:01:45.84,Default,,0000,0000,0000,,space now, and bring up a
Dialogue: 0,0:01:45.84,0:01:47.77,Default,,0000,0000,0000,,zoomed in version of the heart.
Dialogue: 0,0:01:47.77,0:01:53.97,Default,,0000,0000,0000,,Let me start by orienting you to the heart. This is our right lung
Dialogue: 0,0:01:53.97,0:01:58.04,Default,,0000,0000,0000,,and on the other side we have our left lung. And all this would be
Dialogue: 0,0:01:58.04,0:02:01.38,Default,,0000,0000,0000,,inside of the rib cage, but I'm not going to draw that now, because that would
Dialogue: 0,0:02:01.38,0:02:05.50,Default,,0000,0000,0000,,make it harder to see the heart itself. So to think
Dialogue: 0,0:02:05.50,0:02:09.73,Default,,0000,0000,0000,,about exactly what the heart does, I think one, kind of neat way to do it is
Dialogue: 0,0:02:09.73,0:02:13.43,Default,,0000,0000,0000,,to actually imagine that you're a cell. So put yourself in the perspective
Dialogue: 0,0:02:13.43,0:02:17.36,Default,,0000,0000,0000,,of a cell, and let's say you're a cell hanging out
Dialogue: 0,0:02:17.36,0:02:21.20,Default,,0000,0000,0000,,over here. This is you. And you can
Dialogue: 0,0:02:21.20,0:02:25.01,Default,,0000,0000,0000,,think about any part of the body that you could be. Let's say a little
Dialogue: 0,0:02:25.01,0:02:27.98,Default,,0000,0000,0000,,toe cell. So let's say you're a toe cell
Dialogue: 0,0:02:27.98,0:02:32.74,Default,,0000,0000,0000,,and your job, of course, is to live and be happy,and you've got
Dialogue: 0,0:02:32.74,0:02:36.83,Default,,0000,0000,0000,,near by, a little blood vessel. And in fact, every cell in our body
Dialogue: 0,0:02:36.83,0:02:40.79,Default,,0000,0000,0000,,has a little blood vessel that's near by. And this toe cell
Dialogue: 0,0:02:40.79,0:02:44.21,Default,,0000,0000,0000,,is just trying to make a living. And toe
Dialogue: 0,0:02:44.21,0:02:48.91,Default,,0000,0000,0000,,cells need certain things, right? They need, for example, let's say oxygen.
Dialogue: 0,0:02:48.91,0:02:52.82,Default,,0000,0000,0000,,I'll write it in white so it's very clear. They need oxygen
Dialogue: 0,0:02:52.82,0:02:56.59,Default,,0000,0000,0000,,and they need nutrients, right?
Dialogue: 0,0:02:56.59,0:03:00.43,Default,,0000,0000,0000,,So cells need certain things to live and be happy.
Dialogue: 0,0:03:00.43,0:03:03.94,Default,,0000,0000,0000,,And on the flip-side, they also make waste. They're in
Dialogue: 0,0:03:03.94,0:03:08.27,Default,,0000,0000,0000,,a sense just like us, they make waste. And that waste could be
Dialogue: 0,0:03:08.27,0:03:12.52,Default,,0000,0000,0000,,all sorts of things, and one that kind of jumps to mind is
Dialogue: 0,0:03:12.52,0:03:15.20,Default,,0000,0000,0000,,carbon dioxide (CO2). So carbon dioxide is waste
Dialogue: 0,0:03:15.20,0:03:19.39,Default,,0000,0000,0000,,for this cell. So it's making some
Dialogue: 0,0:03:19.39,0:03:23.49,Default,,0000,0000,0000,,waste and for the moment let's imagine that there's no blood flow.
Dialogue: 0,0:03:23.49,0:03:26.04,Default,,0000,0000,0000,,So, even though there's a blood vessel near by,
Dialogue: 0,0:03:26.04,0:03:29.90,Default,,0000,0000,0000,,really, no flow is happening, so I'll just write "no flow".
Dialogue: 0,0:03:29.90,0:03:34.31,Default,,0000,0000,0000,,So as the little cell
Dialogue: 0,0:03:34.31,0:03:38.95,Default,,0000,0000,0000,,makes waste. That waste, let's draw a little ball right here,
Dialogue: 0,0:03:38.95,0:03:42.08,Default,,0000,0000,0000,,it's going to start accumulating, you're going to start collecting more and more of it
Dialogue: 0,0:03:42.08,0:03:45.46,Default,,0000,0000,0000,,since the blood is not really flowing. And it might kind of
Dialogue: 0,0:03:45.46,0:03:50.44,Default,,0000,0000,0000,,end up getting all the way around our toe cell. So our toe cell is getting
Dialogue: 0,0:03:50.44,0:03:54.10,Default,,0000,0000,0000,,swamped, literally getting kind of covered by its own waste.
