clinical physiology week 3

Question 1

what are the chambers of the heart?

Answer 1

The left and right atrium

The left and right ventricle

The interventricular septum  the thick muscular wall that separates the left and right ventricle

Question 2

what are the great vessels of the heart?

Answer 2

The pulmonary trunk + left & right pulmonary arteries

The aorta

The superior and inferior vena cavae

The pulmonary veins

Question 3

what are the two types of valves of the heart

Answer 3

• atrioventricular and semilunar.

Question 4

what are the atrioventricular valves?

Answer 4

• Between the atria and the ventricles – prevent backflow

So when the left ventricle contracts, blood moves into the aorta, not the left atrium

So when the right ventricle contracts, blood moves into the pulmonary trunk, not the right atrium

Question 5

what are the semi lunar valves?

Answer 5

Semilunar (“half-moon”) valves

Between the ventricles and the great arteries

So when the ventricle relaxes during diastole, blood isn’t “sucked back” into that ventricle

Why does that arterial blood still move forwards? pressure gradient and elasticity of the walls.

Question 6

what is the structure of the AV valves?

Answer 6

Larger, and more “floppy” in nature

Anchored by the chordae tendinae

Keeps them from “flopping back” (prolapse) into the atria during ventricular contraction

Question 7

what is the structure of the semi-lunar valves?

Answer 7

Smaller and “tighter”

Therefore do not require chordae tendineae to anchor them

Question 8

what is the anterior heart composed of?

Answer 8

The anterior surface of the heart is obviously easier to auscultate and palpate than the posterior surface

Anterior surface – major structures

Part of the right atrium (auricle)

Right ventricle

The “tip” of the left ventricle

It’s the easiest place to palpate the cardiac impulse in most people

Point of Maximal Impulse (PMI)

The superior – lateral side of the left ventricle

Both semi-lunar valves are somewhat anterior to the AV valves  see next slides

Question 9

what point surface anatomy corresponds to the pulmonic valve?

Answer 9

2nd intercostal space, left sternal border

Corresponds to the pulmonic valve

Question 10

what point of body corresponds to the aortic valve?

Answer 10

2nd intercostal space, right sternal border

Question 11

where is the apex/ point of maximal impulse?

Answer 11

he apex (PMI) should be approximately at the 5th ICS, Mid-clavicular line.

Question 12

where is the best place to hear the sounds of the right ventricle and the right AV valve?

Answer 12

4th/5th intercostal space, right sternal border

Question 13

where is the best place to hear the left AV valve and left ventricular sounds and palpate the PMI

Answer 13

5th intercostal space, mid-clavicular line

Question 14

outline left atrium pressure;

Answer 14

A- theft atrium contracts (LA) helping fill the left ventricle.
B- the left ventricle contracts increasing pressure causing the AV valve to close hearing the first heart sound.
C- the LA fills as pressure is high in the left ventricle.
D- the pressure in the LV drops resulting in opening of the left AV valve.
E-LV fills.

Question 15

outline aortic pressure.

Answer 15

A: diastolic pressure prior to ventricular contraction.
B: The LV contracts the pressure increase over comes aortic diastolic pressure and aortic valve opens.
C: The LV applies maximal (systolic) pressure to the aorta.
D: when the LV pressure is less that the aortic pressure the aortic valve closes- second heart sound.

Question 16

outline left ventricle pressure:

Answer 16

A – the relaxed LV experiences a “bump” in pressure as the LA fills it

B – the LV contracts  pressure increase causes the left AV valve to close  the first heart sound (Lub)

C – The LV relaxes, and pressure starts to drop

D – When the LV pressure is less than the LA pressure, the AV valve opens

E – the LV fills

Question 17

what are the sounds we hear from the heart?

Answer 17

It’s always normal to hear a valve closing

AV valve  S1  “Lub”

This is a lower frequency sound, because the valve itself is a bit bigger and more “floppy”

Think of the largest string on a guitar

Semilunar valve  S2  “Dub”

This is a higher frequency sound, because the valve itself is a bit smaller and “tigher”

Think of the smallest string on a guitar

It’s uncommon to hear a valve opening

Some pathologies that affect the cardiac valves can result in “opening” sounds – they’re usually called opening snaps

Question 18

what is laminar flow?

Answer 18

• Blood flow can be smooth and orderly.
• and this is normal in the heart.

Question 19

what is turbulent flow?

Answer 19

-Blood flow can be rapid, forming disorderly eddies and vibrations.
It is often caused by valvular abnormalities, and can cause a variety of sounds

Murmurs

Extra heart sounds (sometimes)

It can be normal in some patients

Heart sounds are complex acoustical phenomena – we’ll address them simply today

Question 20

what is stenosis?

Answer 20

Stenosis – the valve doesn’t open widely enough

Higher pressures are needed to push blood through the narrow valve

The higher pressures cause “noisy” turbulent flow  a murmur

These murmurs are of course heard while blood is flowing across the valve… when the valve should be open.