[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:02.05,0:00:05.37,Default,,0000,0000,0000,,So what you're looking at is\None of the most amazing organs
Dialogue: 0,0:00:05.37,0:00:06.11,Default,,0000,0000,0000,,in your body.
Dialogue: 0,0:00:06.11,0:00:07.60,Default,,0000,0000,0000,,This is the human heart.
Dialogue: 0,0:00:07.60,0:00:10.92,Default,,0000,0000,0000,,And it's shown with\Nall the vessels on it.
Dialogue: 0,0:00:10.92,0:00:14.05,Default,,0000,0000,0000,,And you can see the vessels\Ncoming into it and out of it.
Dialogue: 0,0:00:14.05,0:00:16.04,Default,,0000,0000,0000,,But the heart, at\Nits core, is a pump.
Dialogue: 0,0:00:16.04,0:00:20.25,Default,,0000,0000,0000,,And this pump is why we call\Nit the hardest working organ
Dialogue: 0,0:00:20.25,0:00:20.75,Default,,0000,0000,0000,,in our body.
Dialogue: 0,0:00:20.75,0:00:24.25,Default,,0000,0000,0000,,Because it starts pumping blood\Nfrom the point where you're
Dialogue: 0,0:00:24.25,0:00:26.80,Default,,0000,0000,0000,,a little fetus, maybe\Nabout eight weeks old,
Dialogue: 0,0:00:26.80,0:00:29.44,Default,,0000,0000,0000,,all the way until the\Npoint where you die.
Dialogue: 0,0:00:29.44,0:00:31.79,Default,,0000,0000,0000,,And so this organ,\NI think, would
Dialogue: 0,0:00:31.79,0:00:34.22,Default,,0000,0000,0000,,be really cool to look at\Nin a little bit more detail.
Dialogue: 0,0:00:34.22,0:00:36.43,Default,,0000,0000,0000,,But it's hard to do that\Nlooking just at the outside.
Dialogue: 0,0:00:36.43,0:00:39.26,Default,,0000,0000,0000,,So what I did is I\Nactually drew what
Dialogue: 0,0:00:39.26,0:00:40.63,Default,,0000,0000,0000,,it might look like\Non the inside.
Dialogue: 0,0:00:40.63,0:00:43.28,Default,,0000,0000,0000,,So let me actually\Njust show you that now.
Dialogue: 0,0:00:43.28,0:00:45.76,Default,,0000,0000,0000,,And we'll follow\Nthe path of blood
Dialogue: 0,0:00:45.76,0:00:48.63,Default,,0000,0000,0000,,through the heart\Nusing this diagram.
Dialogue: 0,0:00:48.63,0:00:51.73,Default,,0000,0000,0000,,Let me start with a little\Npicture in the corner.
Dialogue: 0,0:00:51.73,0:00:55.02,Default,,0000,0000,0000,,So let's say we\Nhave a person here.
Dialogue: 0,0:00:55.02,0:00:57.54,Default,,0000,0000,0000,,And this is their face,\Nand this is their neck.
Dialogue: 0,0:00:57.54,0:01:00.73,Default,,0000,0000,0000,,I'm going to draw their arms.
Dialogue: 0,0:01:00.73,0:01:05.32,Default,,0000,0000,0000,,And they have, in the middle\Nof their chest, their heart.
Dialogue: 0,0:01:05.32,0:01:06.86,Default,,0000,0000,0000,,And so the whole\Ngoal is to make sure
Dialogue: 0,0:01:06.86,0:01:08.87,Default,,0000,0000,0000,,that blood from all\Nparts of their body,
Dialogue: 0,0:01:08.87,0:01:11.58,Default,,0000,0000,0000,,including their legs,\Ncan make its way back
Dialogue: 0,0:01:11.58,0:01:13.40,Default,,0000,0000,0000,,to the heart, first\Nof all, and then
Dialogue: 0,0:01:13.40,0:01:15.76,Default,,0000,0000,0000,,get pumped back out to the body.
