Sign In | Subscribe
Start learning today, and be successful in your academic & professional career. Start Today!
Loading video...
This is a quick preview of the lesson. For full access, please Log In or Sign up.
For more information, please see full course syllabus of Anatomy & Physiology
  • Discussion

  • Study Guides

  • Download Lecture Slides

  • Table of Contents

  • Transcription

  • Related Books

Bookmark and Share
Lecture Comments (13)

1 answer

Last reply by: Bryan Cardella
Sun May 10, 2015 7:47 PM

Post by Syaza Yasirah on May 9, 2015

Hi Mr Cardella, thank you for posting this lecture of the heart.
I have a question relating to this topic on heart. If a person is fit, does his heart undergo structural and/or functional changes like cardio hypertrophy? And does the heart for such person undergo cellular events wyohich improves his heart's function?

Thank you!

1 answer

Last reply by: Bryan Cardella
Sat Mar 28, 2015 2:08 PM

Post by Emily Wilson on March 28, 2015

One part I didn't particularly like about this lecture was when you said the blood from the pulmonary arteries is bluish. I was under the impression that only the vessels were blue and blood was always red?

2 answers

Last reply by: David Gonzalez
Tue Jan 13, 2015 8:41 PM

Post by David Gonzalez on January 13, 2015

Hi Mr. Cardella, thanks for the great lecture.

Why does the left side of the heart have only a bicuspid valve while the other has a tricuspid valve (speaking from an evolutionary standpoint)? Does it have something to do with the the rate of blood flow? Type of blood (oxygenated vs. deoxygenated), etc.?


1 answer

Last reply by: Bryan Cardella
Wed Jul 2, 2014 4:42 PM

Post by David Gonzalez on July 2, 2014

Great lecture! I have one question: does the blood in the right ventricle always leave through the pulmonary valve while blood in the left ventricle always leaves trough the aortic valve? And when it leaves, where does it go? Thank you!

0 answers

Post by Neil Gill on March 9, 2014

Crystal clear. Thank you very much.

2 answers

Last reply by: Sandra Egwuonwu
Sun Mar 16, 2014 8:00 PM

Post by Yanet Ortiz on February 25, 2014

in the slide about heart beats and valve you have the  atrioventricular valve are the bicuspid and mitral? is that correct?I think it is tricuspid and mitral!!
thank you for your lectures!! very helpful

The Heart

  • Heart anatomy includes the pericardium, epicardium, myocardium, endocardium, atria, ventricles, coronary arteries, arteries/veins, and fat
  • The sequence of blood flow (beginning with blood returning to the heart from the body): vena cava, right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary arteries, lungs, pulmonary veins, left atrium, bicuspid (mitral) valve, left ventricle, aortic valve, aorta, body
  • The heart beat sounds (lubb-dubb) correspond to the atrioventricular valves and semilunar valves closing simultaneously
  • Systole is contraction, diastole is relaxation, and cardiac output is calculated by multiplying stroke volume times heart rate (beats per minute)
  • Cardiac conduction system works via the sinoatrial (SA) node, the atrioventricular (AV) node, the AV bundle, and Purkinje fibers
  • Electrocardiograms (how the electricity within a heart is measured) involve P waves, QRS complexes, and T waves to diagnose arrhythmias
  • Heart conditions/disorders include myocardial infarctions (heart attacks), angina pectoris, fibrillation, and heart murmurs
  • Did you know…
    • Q: Are heart murmurs always deadly?
    • A: No, the severity of a heart murmur varies. Severe ones can be fixed surgically to replace a defective valve with a cadaver valve or pig valve. Other people have minor murmurs and only feel negative effects (fatigue, fainting) when their heart rate is very high.

The Heart

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Heart Anatomy 0:04
    • Pericardium
    • Epicardium
    • Myocardium
    • Endocardium
    • Atria and Ventricles
    • Coronary Arteries
    • Arteries / Veins
    • Fat
  • Sequence of Blood Flow #1 5:06
    • Vena Cava
    • Right Atrium
    • Tricuspid Valve
    • Right Ventricle
    • Pulmonary Valve
    • Pulmonary Arteries
  • Sequence of Blood Flow #2 8:22
    • Lungs
    • Pulmonary Veins
    • Left Atrium
    • Left Ventricle
    • Bicuspid Valve
    • Aortic Valve
    • Aorta
    • Body
  • Simplified Blood Flow Diagram 11:44
  • Heart Beats and Valves 16:09
    • 'Lubb-Dubb'
    • Atrioventricular (AV) Valves
    • Semilunar Valves
  • Systole and Diastole 19:09
    • Systole
    • Diastole
    • Valves Respond to Pressure Changes
    • Cardiac Output
  • Cardiac Cycle 22:59
  • Cardiac Conduction System 24:52
    • Sinoatrial (SA) Node
    • Atrioventricular (AV) Node
  • Electrocardiogram (EKG or ECG) 28:46
    • P Wave
    • QRS Complex
    • T Wave
    • Arrhythmias
  • Heart Conditions / Treatments 35:12
    • Myocardial Infarction (MI)
    • Angina Pectoris
    • Pericarditis
    • Coronary Artery Disease
    • Angioplasty
    • Coronary Artery Bypass Graft
    • Tachycardia / Bradycardia
    • Fibrillation
    • Heart Murmur
    • Mitral Valve Prolapse