Dialogue: 0,0:03:54.10,0:03:58.76,Default,,0000,0000,0000,,And on the flip-side, is it getting oxygen or nutrients? No.
Dialogue: 0,0:03:58.76,0:04:01.94,Default,,0000,0000,0000,,It's not getting either of these things. So, before very
Dialogue: 0,0:04:01.94,0:04:06.13,Default,,0000,0000,0000,,long, I would say within minutes, our toe cell
Dialogue: 0,0:04:06.13,0:04:09.64,Default,,0000,0000,0000,,is thinking, "Well this is not a very happy way to live!" this is
Dialogue: 0,0:04:09.64,0:04:13.24,Default,,0000,0000,0000,,actually really very sad, this is awful. And if this continues
Dialogue: 0,0:04:13.24,0:04:17.42,Default,,0000,0000,0000,,the toe cell would die. So, what a toe
Dialogue: 0,0:04:17.42,0:04:20.63,Default,,0000,0000,0000,,cell needs, and what every cell needs, and that could be a finger cell or a
Dialogue: 0,0:04:20.63,0:04:25.20,Default,,0000,0000,0000,,skin cell, or really any cell that's living, needs
Dialogue: 0,0:04:25.20,0:04:29.35,Default,,0000,0000,0000,,flow. Right? It needs this blood to be flowing nicely
Dialogue: 0,0:04:29.35,0:04:31.62,Default,,0000,0000,0000,,and smoothly. And if there is flow
Dialogue: 0,0:04:31.62,0:04:36.24,Default,,0000,0000,0000,,then you get a very different picture, right? If there's flow then all the sudden all the
Dialogue: 0,0:04:36.24,0:04:39.56,Default,,0000,0000,0000,,waste product is actually now lifted and taken away.
Dialogue: 0,0:04:39.56,0:04:43.18,Default,,0000,0000,0000,,It's flowing away, and it's a little bit like having
Dialogue: 0,0:04:43.18,0:04:48.29,Default,,0000,0000,0000,,someone come by and pick up the trash, then you don't have trash all over the house.
Dialogue: 0,0:04:48.29,0:04:51.29,Default,,0000,0000,0000,,So then you have nice flow, and
Dialogue: 0,0:04:51.29,0:04:56.14,Default,,0000,0000,0000,,in return, oxygen and nutrients are delivered. So this stuff
Dialogue: 0,0:04:56.14,0:04:59.61,Default,,0000,0000,0000,,gets delivered as well. So, all of the sudden the cell is going to be
Dialogue: 0,0:04:59.61,0:05:03.61,Default,,0000,0000,0000,,very, very happy, and is going to be living just fine.
Dialogue: 0,0:05:03.61,0:05:06.98,Default,,0000,0000,0000,,So, really if you want all of the cells in your body to be living just fine
Dialogue: 0,0:05:06.98,0:05:11.41,Default,,0000,0000,0000,,like this cell here, you really want good flow throughout the
Dialogue: 0,0:05:11.41,0:05:15.10,Default,,0000,0000,0000,,body. And so this is really point number one. Is that you really
Dialogue: 0,0:05:15.10,0:05:19.07,Default,,0000,0000,0000,,need, somehow, to have blood flow moving and pushing
Dialogue: 0,0:05:19.07,0:05:22.12,Default,,0000,0000,0000,,blood constantly through the body. So,
Dialogue: 0,0:05:22.12,0:05:27.74,Default,,0000,0000,0000,,to do this for billions and billions of cells you would need a pretty powerful
Dialogue: 0,0:05:27.74,0:05:31.03,Default,,0000,0000,0000,,pump, right? Something that's going to be able to pull
Dialogue: 0,0:05:31.03,0:05:35.28,Default,,0000,0000,0000,,in all the blood from the body, and then push it back out. And that's what the heart
Dialogue: 0,0:05:35.28,0:05:39.22,Default,,0000,0000,0000,,is. I mean at its core, that's exactly what the heart is doing.
Dialogue: 0,0:05:39.22,0:05:42.91,Default,,0000,0000,0000,,It's an amazing pump, pushing blood, so that
Dialogue: 0,0:05:42.91,0:05:45.54,Default,,0000,0000,0000,,you have good blood flow. And so I'm
Dialogue: 0,0:05:45.54,0:05:49.52,Default,,0000,0000,0000,,going to write that on the side as kind of job number one. These are the jobs of the heart.