Dialogue: 0,0:01:15.76,0:01:18.55,Default,,0000,0000,0000,,So blood is going to come\Nup from this arm, let's say,
Dialogue: 0,0:01:18.55,0:01:20.16,Default,,0000,0000,0000,,and dump into there.
Dialogue: 0,0:01:20.16,0:01:21.87,Default,,0000,0000,0000,,And the same on this side.
Dialogue: 0,0:01:21.87,0:01:23.51,Default,,0000,0000,0000,,And it's going to\Ncome from their head.
Dialogue: 0,0:01:23.51,0:01:26.51,Default,,0000,0000,0000,,And all three sources,\Nthe two arms and the head,
Dialogue: 0,0:01:26.51,0:01:30.28,Default,,0000,0000,0000,,are going to come together\Ninto one big vein.
Dialogue: 0,0:01:30.28,0:01:34.49,Default,,0000,0000,0000,,And that's going to be dumping\Ninto the top of the heart.
Dialogue: 0,0:01:34.49,0:01:36.19,Default,,0000,0000,0000,,And then separately,\Nyou've got veins
Dialogue: 0,0:01:36.19,0:01:39.42,Default,,0000,0000,0000,,from the legs meeting up\Nwith veins from the belly,
Dialogue: 0,0:01:39.42,0:01:42.35,Default,,0000,0000,0000,,coming into another\Nopening into the heart.
Dialogue: 0,0:01:42.35,0:01:44.50,Default,,0000,0000,0000,,So that's how the blood\Ngets back to the heart.
Dialogue: 0,0:01:44.50,0:01:48.17,Default,,0000,0000,0000,,And any time I\Nmention the word vein,
Dialogue: 0,0:01:48.17,0:01:49.77,Default,,0000,0000,0000,,I just want you to\Nmake sure you think
Dialogue: 0,0:01:49.77,0:01:52.05,Default,,0000,0000,0000,,of blood going\Ntowards the heart.
Dialogue: 0,0:01:55.16,0:01:57.16,Default,,0000,0000,0000,,Now if blood is going\Ntowards the heart,
Dialogue: 0,0:01:57.16,0:02:00.51,Default,,0000,0000,0000,,then after the blood\Nis pumped by the heart,
Dialogue: 0,0:02:00.51,0:02:02.55,Default,,0000,0000,0000,,it's going to have to\Ngo out to the heart.
Dialogue: 0,0:02:02.55,0:02:04.86,Default,,0000,0000,0000,,It's going to have to\Ngo away from the heart.
Dialogue: 0,0:02:04.86,0:02:06.12,Default,,0000,0000,0000,,So that's the aorta.
Dialogue: 0,0:02:06.12,0:02:08.44,Default,,0000,0000,0000,,And the aorta actually has\Na little arch, like that.
Dialogue: 0,0:02:08.44,0:02:10.46,Default,,0000,0000,0000,,We call it the aortic arch.
Dialogue: 0,0:02:10.46,0:02:14.86,Default,,0000,0000,0000,,And it sends off one vessel\Nto the arm, one vessel up
Dialogue: 0,0:02:14.86,0:02:17.69,Default,,0000,0000,0000,,this way, a vessel\Nover this way.
Dialogue: 0,0:02:17.69,0:02:20.10,Default,,0000,0000,0000,,And then this arch kind\Nof goes down, down, down
Dialogue: 0,0:02:20.10,0:02:22.92,Default,,0000,0000,0000,,and splits like that.
Dialogue: 0,0:02:22.92,0:02:24.84,Default,,0000,0000,0000,,So this is kind of a\Nsimplified version of it.
Dialogue: 0,0:02:24.84,0:02:26.52,Default,,0000,0000,0000,,But you can see how\Nthere are definitely
Dialogue: 0,0:02:26.52,0:02:29.25,Default,,0000,0000,0000,,some parallels between how\Nthe veins and the arteries
Dialogue: 0,0:02:29.25,0:02:30.57,Default,,0000,0000,0000,,are set up.