Transcription: The Heart

Hi and welcome to

This is the lesson on the heart.0001

When we look at the anatomy of the heart there are other several layers we need to consider.0003

The pericardium is technically not the heart itself.0009

What we can see here is it is kind of cutaway.0014

This is pericardium in cutaway is this connective tissue sacked that in a person's thoracic cavity.0017

If you are open them up you would see almost like a ceramic wrap more opaque than that around the entire beating heart.0026

That particular connective tissue sack is not only protecting the heart and giving it some extra layered cushioning but 0036

in between the pericardium and the surface of the heart itself is fluid and that is providing lubrication.0045

Think of it as the engine of your car, without oil in the engine with all those moving parts that are met along the middle, it would not quite as well.0051

It would be too much friction.0061

Having that fluid in between the inside of the pericardium and surface of the heart is very important.0062

The epicardium, remember epi means superficial when we are talking about organs in the outside.0068

The epicardium is the actual surface of the heart.0075

It is very thin in terms of the rest of the layers.0078

When we go deeper the myocardium, the thickest layer the heart by far is all that muscle.0082

That cardiac muscle is very thick.0089

If you have ever cut in two of a sheep heart or cow’s heart it will be a lot bigger in some dissection.0092

The myocardium is very thick and it is important.0098

You want it to be strong.0102

You want it to last a lifetime and do the job of making blood move.0103

The endocardium is that inner layer, the deepest layer of the heart tissue.0108

It is very smooth like a slip and slide.0114

A very smooth made up of epithelium and you can call it endothelium because very deep.0117

That is what the blood itself is slipping and sliding along and you want it to be smooth.0122

If the endocardium was rough it would damage or rupture too many red blood cells.0128

You want it to be nice and smooth for this process to work properly.0132

The atria and ventricles are the main chambers of heart.0137

You could see here this is the right atrium, from this view it is hard to see the left atrium.0140

It is over here they say oracle of the left atrium, that is just the corner of it.0145

If we turn the heart slightly you will be able to see the left atrium a lot better.0152

But those are the most superior smaller chambers of the heart.0156

If we go deeper you would see the right and left ventricle larger chambers.0160

The way I keep it straight in terms of right and left is just to keep in mind that this is from the point of view of the person who is heart this the lungs to.0165

From my point of view, if you look at the heart, my left ventricle is on that side and I know it is your right but we got to keep in mind it is from the point of view of this object.0175

That is why even on the left side of the drawing you know this is called the right atrium.0186

The right ventricle would be in here.0191

Just keep that in mind.0194

If you are looking from the posterior side, you are looking from behind then your left would be the same left as the subject.0196

The coronary arteries is a general term for these blood vessels that supply the heart muscle tissue itself with blood.0204

This is an interesting thing to think about.0213

The heart itself needs blood as well.0214

The hearts role is to circulate blood to the entire body, to all the cells that need it.0217

But the heart itself does not get blood it will not get the nourishment.0224

It will not get the sugars and gas as it needs to be able to keep providing the sugars and gases to the rest of the body.0227

The coronary arteries are very important.0235

You have blood flow coming out of the inside that is called the aorta to get all of that blood inside of those muscle fibers.0237

If you get a clog, if you get a blockage in the coronary arteries you get a heart attack.0247

There are arteries and veins coming out from the top portion, the superior portion of heart.0254

The major one is the aorta, that is the major artery that sending blood to the body and then there are veins as well.0259

We will get to those in more detail on future slides in this lesson.0267

Lastly fat, all of this yellow stuff that is lipid, that is fat.0270

You are going to see it on the surface of the heart.0276

You are also going to see it around the outside of our heart especially around the pericardium as a cushioning.0278

