1.3b Heart Valves, Part 2

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From the course by University of Pennsylvania

Vital Signs: Understanding What the Body Is Telling Us

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University of Pennsylvania

Vital Signs: Understanding What the Body Is Telling Us

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The vital signs – heart rate, blood pressure, body temperature, respiration rate, and pain – communicate important information about the physiological status of the human body. In this six-part course we explore the anatomy and physiology underlying the vital signs so that you will develop a systematic, integrated understanding of how the body functions. Relevant body systems are reviewed including cardiovascular and respiratory, followed by explanations of how the function of these systems affects vital signs. We discuss normal ranges, normal variants, and the mechanisms that underlie changes in the objective measurement of vital signs. The course also includes demonstrations of appropriate techniques for measuring vital signs in yourself and others. The course is designed for a broad, general audience but will be particularly interesting for individuals working in healthcare, those considering a career as a healthcare professional, lay caregivers, those with an interest in personal health and fitness, or anyone who simply wants to understand how the body functions.

From the lesson

Week 1: Pulse/Heart Rate

This week we start our exploration of the vital signs with a look at the heart. We'll study the basic structure of the heart, think about how the heart pumps blood through the body, and learn how clinicians assess and think about heart rate and the pulse.

1.1 Basic Heart Anatomy 15:19

1.2a Your Beating Heart 10:54

1.2b ECG Demonstration 12:19

1.3a Heart Valves, Part 1 8:34

1.3b Heart Valves, Part 2 9:27

1.3c Assessing Heart Rate Demonstration 8:05

1.4a Cardiac Cycle, Part 1 6:48

1.4b Cardiac Cycle, Part 2 13:23

1.4c Assessing Pulse Demonstration 6:22

1.5 Cardiac Output 12:51

Meet the Instructors

Connie B. Scanga, PhD
Practice Professor
School of Nursing

[BLANK_AUDIO]

Okay so that's the first set of valves.

And I want to just now think

about something that Stef said which was the ventricles contract.

The AB valves will close and then blood will pass into

these big vessels that leave the left and the right atrium.

Right?

Blood will pass into the pulmonary trunk from the

right ventricle and into the aorta from the left ventricle.

Right?

Well, the opening into those large blood vessels is also guarded by valves.

And we call the valves that are positioned

at the opening into those large vessels semilunar valves.

The semilunar valves are being depicted on this model.

You can see that we have one at the entry

into the pulmonary trunk, and we call it the pulmonary.

Pulmonary semi lunar valve.

Sometimes it's simply called the pulmonic

valve.

At the opening, into the aorta it's a little

bit more difficult to see the semi lunar valve.

But you can see it tucked behind the mitral valve.

You see it?

that.

Semilunar valve is called the aortic

semilunar valve or simply the aortic valve.

Okay?

They get their name as semilunar valves, because the cusps of the valve

actually have a half moon shape when the cusps are closed.

Right?

>> Mm-hm.

Now, what happens is when these cusps are closed, they kind of fall

into the center pulmonary trunk, or fall into the center of the aorta.

And that prevents blood from flowing backward.

From the blood vessel into the ventricle.

[SOUND] >> But

what do you think makes those valves open?

[SOUND]

>> Is it the same sort of pressure concept?

That we talked about before?

>> Exactly, yes.

So when the ventricles are contracting, we know they're going to

eject blood into these large ventricles or into these large vessels, right?

And so when the ventricles contract and pressure

increases at the point that ventricular pressure is.

Is higher than pressure in these big blood vessels.

The semi lunar valves open, right?

And then, again, going back to our idea.

The idea of atria contract, ventricles contract.

And things relax.

During that relaxation at some point ventricular pressure

fall below the pressure in these big blood vessels.

And what will happen?

>> They'll close.

>> The semilunar valves will close.

Exactly.

Okay.

Now it's, it's a little bit more complicated because if you think about it

what's happening is during this [SOUND] [SOUND] relax.

When we're relaxed, which valves are open and which valves are closed?

Who wants to take a guess?

So during that relaxation time.

Mia.

>> Do the semilunar valves close, and the mitral, and tricuspid open?

>> Exactly.

So they, they will be in that state.

During that period, when, everything in the heart wall is.

Relaxed.

The AV valves will be open.

And the semi lunar valves will be closed.

And during that time, blood is going to be coming back into

the Atria through these big blood vessels that we talked about right?

So blood will come back to the right atria through which vessels?

The superior vena cava, the inferior vena cava, and the coronary sinus.

>> Right, and so that blood's coming back into

the right atrium because pressure's low in the right atrium.

Pressure's also low in the right ventricle,

and so the tricuspid valve is open.

And the blood is just going to flow

through the right atria into the right ventricle, right?

On the other side of the heart, things are equally relaxed.

And blood is coming back to the left atrium through which vessels?

>> The pulmonary veins?

>> The pulmonary veins, which are carrying

that oxygenated blood back from the lungs, right?

And the mitral valve is.

It's open because the pressure is low in all the chambers.

And so blood is flowing just flowing freely from the left atrium

through the mitro valve which is open into the left ventricle, right?

During that period when everything's relaxed though

we do not want blood flowing backward.

Through these vessels.

Right?

So, the semilunar valves are closed.

Fabulous.

Okay.

So, now, the next thing that happens, everything was

relaxed, now, we have this contraction of the atria.

That causes pressure to be a little bit higher in the atria, but.

Nothing really has changed in terms of valve status because of that, right?

But then the atria relax and the ventricles contract, and so now tell me,

when the ventricles contract what's the first valve change you ex.

Expect to see.

Nat.

>> The atrial ventricular valves will close?

>> Yes, exactly.

So during the first part of ventricular contraction, pressure in the ventricles

will become higher than pressure in the atria, and that will cause the av valves.

To swing shut.

Right?

OK.

And then pressure continues to climb as the

ventricles continue to contract, and eventually pressure in the

ventricles will be higher than pressure out here in

these big blood vessels, and what will happen Mina?

>> The semilunar valves will open.

>> Yes, and then we will start to do that thing the heart was meant to do.

[UNKNOWN] eject blood, right?

>> Mm-hm.

>> Into either the pulmonary or the systemic circulation.

Okay, and so then the ventricular contraction will stop and the ventricle

will begin to relax and what do you expect to happen first, Andre?

>> We'll have some [INAUDIBLE].

[INAUDIBLE] >> Exactly.

The semi lunar valves will close.

The ventricles will continue to relax.

And then, what will happen?

Steph?

>> The tricuspid and [INAUDIBLE] valves will open [UNKNOWN].

>> Excellent.

And so, it will all start all over again.

Because when those two AV valves.

Open but will be able to be passed from the atria into the ventricles, right?

It's kind of cool.

Now, you haven't thought about this before.

But when those valves close, [SOUND] they swing shut

and they cause vibrations to occur in the blood that's passing through.

For the heart.

And those vibrations get carried to the body's surface and you can actually, if

you listen with a stethoscope, you can

actually hear sounds caused by those vibrations.

And

we refer to those sounds as either sound one or sound two.

When the AV valve swings shut, it creates sound one.

When the semilunar valves shut, it creates sound two.

So, have you wondered what's going on when you're sitting in your

physicians office or you know, some

primary care specialist listening to your heart.

You guys know cause you've been practicing it right?

Yeah they, they can actually listen to hearts sounds at the body surface.

And those heart sounds are simply indicating that valves have closed.

This week in the simalab we're going to be practicing listening to heart sounds.

That would be pretty cool.

Any questions?

Okay.

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