Dialogue: 0,0:02:30.57,0:02:34.44,Default,,0000,0000,0000,,And arteries, anytime I\Nmention the word artery,
Dialogue: 0,0:02:34.44,0:02:37.69,Default,,0000,0000,0000,,I want you to think of blood\Ngoing away from the heart.
Dialogue: 0,0:02:37.69,0:02:39.15,Default,,0000,0000,0000,,And an easy way to\Nremember that is
Dialogue: 0,0:02:39.15,0:02:41.69,Default,,0000,0000,0000,,that they both start\Nwith the letter A.
Dialogue: 0,0:02:41.69,0:02:43.84,Default,,0000,0000,0000,,So going to our big diagram now.
Dialogue: 0,0:02:43.84,0:02:47.90,Default,,0000,0000,0000,,We can see that blood coming\Nin this way and blood coming
Dialogue: 0,0:02:47.90,0:02:50.26,Default,,0000,0000,0000,,in this way is ending\Nup at the same spot.
Dialogue: 0,0:02:50.26,0:02:52.40,Default,,0000,0000,0000,,It's going to end up\Nat the-- actually,
Dialogue: 0,0:02:52.40,0:02:55.57,Default,,0000,0000,0000,,maybe I'll draw it here-- is\Nending up at the right atrium.
Dialogue: 0,0:02:58.42,0:03:00.94,Default,,0000,0000,0000,,That's just the\Nname of the chamber
Dialogue: 0,0:03:00.94,0:03:02.61,Default,,0000,0000,0000,,that the blood ends up in.
Dialogue: 0,0:03:02.61,0:03:06.96,Default,,0000,0000,0000,,And it came into the right\Natrium from a giant vessel
Dialogue: 0,0:03:06.96,0:03:10.04,Default,,0000,0000,0000,,up top called the\Nsuperior vena cava.
Dialogue: 0,0:03:10.04,0:03:12.71,Default,,0000,0000,0000,,And this is a vein, of\Ncourse, because it's
Dialogue: 0,0:03:12.71,0:03:15.17,Default,,0000,0000,0000,,bringing blood\Ntowards the heart.
Dialogue: 0,0:03:15.17,0:03:17.52,Default,,0000,0000,0000,,And down here, the\Ninferior vena cava.
Dialogue: 0,0:03:21.60,0:03:23.35,Default,,0000,0000,0000,,So these are the two\Ndirections that blood
Dialogue: 0,0:03:23.35,0:03:25.22,Default,,0000,0000,0000,,is going to be flowing.
Dialogue: 0,0:03:25.22,0:03:26.87,Default,,0000,0000,0000,,And once blood is\Nin the right atrium,
Dialogue: 0,0:03:26.87,0:03:29.63,Default,,0000,0000,0000,,it's going to head down\Ninto the right ventricle.
Dialogue: 0,0:03:29.63,0:03:33.72,Default,,0000,0000,0000,,So this is the right\Nventricle, down here.
Dialogue: 0,0:03:33.72,0:03:37.94,Default,,0000,0000,0000,,This is the second\Nchamber of the heart.
Dialogue: 0,0:03:37.94,0:03:40.44,Default,,0000,0000,0000,,And it gets there by\Npassing through a valve.
Dialogue: 0,0:03:40.44,0:03:43.32,Default,,0000,0000,0000,,And this valve, and all\Nvalves in the heart,
Dialogue: 0,0:03:43.32,0:03:44.80,Default,,0000,0000,0000,,are basically\Nthere to keep blood
Dialogue: 0,0:03:44.80,0:03:46.55,Default,,0000,0000,0000,,moving in the right direction.
Dialogue: 0,0:03:46.55,0:03:49.02,Default,,0000,0000,0000,,So it doesn't go in the\Nbackwards direction.
Dialogue: 0,0:03:49.02,0:03:51.26,Default,,0000,0000,0000,,So this valve is called\Nthe tricuspid valve.
Dialogue: 0,0:03:54.81,0:03:56.84,Default,,0000,0000,0000,,And it's called that\Nbecause it's basically
Dialogue: 0,0:03:56.84,0:03:58.16,Default,,0000,0000,0000,,got three little flaps.