You want to cushion it in the thoracic cavity.0284

It is a very precious organ.0287

You do not want to get damaged.0289

Having some of fat is a nice little buffer, cushion.0290

The fat on the outside here, I want you to think this person is unhealthy.0294

It is normal to have some fat on the outside.0298

The fat you do not want is inside the coronary arteries.0300

We look at how blood flows to the heart.0304

It should be a one way trip meaning one way street is a better way to say it.0310

You do not want backflow.0317

We will talk more later about what the backflow is and how that happens.0319

When we start with blood coming back from the body into the heart, it is the Vena Cava that is taking blood from above the heart from below the heart back into it.0323

You want the blood going back in the heart so it can send it to the lungs where you can exhale CO2 as accumulated in the blood.0334

And get O2 back in the blood and send them back out to the body.0341

The vena cava is here and here.0344

You can see it on the right side of the heart.0349

Remember the right is actually your left when looking at this person's heart.0351

This is the inferior Vena Cava which is taking the oxygenated blood.0355

It has more of a blue look to it, from all of those veins that are below the heart taking all that back into this chamber 0359

and this is the superior Vena Cava taking the oxygenated blood from the areas above heart into this chamber.0369

This is the right atrium.0378

Once blood enters the right atrium there is a little door way that separates this chamber from the right ventricle.0380

This doorway is called the tricuspid valve because when you look down on this valve, these are flaps that open and close.0387

It looks like this kind of like a Mercedes symbol.0393

This is a cuspid and all these flaps there are 3 of them that is why it is a tricuspid valve.0400

The right ventricle is the larger chamber.0408

If that tricuspid valves opens and this chamber contracts or squeezes, blood is going to enter into here.0412

You can see that associated with each of the valves are these little strands called corti tenamae.0419

I will tell you more about those in a bit.0424

Once blood enters the right ventricle and in the right ventricle squeezes it is going to shoot it out through the pulmonary valve.0426

The word pulmonary always has to do with lungs.0433

This valve is going to be allowing blood to pass through it and then eventually go on to the lungs.0436

The pulmonary arteries are those blood vessels that are taking blood to left and right lung.0442

You can see that there are two parts of it.0447

It is like a fork in the road.0450

This goes to the left and this goes to the right.0451

Arteries are always leaving the heart.0454

It is taking blood away from the heart.0459

I have heard students have misconception for it and I used to have misconception as a student that arteries are red, veins are blue.0461

In the systemic circuit going to and from the body that is true but it is flipped in the lungs.0467

When you take blood away from the heart to the lungs it is actually bluish because it is lacking oxygen.0474

When you go to the lungs and pick up oxygen and take the blood back to the heart those veins have a red blood.0481

Remember arteries are always leaving the heart, veins going to the heart.0488

The lungs are the next destination.0494

Let us go to the next slide to see the rest of the sequence on the left side of the heart.0497

The sequence of blood flow from the lungs back to the heart is going to take oxygenated blood.0502

See this pink arrow through the left pulmonary vein and to the right pulmonary vein into this chamber over here.0509

This is the left atrium.0517

This little red guy here looks like it is coming into the right side of the heart.0519

If you look carefully this particular vein coming from the right lung goes just behind these other blood vessels and does connector right here to the interior of the left atrium.0524

Blood passing through that atrium into the left ventricle is going to go through once in another valve that prevents backflow.0538

And that valve is called the bicuspid valve because this particular valve has only two cusp not 3.0546

A nickname for this valve is the mitral valve.0554

I will explain why.0559

The mitral valve is the same thing as the bicuspid valve.0561

Someone who named this knew this was very creative in terms of imagination.0565

They thought that this valve reminded them of a maître.0569

And a maître is one of those bishop or pope’s hats.0572

He may be familiar with this and one of these kinds of hats.0576

There is the blue skull cap part and here is the guy.0583

Any ways, those two parts of the hat is something about has reminded them of that.0586

You can call bicuspid or mitral valve.0596

In text books they refer to both terms.0598

That particular valve is controlling backflow so that when this left ventricle squeezes, when it contracts you do not want blood going backwards.0602

You want it to be going out through the aorta.0613

There is a valve that prevents blood from going back and left atrium wanted to reach this blood vessel.0616

The left ventricle when it squeezes blood goes through this particular valve here.0623

It is hard to see but there are also has 3 cusps.0627

The aortic valve is going to lead to the aorta, the largest, strongest artery in terms of its thickness in the body.0630

The aorta in the average person is about the thickness of a garden hose.0639

Picture a garden hose right there looping above your heart, that is crazy to think about.0643

You want it to be tough and strong because blood is rocketing out of the heart through that.0649

You do not want to tear.0655

It is very unlikely that the aorta is going to tear because it is so strong but severe traumas and with a car accident could tear it.0656

