Lecture 7

Question 1

With valves closed, pressure develops during?

Answer 1

Myocardial Contraction

Question 2

When ventricular chamber pressure exceeds aortic blood pressure?

Answer 2

Valves open

Question 3

Blood moves according to?

Answer 3

Pressure gradient (because valves)

Question 4

Open Valve?

Answer 4

Ejection

Question 5

Closed Valve?

Answer 5

Filling

Question 6

(Cardiac Cycle)
Pressure Changes?

Answer 6

(Left)
-Atria
-Ventricle
-Aorta

Question 7

(Cardiac Cycle)
Volume Changes?

Answer 7

Ventricle

Question 8

(Cardiac Cycle)
Electrical Changes?

Answer 8

-Atria
-Ventricle

Question 9

(Cardiac Cycle)
Valve Opening/Closing?

Answer 9

-Aortic Valve (and Pulmonary)
-AV valves (tricuspid/mitral)

Question 10

Phonocardiogram?

Answer 10

Measuring audible sound

Question 11

(Cardiac Cycle)
7 Phases?

Answer 11

1) Atrial systole
2) Ventricular isovolumetric contraction
3) Rapid ventricular ejection
4) Slow ventricular ejection
5) Ventricular isovolumetric relaxation
6) Ventricular filling
7) Diastasis

Question 12

Phase 1?

Answer 12

Atrial Systole

Question 13

Phase 2?

Answer 13

Ventricular isovolumetric contraction

Question 14

Phase 3?

Answer 14

Rapid ventricular ejection

Question 15

Phase 4?

Answer 15

Slow ventricular ejection

Question 16

Phase 5?

Answer 16

Ventricular isovolumetric relaxation

Question 17

Phase 6?

Answer 17

Ventricular filling

Question 18

Phase 7?

Answer 18

Diastasis

Question 19

Phase 1 (Atrial Systole)?

Answer 19

(Depolarization)
-P-wave (Atrial depolarization precedes and triggers atrial contraction)
-“a”-wave (developed atrial pressure)
-Blood moves from atrial chamber and further fills ventricle (increased pressure)
((Mitral) AV valves close: Causes 1st heart sound, Ends phase 1)

Question 20

Phase 2 (Isovolumic Contraction)?

Answer 20

(No change in blood volume in chambers)
-QRS-wave (Ventricular depolarization precedes and triggers rapid ventricular contraction)
-Contraction causes a rapid rise in developed ventricular pressure
-With both input (A-V) and output (aortic) valves closed, no blood moves
(Aortic valve opens: Ending Phase 2)

Question 21

Phase 3 (Rapid Ejection)?

Answer 21

-With ventricular pressure greater than aortic pressure, the aortic valve opens and blood is rapidly ejected from ventricle into aorta, producing a rise in “systolic” aortic pressure
-Ventricular contraction is transmitted mechanically to atria producing “c-wave” in atrial pressure
-T-wave: Ventricular repolarization initiates ventricular relaxation and ends Phase 3

Question 22

Phase 4 (Reduced Ejection)?

Answer 22

-Ventricular relaxation causes a decrease in ventricular pressure
-Ventricle slowly empties
-Continuous return of venous blood begins atrial filling and increased atrial pressure
-Aortic Valve Closes: causes 2nd Heart Sound Ending Phase 4 (all covered due to sound)

Question 23

Phase 5 (Isovolumic Relaxation)?

Answer 23

-Ventricular relaxation (and empty ventricular chamber) causes a rapid drop in ventricular pressure
-Both input (A-V) and output (aortic) valves are closed, no ventricular blood moves
-A-V Valve Opens: Ending Phase 5

Question 24

Phase 6 (Ventricular Filling (Rapid Flow))?

Answer 24

-Ventricular pressure is below atrial pressure, so with the opening of A-V Valve, atrial blood rapidly flows into ventricle (turbulent sound)
-3rd Heart sound is caused by rapid turbulent flow (NOT due to any valves) (louder if ventricle decreases compliance)

Question 25

Phase 7 (Diastasis)?

Answer 25

-A-V Valve is open, and venous blood is slowly filling both the atrial and ventricular chambers -Decreased, slow ventricular filling -Aortic pressure slowly declines as aortic blood is distributed to peripheral tissues -Atrial contraction (systole) ends Phase 7

Question 26

Heart mechanically operates within limits of P-V relations established by?

Answer 26

Passive and Active properties of myocardial tissue

Question 27

EDV - ESV = ?

Answer 27

SV (Stroke Volume)

Question 28

Increase Length = Increase Volume = ?

Answer 28

Increase Preload

Question 29

Increased active force due to greater?

Answer 29

Cross-Bridge Overlap

Question 30

Preload uses what ventricle and measures what?

Answer 30

-End Diastolic Volume -Right atrial pressure, left ventricle and diastolic pressure, pulmonary capillary wedge

Question 31

Afterload uses what ventricle and measures what?

Answer 31

-Aortic pressure -Mean arterial pressure

Question 32

(Length-Tension (Frank-Starling) Relationship) 4 --> 1?

Answer 32

-Increasing length by stretching increases "passive" force -Corresponds to Preload, and degree of stretch "sets" the level of cross-bridge overlap that will affect contractility (Elastic rubber band with little cross-bridge cycling)

Question 33

(Length-Tension (Frank-Starling) Relationship) 1 --> 2?

Answer 33

-Contraction - "Active" isometric force produced by cross-bridge cycling -Chamber pressures increase with contractility (Cross-Bridge cycling + [Ca2+] increases pressure)

Question 34

(Length-Tension (Frank-Starling) Relationship) 2 --> 3?

Answer 34

-Active force overcomes "afterload", allowing muscle shortening with continued cross-bridge cycling and contractility -For the Heart, ventricular pressure exceeds aortic pressure (afterload), allowing ejection (Does not reach max because aortic valve opens)

Question 35

(Length-Tension (Frank-Starling) Relationship) 3 --> 4?

Answer 35

-Active force ends (relaxation) and only "passive" force on shortened muscle remains (Relaxation = only passive forces)