Dialogue: 0,0:03:58.16,0:03:59.59,Default,,0000,0000,0000,,That's why they call it tri.
Dialogue: 0,0:03:59.59,0:04:01.61,Default,,0000,0000,0000,,And I know you can only\Nsee two in my drawing,
Dialogue: 0,0:04:01.61,0:04:04.81,Default,,0000,0000,0000,,and that's just because\Nmy drawing is not perfect.
Dialogue: 0,0:04:04.81,0:04:07.78,Default,,0000,0000,0000,,And it's hard to show a\Nflap coming out at you,
Dialogue: 0,0:04:07.78,0:04:09.66,Default,,0000,0000,0000,,but you can imagine it.
Dialogue: 0,0:04:09.66,0:04:11.95,Default,,0000,0000,0000,,So blood goes into\Nthe right ventricle.
Dialogue: 0,0:04:11.95,0:04:13.08,Default,,0000,0000,0000,,And where does it go next?
Dialogue: 0,0:04:13.08,0:04:15.20,Default,,0000,0000,0000,,Well after that, it's\Ngoing to go this way.
Dialogue: 0,0:04:15.20,0:04:17.53,Default,,0000,0000,0000,,It's going to go\Ninto this vessel,
Dialogue: 0,0:04:17.53,0:04:19.35,Default,,0000,0000,0000,,and it's going to split.
Dialogue: 0,0:04:19.35,0:04:22.29,Default,,0000,0000,0000,,But before it goes there, it has\Nto pass through another valve.
Dialogue: 0,0:04:22.29,0:04:26.65,Default,,0000,0000,0000,,So this is a valve, right here,\Ncalled the pulmonary valve.
Dialogue: 0,0:04:26.65,0:04:28.11,Default,,0000,0000,0000,,And it gives you\Na clue as to where
Dialogue: 0,0:04:28.11,0:04:29.08,Default,,0000,0000,0000,,things are going to go next.
Dialogue: 0,0:04:29.08,0:04:29.58,Default,,0000,0000,0000,,Right?
Dialogue: 0,0:04:29.58,0:04:33.03,Default,,0000,0000,0000,,Because the word\Npulmonary means lungs.
Dialogue: 0,0:04:33.03,0:04:36.18,Default,,0000,0000,0000,,And so, if this is my\Nlung, on this side,
Dialogue: 0,0:04:36.18,0:04:37.88,Default,,0000,0000,0000,,this is my left lung.
Dialogue: 0,0:04:37.88,0:04:43.15,Default,,0000,0000,0000,,And this is my right\Nlung, on this side.
Dialogue: 0,0:04:43.15,0:04:44.53,Default,,0000,0000,0000,,Then these vessels--\Nand I'll let
Dialogue: 0,0:04:44.53,0:04:48.01,Default,,0000,0000,0000,,you try to guess what they\Nwould be called-- these vessels.
Dialogue: 0,0:04:48.01,0:04:50.77,Default,,0000,0000,0000,,This would be my-- I want\Nto make sure I get my right
Dialogue: 0,0:04:50.77,0:04:52.00,Default,,0000,0000,0000,,and left straight.
Dialogue: 0,0:04:52.00,0:04:59.89,Default,,0000,0000,0000,,This is my left\Npulmonary artery.
Dialogue: 0,0:04:59.89,0:05:01.33,Default,,0000,0000,0000,,And I hesitated\Nthere just to make
Dialogue: 0,0:05:01.33,0:05:04.28,Default,,0000,0000,0000,,sure you got that because\Nit's taking blood away
Dialogue: 0,0:05:04.28,0:05:05.61,Default,,0000,0000,0000,,from the heart.
Dialogue: 0,0:05:05.61,0:05:11.37,Default,,0000,0000,0000,,And this is my right\Npulmonary artery.
Dialogue: 0,0:05:11.37,0:05:14.42,Default,,0000,0000,0000,,So this is my right and\Nleft pulmonary artery.