A tear in the aorta could cause someone to die very quickly because of the amount of blood 0665

that would be coming out will be quite a lot in terms of on how quickly would exits that blood vessel.0672

The body is the next destination.0678

You can see that the aorta it has these little arteries that come out from the top of the superiorly taking blood to the arms, 0681

Taking blood up into the head, and then the rest of the blood goes down was called the descending aorta which goes behind the heart.0690

It is going to split up into all the major arteries going to the rest of the body.0698

I have this simplified blood flow diagram that I drew because when we look at the heart and how twisting and turning it is, 0702

sometimes it is hard to remember what leads to what.0710

I am going to give you some hints and abbreviations here that will help.0714

I will use blue for the left side.0717

Keep in mind this is a boxy depiction.0719

This is not anatomically accurate in terms of the space involved in terms of the angles and such.0724

But the sequence is going to be the same.0731

Here is the superior Vena Cava.0735

Here is the inferior Vena Cava.0738

As we taking blueblood, deoxygenated blood back into the heart that is why I am using blue here so they both lead into here.0742

Here is the right atrium.0751

This little doorway is the tricuspid valve that leads into the larger chamber that is inferior to the right atrium, the right ventricle.0755

Here is a hint for remembering what side the tricuspid valve is on.0769

TV RV, you can watch TV in your RV.0773

That is a way you can remember it.0779

The tricuspid valve is providing backflow from the right ventricle into the right atrium.0782

Since this is taking blood to the lungs because it is blue we want to get that oxygen back.0788

You can call this the pulmonary valve.0794

The blood is going this way to the pulmonary valve leads to the pulmonary arteries because it is taking blood away from the heart.0799

Here is the left pulmonary artery and here is the right pulmonary artery.0810

That blood goes to the lungs gets through the CO2 in it so that you can exhale it.0824

Picks up the oxygen and when oxygen attaches to hemoglobin which you are going to hear more about in the blood lessons, it becomes red.0829

How do we get back in the heart?0835

We are now on the superior left side.0840

This would be the left pulmonary vein and over here because it is going behind the heart into this region of the atrium.0843

This would be the right pulmonary vein.0856

And both of those blood vessels lead into the left atrium.0862

Remember this one was not tricuspid like over here.0870

It only has 2 cusps so this is the bicuspid valve also known as the mitral valve.0874

Down here is the left ventricle, this is the largest chamber in the heart.0880

It is slightly larger than the right ventricle depending on what anatomical image you see with cross sections through it.0889

Depending on how interior or posterior they are sometimes the right ventricle will appear larger depending on what angle and what part of heart you are cutting through.0897

But left ventricle is slightly bigger than the right ventricle.0906

The blood flow comes in here, comes through here, and then it is going to go up.0910

Once the left ventricle contracts, this is the aortic valve and that takes blood into the aorta.0918

The blood going through here, if you kind of think the aorta comes up and has that little loop that goes down, 0929

this looks like an A if you look at how the left pulmonary artery goes in front of it.0945

It is a nice way to remember that A for aorta, that major blood vessel taking oxygenated blood into the entire body.0952

There are also arteries that branch off from the top.0960

There is a simplified blood flow diagram for you.0964

When we look at the heart beats and the valves and in how the actual sound of a heart corresponds to the valves closing and opening, 0968

a lot of textbooks will refer to be the lubb dubb and the sound is actually corresponding to the valves closing.0977

The first sound is actually these valves closing.0989

The lubb is these 2.1002

These are known as atrioventricular valves or AV valves.1005

A way to remember that is they are separating the atria and the ventricles.1008

Atria ventricles so it is atrioventricular valves separates the A and V that is why they are AV valves.1012

Bicuspid or mitral or bicuspid and tricuspid.1019

The other 2, the pulmonary valve and the aortic valve are semilunar valves named after a half moon term.1022

The semilunar valves are these two and so these close together and these close together and you can see that when the AV valves are open these are going to be closed.1032

When these are open these are going to close.1042

This picture by the way, for which one is it is the aortic valve but the tricuspid and pulmonary valves are very similar.1045

Think of it this way.1054

The lubb start with the valves that happened kind of first in terms of thinking about blood coming in.1057

Remember blood coming into the heart neither side, it is going to pass through these valves first.1069

Think about them closing first in terms of the sequence of lubb and dubb.1075

Because these 2 closes for that first sound, they close when the ventricles squeeze.1081

Why do they close when the ventricle squeeze because if you are matching blood pooling into these parts the walls just compact together.1090