Dialogue: 0,0:05:49.52,0:05:53.48,Default,,0000,0000,0000,,So jobs, and number one, would be
Dialogue: 0,0:05:53.48,0:05:56.04,Default,,0000,0000,0000,,blood flow. And I'll write systemic
Dialogue: 0,0:05:56.04,0:06:01.05,Default,,0000,0000,0000,,flow. Systemic flow. And all
Dialogue: 0,0:06:01.05,0:06:05.04,Default,,0000,0000,0000,,that systemic means is that I'm refering to the entire body. So systemic
Dialogue: 0,0:06:05.04,0:06:08.78,Default,,0000,0000,0000,,when I say that word, I just mean the entire body. All the cells
Dialogue: 0,0:06:08.78,0:06:12.86,Default,,0000,0000,0000,,in the body. Now, exactly how that happens actually
Dialogue: 0,0:06:12.86,0:06:16.51,Default,,0000,0000,0000,,you can see on this picture. So, here you have a giant
Dialogue: 0,0:06:16.51,0:06:20.66,Default,,0000,0000,0000,,vein, this is a vein, and you have an artery.
Dialogue: 0,0:06:20.66,0:06:23.60,Default,,0000,0000,0000,,This is an artery.
Dialogue: 0,0:06:23.60,0:06:28.70,Default,,0000,0000,0000,,And blood is actually going through the artery, that way.
Dialogue: 0,0:06:28.70,0:06:32.94,Default,,0000,0000,0000,,And it's actually coming into two veins, the one
Dialogue: 0,0:06:32.94,0:06:36.82,Default,,0000,0000,0000,,at the top, this is called the superior, superior just kind of means
Dialogue: 0,0:06:36.82,0:06:40.49,Default,,0000,0000,0000,,at the top. Superior vena cava. That's the
Dialogue: 0,0:06:40.49,0:06:44.38,Default,,0000,0000,0000,,name of the vein. And at the bottom here, you can't see it because
Dialogue: 0,0:06:44.38,0:06:48.50,Default,,0000,0000,0000,,it's on the other side of the heart, but there's another vein called the inferior vena cava.
Dialogue: 0,0:06:48.50,0:06:51.52,Default,,0000,0000,0000,,And these two veins, this is also a vein,
Dialogue: 0,0:06:51.52,0:06:57.53,Default,,0000,0000,0000,,these two veins are actually dragging blood in from all over the body,
Dialogue: 0,0:06:57.53,0:06:59.41,Default,,0000,0000,0000,,into the heart.
Dialogue: 0,0:06:59.41,0:07:02.91,Default,,0000,0000,0000,,And then, when the heart is ready to pump it back out, it goes into this
Dialogue: 0,0:07:02.91,0:07:07.26,Default,,0000,0000,0000,,artery, and the name of it is the aorta.
Dialogue: 0,0:07:07.26,0:07:10.83,Default,,0000,0000,0000,,So if you've heard of the aorta, this is the artery that people
Dialogue: 0,0:07:10.83,0:07:14.86,Default,,0000,0000,0000,,are talking about. So this is how blood comes and gets pumped
Dialogue: 0,0:07:14.86,0:07:18.78,Default,,0000,0000,0000,,around. But this isn't actually the only job of the heart. The job,
Dialogue: 0,0:07:18.78,0:07:22.46,Default,,0000,0000,0000,,the second job of the heart, is actually
Dialogue: 0,0:07:22.46,0:07:26.54,Default,,0000,0000,0000,,also in this picture, and it's called pulmonary flow.
Dialogue: 0,0:07:26.54,0:07:30.52,Default,,0000,0000,0000,,Pulmonary flow. So, what does that
Dialogue: 0,0:07:30.52,0:07:34.12,Default,,0000,0000,0000,,mean? Well, we know that cells are expecting
Dialogue: 0,0:07:34.12,0:07:39.08,Default,,0000,0000,0000,,oxygen, right? We know this. And that they have a lot of carbon dioxide
Dialogue: 0,0:07:39.08,0:07:42.32,Default,,0000,0000,0000,,waste. Well, it's good to move things around. It's good
Dialogue: 0,0:07:42.32,0:07:45.40,Default,,0000,0000,0000,,to move blood around. But if you actually never got rid of that carbon dioxide
Dialogue: 0,0:07:45.40,0:07:49.79,Default,,0000,0000,0000,,or brought in new oxygen, then a cell is not going to be very happy either.
Dialogue: 0,0:07:49.79,0:07:53.11,Default,,0000,0000,0000,,I mean, you can have blood flow, but at some point it's also going to want some oxygen.