Dialogue: 0,0:05:14.42,0:05:16.30,Default,,0000,0000,0000,,And so blood goes,\Nnow, into my lungs.
Dialogue: 0,0:05:16.30,0:05:18.13,Default,,0000,0000,0000,,These are the lungs\Nthat are kind of nestled
Dialogue: 0,0:05:18.13,0:05:20.97,Default,,0000,0000,0000,,into my thorax, where\Nmy heart is sitting.
Dialogue: 0,0:05:20.97,0:05:22.80,Default,,0000,0000,0000,,It goes into my lungs.
Dialogue: 0,0:05:22.80,0:05:25.65,Default,,0000,0000,0000,,And remember, this\Nblood is blue.
Dialogue: 0,0:05:25.65,0:05:26.89,Default,,0000,0000,0000,,Why is it blue?
Dialogue: 0,0:05:26.89,0:05:30.11,Default,,0000,0000,0000,,Well, it's blue because it\Ndoesn't have very much oxygen.
Dialogue: 0,0:05:30.11,0:05:33.97,Default,,0000,0000,0000,,And so one thing that I\Nneed to pick up is oxygen.
Dialogue: 0,0:05:33.97,0:05:36.26,Default,,0000,0000,0000,,And so that's one\Nthing that the lungs
Dialogue: 0,0:05:36.26,0:05:38.08,Default,,0000,0000,0000,,are going to help me pick up.
Dialogue: 0,0:05:38.08,0:05:41.27,Default,,0000,0000,0000,,And I'm going to\Nwrite O2 for oxygen.
Dialogue: 0,0:05:41.27,0:05:42.73,Default,,0000,0000,0000,,And it's also blue.
Dialogue: 0,0:05:42.73,0:05:45.83,Default,,0000,0000,0000,,And that reminds us that\Nit's full of carbon dioxide.
Dialogue: 0,0:05:45.83,0:05:48.71,Default,,0000,0000,0000,,It's full of waste because\Nit's coming from the body.
Dialogue: 0,0:05:48.71,0:05:50.50,Default,,0000,0000,0000,,And the body's made a\Nlot of carbon dioxide
Dialogue: 0,0:05:50.50,0:05:52.33,Default,,0000,0000,0000,,that it's trying to get rid of.
Dialogue: 0,0:05:52.33,0:05:54.46,Default,,0000,0000,0000,,So in the lungs, you get\Nrid of your carbon dioxide
Dialogue: 0,0:05:54.46,0:05:56.80,Default,,0000,0000,0000,,and you pick up oxygen.
Dialogue: 0,0:05:56.80,0:05:59.02,Default,,0000,0000,0000,,So that's why I\Nswitch, at this point,
Dialogue: 0,0:05:59.02,0:06:03.18,Default,,0000,0000,0000,,from a blue-colored vessel\Nto a red-colored vessel.
Dialogue: 0,0:06:03.18,0:06:06.92,Default,,0000,0000,0000,,So now blood comes back in\Nthis way and this way and dumps
Dialogue: 0,0:06:06.92,0:06:08.70,Default,,0000,0000,0000,,into this chamber.
Dialogue: 0,0:06:08.70,0:06:09.43,Default,,0000,0000,0000,,So what is that?
Dialogue: 0,0:06:09.43,0:06:11.58,Default,,0000,0000,0000,,This is our left atrium.
Dialogue: 0,0:06:14.99,0:06:18.04,Default,,0000,0000,0000,,So just like our right atrium,\Nwe have one on the left.
Dialogue: 0,0:06:18.04,0:06:21.34,Default,,0000,0000,0000,,And it goes down into--\Nand you can probably
Dialogue: 0,0:06:21.34,0:06:25.23,Default,,0000,0000,0000,,guess what this one is called--\Nit's our left ventricle.
Dialogue: 0,0:06:25.23,0:06:28.82,Default,,0000,0000,0000,,So just like before, where\Nit went from the right atrium
Dialogue: 0,0:06:28.82,0:06:30.19,Default,,0000,0000,0000,,to the right\Nventricle, now we're
Dialogue: 0,0:06:30.19,0:06:33.73,Default,,0000,0000,0000,,going from the left atrium\Nto the left ventricle.