You want blood to go which way, this way and this way, not back.1099

You do not want it to go backwards into the atria.1107

When this contracts these too, the bicuspid and tricuspid or AV valves have to close.1109

Conversely when these are relaxed and you want blood coming out of the atria down to the ventricles so you want these to be open.1116

You also want these to be close that time because you have just squeezed blood out of the ventricles 1127

and you want it to stay on its way into the lungs and outside the body in these blood vessels.1132

You have to have that coordinated opening and closing.1139

Systole and diastole.1143

When we look at the terms systole that is basically saying contraction.1151

When the ventricles contract they are in ventricular systole.1156

Diastole is the opposite.1162

When the ventricles relax it is what you call diastole.1164

When ventricular contraction or systole is happening you are going to get the atria doing the opposite and vice versa.1168

You can use the term atrial systole and atrial diastole.1176

It is contraction vs. Relaxation.1181

The chambers are going to relax when they are ready to receive blood.1185

Think about the ventricles.1188

When they have just shot blood out of the heart they then need to be ready to accept blood from the atria 1189

so they are going to relax and open up to get the blood pooling in there.1195

Once again it is systole.1199

The way that I keep this straight is blood pressure terms like the blood pressure 120/80 that is systolic/diastolic.1201

That higher number corresponds to higher pressure contraction.1210

Systole that higher number 120 or whatever the systolic number of blood pressure would be for a person is going to be a higher number 1215

because it is contraction rather than that relaxations which is going to be lower pressure.1223

The valves will response to the pressure changes.1228

I told you I would tell you more about those little tendons.1231

There are little white strands associated with the valves as they open and close.1234

As ventricular pressure rises, as they contract above the atrial pressure that causes the AV valves to be pushed close.1240

When the ventricles relax and expand that pulls on those little white tendons that are called cordae tendonae.1250

Remember tendons connect muscle and bone.1267

These are a little a bit different than your average tendon because it is connecting valves, part of the endothelium of the heart 1270

to other parts of endothelium that are all connected to the myocardium or the heart muscle itself.1278

As the pressure changes, because of the contraction and relaxation that is going to open and close the valves because these are attached to those little flaps.1285

Cardiac output you are going to hear more about that in blood pressure, parts of the blood vessel lessons.1294

The cardiac output is a measure of how much blood is physically leaving the heart.1301

Stroke volume is milliliters of blood that leave the heart with each ventricular contraction or ventricular systole.1307

So how much blood is physically leaving.1316

And then of course how often it is leaving?1319

Heart rate we are talking 60 beats per minute which is resting heart rate for all people.1321

Are we talking 130 beats for minute which is when somebody is typically doing some running.1326

It can even be a lot higher than that.1331

Cardiac output can be increased by having just a lot higher heart rate.1334

Just having your heart beat faster the amount of blood coming of the heart would increase of course.1339

If you can increase stroke volume you do not have to have this much of a heart rate increase.1345

How you do you increase blood volume?1350

A lot of exercising.1351

If somebody gets to the part where their heart is super efficient in terms of how much blood can actually squeeze out with each beat, 1353

you will find that their resting heart rate tends to drop because when their at rest their body does not need to have as many contractions.1361

Because with each contraction they are actually squeezing a lot more blood.1370

Here is a picture of the cardiac cycle in terms of pressure in the aorta, pressure in the ventricles, how much blood is in the ventricles.1377

This is showing you in ECG Electrocardiogram and then a photocardiogram in terms of the sounds coming out of the heart.1390

Aortic pressure related to ventricular pressure.1398

Let us look at this.1402

When you get the ventricle contracting doing systole that is when you get this blue rise and that corresponds to ejection or letting go of blood out of the ventricles.1403

And that is going to increase the amount of pressure in the aorta because where is this blood going when the ventricle contracts?1416

It is going in the aorta sending the blood to the rest of the body.1423

At the same time when the ventricle squeezes that is why this red line drops.1426

As soon as this rises the amount of blood in the ventricle lessens because that blood is leaving the ventricles.1433

You will see more about this later in the lesson.1441

What is this little bump, all those heart monitors, what is that mean?1444

We are going to get to that in a second.1452

I just wanted to show you how it is all related here in terms of when the ventricles are squeezing and letting blood out of them.1453

At the same time when the ventricles go back to diastole in terms of relaxing the pressure lessens 1462

and then once they are open up again and waiting for blood, what is going to happen?1470

Ventricular volume is going to increase because the atria on the top are squeezing blood back in the ventricles and that is going to happen all over again.1475

And this happens in a matter of 2-3 seconds or even less when the heart rate is very fast.1483

