Cardiac Cycle & Heart Sounds

Question 1

During ventricular systole, what happens with ventricular volume and pressure

Answer 1

Volume decreases and pressure increases until amount of blood (volume) is depleted, then pressure begins to fall

Question 2

What does ventricular systole occur on the EKG

Answer 2

From the QRS to the end of the T-wave

Question 3

When does ventricular diastole occur on the EKG

Answer 3

After the Twave

Question 4

What is the typical Ao. Pressure

Answer 4

120/80

Question 5

What is the typical Ventricular pressure

Answer 5

120/0

Question 6

The amount of blood that is ejected from the ventricles during systole is known as what

Answer 6

The strove volume

Question 7

What does atrial contraction mean in terms of atrial pressure and volume as well as ventricular volume and pressure

Answer 7

Atrial pressure increases
Atrial volume decreases

Ventricular volume increases
Ventricular pressure increases

Question 8

Why is the P wave included in the PR interval

Answer 8

Due to the delay of the muscle contraction

The electrical conduction reaves the AV Node first before mechanical contraction occurs.

Question 9

After the atria contract and begin to relax, what happens with pressure and volume in in the ventricles

Answer 9

The ventricles start to contract and pressure increases, but volume does not change right away

Question 10

The QRS complex represents what phases in ventricular conduction

Answer 10

Phase 0 and 1

Question 11

The ST segment represents what in terms of ventricular myocyte activity

Answer 11

Phase 2 - the plateau

Question 12

Why does the ventricular pressure drop while the ventricles are still contracting

Answer 12

Less blood (volume) to contract against since it’s being moved into the aorta

Question 13

Why does the atrial pressure have a steady increase during ventricular systole

Answer 13

Passive filling of blood from venous system filling up atria and causing an increase in pressure bc AV valves are closed

Question 14

The movement of calcium back out of the cell during ventricular relaxation (phase 3, repol) causes what

Answer 14

A release of Ca from the troponin C and relaxation of myosin

Calcium moves out of the cell via Na-Ca exchanger

Question 15

During diastole, what chamber has a higher pressure

What about during systole

Answer 15

Atria

Ventricles

Question 16

Why does aortic pressure decrease throughout atrial contraction and a little bit into ventricular contraction

Answer 16

Peripheral run-off

Blood flow directed to periphery

Question 17

What has to happen for AV valves to open and what does this mean

Answer 17

Atrial pressure has to increase over the pressure of the ventricles

This means that only slight pressure from the contracting atria will open the AV valves and cause ventricular filling

Question 18

What has to happen for the AV valves to close and the SLV to open in ventricular systole.

Answer 18

Pressure in ventricles must exceed that of the atria - to close the AV valves, and must also exceed the pressure of the Ao and PT respectively to open SLV

Question 19

The period time when the ventricular volume in constant but ventricular pressure is increasing is called what? What is happening with the valves during this stage? When is this represented on the EKG

Answer 19

Called isovolumentric contraction

Ventricular pressure is increasing but has not overcome Ao pressure yet to open SLV

SLV and AV valves are closed

This is represented during the QRS complex

Question 20

Describe how HTN would affect the flow of blood through the Ao.

Answer 20

HTN means higher diastolic pressure which will cause the LV to contract harder (increasing pressure) to overcome Ao pressure and open SLV to send blood to the body.

This will cause LVH

Question 21

When the pressure in the ventricle drops below the arterial pressure, what happens

Answer 21

The AoSLV and PSLV close

Question 22

Define the Dicrotic Notch

Answer 22

The closing of the AoSLV produces the notch in the AO pressure wave. This is peripheral divergence of blood from the Ao, while no more blood i entering the ventricles.

This notch begins the isovolumetric relaxation period

Question 23

Define the isovolumetric relaxation period

Answer 23

No blood entering or leaving ventricles. All valves closed and ventricles are not contracting.

The period ends when the AV valves open (due to passive blood flow into the atria which also causes an increases in pressure and thus the AV valves to open) and blood begins to fill the ventricles

Question 24

Why does blood rapidly fill the ventricles

Answer 24

The pressure and volume are so low compared to the atria, this causes a rapid passive filling

Question 25

Why does Ao pressure continue to drop during diastole

Answer 25

Peripheral run-off

Question 26

What does the A wave in the Jugular Pressure indicate

Answer 26

This is the pressure wave created by the atrial contraction. It is reflected backward since there is no valve between the atria and the great veins

Question 27

Define the C wave

Answer 27

The pressure wave in the Jugular pressure created by the period of isovolumetric contraction (AV and SLV closed) from bulging back into the atrial wall from ventricular contraction

Question 28

When does the C wave end

Answer 28

When the AoSLV opens

Question 29

Define the V wave

Answer 29

The pressure wave of the jugular wave that is created as blood returns back to the heart but can’t enter the ventricles yet (atrial filling and increase in atrial pressure)

Question 30

The QRS complex begins when in regards to ventricular pressure

Answer 30

Just before ventricular pressure begins to rise, but ventricular pressure is constant (isovolumetric contraction)

Question 31

Ventricular pressure starts to decline when in regards to the EKG

Answer 31

The beginning of the T-wave

Question 32

What is the lub (S1) caused by and what does this mean physiologically

Answer 32

The result of blood in the atria hitting the closed valves as it tries to enter the ventricles This means that the ventricles have already begun to contract and have increased their pressure to close the AV valves The LUB is characteristic with atrial contraction.

Question 33

What does the DUB (S2) come from and what does this mean physiologically

Answer 33

Produced from the back flow of blood onto the SLV This means the ventricles have stopped contracting and thus the pressure in the Ao and Pt are now greater than that of the ventricles and have closed the SLV. This sound is associated with ventricular contraction

Question 34

Define stenosis and incompetence

Answer 34

Stenosis - valve doesn’t open fully - causes an increase in the chamber (LVH) Insufficiency - valve does not close fully causing a back flow of blood into the chamber

Question 35

What are the two thing that can cause a murmur in ventricular systole

Answer 35

Mitral valve regurgitation - blood moving back into the atria (insufficiency/incompetence) Ao/PT stenosis - blood not moving out of ventricles well.

Question 36

What can cause a murmur in ventricular diastole

Answer 36

Ao regurgitation - blood moving back into the Ao AV Stenosis - blood cant get into ventricles