Dialogue: 0,0:07:53.11,0:07:57.27,Default,,0000,0000,0000,,And it's going to want to get rid of that carbon dioxide. So, that's where the
Dialogue: 0,0:07:57.27,0:08:00.91,Default,,0000,0000,0000,,lungs come in. So what happens is that the heart, before
Dialogue: 0,0:08:00.91,0:08:05.44,Default,,0000,0000,0000,,sending blood out the aorta, before just dishing it out back into the body,
Dialogue: 0,0:08:05.44,0:08:09.41,Default,,0000,0000,0000,,it actually sends the blood over to the
Dialogue: 0,0:08:09.41,0:08:12.90,Default,,0000,0000,0000,,lungs. And it goes over to the left lung, and over to the right lung.
Dialogue: 0,0:08:12.90,0:08:17.19,Default,,0000,0000,0000,,And the blood comes back from the right lung
Dialogue: 0,0:08:17.19,0:08:21.28,Default,,0000,0000,0000,,and the left lung, and gets pushed back into
Dialogue: 0,0:08:21.28,0:08:24.63,Default,,0000,0000,0000,,the heart, and then gets squeezed through the aorta. So there's this
Dialogue: 0,0:08:24.63,0:08:28.22,Default,,0000,0000,0000,,actual extra little step here, where blood is going to
Dialogue: 0,0:08:28.22,0:08:32.53,Default,,0000,0000,0000,,and from the lungs, and that's the pulmonary flow.
Dialogue: 0,0:08:32.53,0:08:36.81,Default,,0000,0000,0000,,So the final thing you'll notice, if you look at this picture it's hard not to notice,
Dialogue: 0,0:08:36.81,0:08:40.20,Default,,0000,0000,0000,,is that there are these, kind of wriggly looking little
Dialogue: 0,0:08:40.20,0:08:44.34,Default,,0000,0000,0000,,blood vessels all over the heart. And what are these
Dialogue: 0,0:08:44.34,0:08:47.03,Default,,0000,0000,0000,,exactly? I mean, you've got red ones, and blue ones, and
Dialogue: 0,0:08:47.03,0:08:50.36,Default,,0000,0000,0000,,the blue ones are the veins, and the red ones are the arteries
Dialogue: 0,0:08:50.36,0:08:55.27,Default,,0000,0000,0000,,but are they part of the systemic flow, or pulmonary flow, or something else?
Dialogue: 0,0:08:55.27,0:08:58.48,Default,,0000,0000,0000,,Well, these vessels, all of them,
Dialogue: 0,0:08:58.48,0:09:01.94,Default,,0000,0000,0000,,together are called coronary vessels.
Dialogue: 0,0:09:01.94,0:09:06.93,Default,,0000,0000,0000,,And so specifically you might hear about
Dialogue: 0,0:09:06.93,0:09:10.72,Default,,0000,0000,0000,,a coronary artery, or a coronary vein, but together you can call them
Dialogue: 0,0:09:10.72,0:09:14.45,Default,,0000,0000,0000,,coronary blood vessels. I'll add the word blood here. So these
Dialogue: 0,0:09:14.45,0:09:18.11,Default,,0000,0000,0000,,coronary blood vessels are actually serving the heart muscle
Dialogue: 0,0:09:18.11,0:09:20.72,Default,,0000,0000,0000,,itself. I mean remember, the heart
Dialogue: 0,0:09:20.72,0:09:24.72,Default,,0000,0000,0000,,is made up of thousands and thousands, actually tens of thousands of cells
Dialogue: 0,0:09:24.72,0:09:29.95,Default,,0000,0000,0000,,and those cells, just like our toe cell that we drew,
Dialogue: 0,0:09:29.95,0:09:33.64,Default,,0000,0000,0000,,they also need oxygen, nutrients, and have waste.
Dialogue: 0,0:09:33.64,0:09:37.22,Default,,0000,0000,0000,,So, those cells are going to need blood vessels supplying
Dialogue: 0,0:09:37.22,0:09:40.32,Default,,0000,0000,0000,,them as well. So, that's what the coronary blood vessels are. They're literally
Dialogue: 0,0:09:40.32,0:09:43.84,Default,,0000,0000,0000,,the blood vessels that go to and serve
Dialogue: 0,0:09:43.84,0:09:47.74,Default,,0000,0000,0000,,the heart. So these are the ones that serve the heart.
Dialogue: 0,0:09:47.74,0:09:51.06,Default,,0000,0000,0000,,Now, if they're serving the heart muscles
Dialogue: 0,0:09:51.06,0:09:55.62,Default,,0000,0000,0000,,and the heart cells, then, think about it, would they fit under
Dialogue: 0,0:09:55.62,0:09:59.30,Default,,0000,0000,0000,,the systemic flow, or pulmonary flow? Well if the
Dialogue: 0,0:09:59.30,0:10:03.41,Default,,0000,0000,0000,,main job is to serve the needs of cells, then
Dialogue: 0,0:10:03.41,0:10:08.17,Default,,0000,0000,0000,,the coronary vessels fall under the systemic flow.