When it comes to initiating a heartbeat it is really fascinating within the heart.1490

Automaticity this term here means that this is the one place in the body where electrical signaling happens apart from neurons initiating it.1497

You will get movement of this amazing organ without neurons specifically being inside of it.1509

A misconception some students will have as they think that the cardiac induction system is a bunch of neurons or nerves within the heart.1516

That is not true.1523

There are pathways within the tissue of the heart, within these muscle fiber tracks that died the electricity through it.1525

And that is described as the cardiac conduction system.1534

This describes how electrical signaling makes its way to the heart in a coordinated fashion. 1537

We hope it is coordinated.1541

The sinoatrial or AS node is the little blueish purple dot right here.1542

I am going to underline that in blue that is located in the superior wall of the right atrium.1548

This is interesting looking drawing and in this particular shot we cannot see the left atrium very effectively 1558

but the left atrium does not have much to do with starting up the heartbeat.1568

This sinoatrial node is extremely important because this is the natural pacemaker of your heart.1573

You may have heard somebody having a pacemaker that is an artificial pacemaker where 1579

we have attached electrical device to the heart that helps initiate the heart beat in a proper way.1583

Somebody is having some trouble with their SA node working naturally you then attach a pacemaker to it to keep it in check.1590

This is the natural pacemaker that we are born with.1598

Some people have no trouble with this pacemaker their entire lives.1605

It is doing the proper coordinated well paced set of contractions and relaxations supposed to happen.1610

There is nerve that comes and stimulates the SA node and then once that is stimulated it is off to the raise 1618

in terms of the electrical signal flowing through the heart in the right way.1625

The SA node then sends a signal into here the AV node so this is more in the inferior parts of the right atrium.1629

I will do that in red, the atrioventricular node.1639

Remember the term AV valve from the previous slide, AV node has its name because you can see that if it is on the inferior part of the atrium 1644

that is going to be adjacent to the opening to the ventricles that is why it is called AV nodes it is very close to the opening to the ventricle.1654

Here is a good image of the cordae tendonae.1662

The AV bundle then takes the signal down through the septum meaning the border between the left ventricle and right ventricle.1667

It extends in what are called perking fiber.1678

All these little fibers that are intervening the muscle fibers in the ventricles named after a Dr. Perkinge 1681

and those perkinge fibers when the electrical signals goes through all those you get the left and right ventricles contracting at the same time as they were supposed to.1688

If you are wondering, what about the left atrium?1698

Because of signals going through the SA node is able to simultaneously stimulate through these little tracts.1701

The atria contracting just about the same time.1710

This sequence is able to get the atria and ventricles contracting in a coordinated fashion to make sure that blood is flowing properly and efficiently through the heart.1715

EKG or ECG stands for electrocardiogram.1726

The English abbreviation the ECG and EKG comes from the German for cardio.1731

You can use either one EKG or ECG they are the same thing. 1738

This is a measure of electrical events in the heart.1741

When we look at one single woot there are a few different points they call them waves.1743

The P wave which we will do in red right here, this has to do with the atria being depolarize.1749

Depolarize in atria is going to make it do atrial systole that contraction.1760

Here is atrial depolarization.1766

That is going to make the left and right atria contract.1774

You noticed it is a little hump.1781

It is a little change in electricity and the up flowing through the part compared to this because the QRS that is the ventricles.1783

If you remember why this bump is always high?1792

Ventricles are much larger in terms of them being this holder of blood and like the muscular chamber that is going to be in a much stronger way squeezing blood out of the heart.1794

The size of those ventricles, the amount of electricity flowing through them is going to be a bit bigger.1807

The QRS complex, that as a whole from this point up here and down this is ventricular depolarization.1813

All of these.1823

Remember the terms repolarization and depolarization from action potentials it has to do with this.1824

With action potential it goes up and down similar to this where it is depolarization repolarization terms of sodium and potassium.1843

You can use those terms here to help you remember that it is a depolarization then repolarization.1853

Sodium is going into the neuron potassium leaving the neuron.1860

Having depolarization repolarization this whole thing here just itself as depolarization, after it you have repolarization 1864

that gets the ventricles back into their relax state and gets them in ventricular diastole.1874

The T wave is actually the event that repolarizes the ventricles eventually getting ready for receiving more blood.1881

This is ventricular repolarization.1890

If you are wondering what happened to atrial repolarization?1896

I do not see that here.1906

It is covered by QRS so the repolarization in the atria actually happens during the span of time but the electrical signals of the ventricles just outweighed it by far.1907