Dialogue: 0,0:06:33.73,0:06:35.71,Default,,0000,0000,0000,,And it passes\Nthrough a valve here.
Dialogue: 0,0:06:35.71,0:06:41.98,Default,,0000,0000,0000,,So this valve is called\Nthe mitral valve.
Dialogue: 0,0:06:41.98,0:06:43.83,Default,,0000,0000,0000,,And its job is, of\Ncourse, to make sure
Dialogue: 0,0:06:43.83,0:06:46.94,Default,,0000,0000,0000,,that blood does not go from\Nthe left ventricle back
Dialogue: 0,0:06:46.94,0:06:48.46,Default,,0000,0000,0000,,to the left atrium by accident.
Dialogue: 0,0:06:48.46,0:06:52.57,Default,,0000,0000,0000,,It wants to make sure\Nthat there's forward flow.
Dialogue: 0,0:06:52.57,0:06:54.83,Default,,0000,0000,0000,,And then the final\Nvalve-- I have
Dialogue: 0,0:06:54.83,0:06:58.45,Default,,0000,0000,0000,,to find a nice spot to\Nwrite it, maybe right here.
Dialogue: 0,0:06:58.45,0:07:01.00,Default,,0000,0000,0000,,This final valve that\Nit passes through
Dialogue: 0,0:07:01.00,0:07:02.24,Default,,0000,0000,0000,,is called the aortic valve.
Dialogue: 0,0:07:05.71,0:07:08.41,Default,,0000,0000,0000,,And the aortic\Nvalve is going to be
Dialogue: 0,0:07:08.41,0:07:13.34,Default,,0000,0000,0000,,what divides the left ventricle\Nfrom this giant vessel
Dialogue: 0,0:07:13.34,0:07:15.03,Default,,0000,0000,0000,,that we talked about earlier.
Dialogue: 0,0:07:15.03,0:07:17.53,Default,,0000,0000,0000,,And this is, of\Ncourse, the aorta.
Dialogue: 0,0:07:17.53,0:07:20.19,Default,,0000,0000,0000,,This is my aorta.
Dialogue: 0,0:07:20.19,0:07:22.11,Default,,0000,0000,0000,,So now blood is going\Nto go through the aorta
Dialogue: 0,0:07:22.11,0:07:24.21,Default,,0000,0000,0000,,to the rest of the body.
Dialogue: 0,0:07:24.21,0:07:27.92,Default,,0000,0000,0000,,So you can see how blood\Nnow flows from the body
Dialogue: 0,0:07:27.92,0:07:29.89,Default,,0000,0000,0000,,into the four chambers.
Dialogue: 0,0:07:29.89,0:07:33.29,Default,,0000,0000,0000,,First into the right atrium--\Nthis is chamber number one.
Dialogue: 0,0:07:33.29,0:07:35.04,Default,,0000,0000,0000,,And then it goes into\Nthe right ventricle.
Dialogue: 0,0:07:35.04,0:07:37.30,Default,,0000,0000,0000,,This is chamber number two.
Dialogue: 0,0:07:37.30,0:07:40.19,Default,,0000,0000,0000,,It goes to the lungs and then\Nback out to the left atrium.
Dialogue: 0,0:07:40.19,0:07:41.84,Default,,0000,0000,0000,,So this is chamber number three.
Dialogue: 0,0:07:41.84,0:07:43.72,Default,,0000,0000,0000,,And then the left ventricle.
Dialogue: 0,0:07:43.72,0:07:46.94,Default,,0000,0000,0000,,And this happens every\Nmoment of every day.
Dialogue: 0,0:07:46.94,0:07:48.85,Default,,0000,0000,0000,,Every time you hear\Nyour heart beating,
Dialogue: 0,0:07:48.85,0:07:51.52,Default,,0000,0000,0000,,this process is going on.