In an ECG you are going to notice this overlapping that.1917

In terms of arrhythmias I am going to show you how this ECG reading can vary and how a doctor can interpret it in terms of what is going on within heart.1921

First one is what you are seeing here is instead of there are being a nice flat line between the heartbeats you see squiggly and then QRS quiggly.1932

What are these squiggles?1955

That is called atrial fibrillation.1956

The atria instead of having nice coordinated contractions and relaxations, they are kind of not doing it very well.1959

This is not necessarily deadly.1966

It is something that you obviously do not want happening but as long as the ventricles are getting enough blood going in them and1969

doing a great job of squeezing which looks like they are, people can live a long time with some atrial fibrillation.1976

It means their atria are not doing the best job but at least you get the QRS wave.1983

Something else that can happen is, let us say you have the normal flat line between beats and then this.1989

Notice here that the QRS is not that big.1995

It is really not that much bigger than the P or T.2003

This means you can have a weakening of the ventricles.2006

They are not doing as good a job as the most profound systoles, those contractions getting blood exiting.2010

That can be a problem.2018

Here is another one.2020

Notice that is a lot bigger QRS exaggerating little more.2021

This is a sign of an enlarged heart.2036

At first you might think a larger heart is doing even better because it is bigger.2039

An enlarged heart having an enlargement of the ventricle mass of the ventricle muscle is actually counterproductive.2046

An enlarged heart I also have the term athlete's heart to describe it.2055

Getting an enlarged heart there actually can make the ventricle chambers smaller.2059

Its ability to get blood exiting the heart efficiently it is going to get in the way of cardiac output.2065

Having enlarged heart is not a good thing.2071

There are plenty of other arrhythmias in terms of the spacing between the P and S, spacing between the S and T.2074

That could signal problems in the cardiac conduction system that the electrical signal from SA to AV is somehow not going as quickly as it should.2082

Or from the AV down the bundle for deceptum and the perkinge fibers, if any of those are delayed you got problems with the coronation of your heartbeat.2092

There are other things like tachycardia, bradycardia, with have to do with too high of a heart rate and too low heart rate.2102

We will cover that at the end of this lesson.2109

Heart conditions and treatments.2112

A myocardial infarction or MI is something you might hear in certain medical shows or shows involving doctors or something in a hospital.2114

That is a heart attack.2123

A myocardial infarction is a technical term for heart attack.2125

The way it happens is a blockage in a coronary artery is going cut off blood flow to part of a heart tissue 2128

and it is going to cause death of some of the heart tissue within the myocardium.2135

You can survive a heart attack but the more heart attacks a person gets the more you are permanently damaging your heart tissue.2140

The more heart attacks the more likely is that the next one can be fatal.2146

There are interesting bits of research the leading us into how to regenerate heart muscle in an area of the heart that is dying off because of a heart attack.2151

I have read that injecting stem cells into on mice or rats heart that have myocardial infarctions has shown promise.2161

I think we will eventually get the point where we will be able to bring back a dead heart issue.2171

Your diet, exercise, are going to be those things that you do have control over right now.2176

Angina pectoris is not quite a heart attack.2182

Angina pectoris has to do with a lessening of adequate blood flow through those coronary arteries so that 2185

you do have periods of time if somebody has angina where the heart is not getting as much blood as it should.2193

Typically some of the angina if they get really stressed out, really angry, or do too much physical activity, the increase in blood pressure and 2200

the constricting of the coronary arteries is going to cause them a lot of pain because it is not quite in MI 2208

but you are restricting blood flow to the parts of the heart that need blood in order the contract effectively.2214

One of the treatments for angina pectoris is something like nitroglycerin.2219

I have heard of sprays under the tongue, there are other ways to deliver it in the body but it will actually the lower the blood pressure 2225

which will make all those coronary arteries expand a little bit and then have more blood can get to the heart. 2234

Interestingly enough a little blue pill that people are familiar with which is actually corrects all dysfunction is related to this.2240

One of the active ingredients in medications the tree angina pectoris since it lowers blood pressure and actually expands the vessels getting more blood flow.2250

They notice one of the side effects of treatment in angina was the males would get erections now and then.2261

Taking that active ingredient and playing with it in terms of what tissue it targets that led to that pill that helps with ED 2268

because it is expanding blood vessels and helping get blood flow into the penis and that is $1,000,000,000 industry.2277

Pericarditis is actually infection or irritation of pericardial, that sac around the heart.2286

It can get irritated because of trauma or an infection can harm that and overtime that can have a negative impact on heart which is inside it.2293

Coronary artery disease is what is going to lead to an MI.2304

A coronary disease when you get a buildup of plaques that are constricting the amount of blood that can go through those blood vessels.2309

That is something that is not good to get and of course like I have mentioned diet and exercise are important.2318

An angioplasty is one of the most common ones.2325

I have heard there is a balloon angioplasty.2328

It will actually go through the femoral artery in the leg and they will insert this little metal like catheter and it goes all the way up into the aorta.2330

And they go up around that little loop into a coronary artery where they have a blockage and then they will actually go into the coronary artery 2343

that has the plaque and then expand the balloon that will actually press that plaque out of the way and it gets that interior part of the blood vessel expanded and open.2355

That is a fascinating thing to think about that they can actually increase blood flow and make it less likely that person is going to get MI in the future.2367

It is something that is not a permanent fix.2377

If a fat person continues to eat a high fat diet so he has high saturated fat and does not exercise, they are going to get the buildup of plaque again.2381

It is not going to cure the problem. 2391

The coronary artery bypass graft.2393

If you have ever heard somebody getting a triple bypass or quadruple bypass, when they do a surgery to take an artery and had a goal around where there is a blockage.2395

You may have up to 4 once be done so a quadruple bypass is a major thing because they are making the loop for blood to bypass 2406

so they go around a blockage in the road that is taking blood into the heart muscle.2416

That graft can definitely extend someone's life significantly.2420

Amazingly some people better than others will naturally do this in their heart.2426

Some people just go beyond 90 hundred years without getting a heart attack because where they had a blockage their body can actually naturally bypass, go around that blockage.2433

Some people do better than others.2447

Tachycardia vs. Bradycardia this means really high heart rate versus really low.2449

Tachycardia is acceptable if you are exercising or if you are running, if you are doing a marathon you are going to have a high heart rate.2456

Tachycardia in that instance expected.2463

Bradycardia if your at rest you would expect to have a very low heart rate but if your tachycardic, if this is happening when you are at rest that is not a good ting.2466

It might be stress.2479

It might be something that is causing that to happen is very unhealthy.2480

If you are tachycardic and when you are sitting down and you want to go to the doctor to get the checked out.2485

Maybe stress that is causing that.2491

Bradycardia having too few heart beats in a span time.2493

Like I have said, when you are at rest it is expected but you want your heart rate to increase if you are asking your body to do more.2502

That is how you are going to get more blood flow into your skeletal muscles.2510

Fibrillation is something that is going to be accompanied with MI.2514

Fibrillation is associated with it.2520

What I mean by that is if you have the cutoff of blood flow into significant part of the ventricular muscle 2524

instead of it being this nice coordinated set of your PQRST it is going to look like this.2532

That is not effectively contracting ventricles and contracting and relaxing the atria.2539

This is what a heart attack can look like and that is called fibrillation.2546

An AED or an automatic external defibrillator is the clear and that is trying to kind of reboot the heart in terms of the electric flow.2550

Trying to get back into this proper PQRS complex.2564

An automatic external defibrillator is the opposite of fibrillation.2570

De for trying to get rid of that fibrillation so it has a nice coordinated set of contractions.2574

If someone is flat line just no electricity flowing to the heart, the chances of an AED getting them back is extremely low.2580

It is possible so they are still going to try to give that person back but generally AED is most effective in getting a person out of fibrillation.2591

A heart murmur is when one or more of the valves that control blood flows that goes in one direction is not working properly.2599

If those valves, the AV valves or semilunar valves are not completely closing when they should, you can get regurgitation.2609

Blood flow going backwards.2618

A heart murmur you can go to a cardiologist and they listen to your hearts sound with a stethoscope.2620

They are trained and have tons of experience where they can hear the little bits of backflow in a heart murmur.2627

I do not have that training but I'm exaggerating this for you.2634

A heartbeat to them would sound like bump bump bump and if we exaggerate what a heart murmur sounds it is like bump shh bump shh.2637

Because that shh sound is blood back flowing, going backwards maybe back into the ventricle from the aorta.2648

Or some of it ends up staying behind in the atria rather than going from the atrial ventricles.2660

Heart murmur sometimes if it is significant enough overtime that can shorten lifespan and surgeries can replace them or fix them.2665

They actually will use fake heart valves oftentimes to replace heart valves in human and that works fine.2677

But you have to take drugs to calm down your immune system so you do not attack that issue but it works.2685

Mitral valve prolapsed is when part of the mitral valves actually like going curved into the atrium.2692

Mitral valve prolapsed over time it is not sufficient in terms of the mitral valve closing when it is supposed to prevent backflow.2701

These are some of the heart conditions and treatments involved with keeping a person alive and in minimizing problems with the heart.2710

Thanks for watching