Cardiac Cycle

Question 1

7 Periods of the cardiac cylcle

Answer 1

Period 1 – atrial systole
Only period which atria are contracted
Period 2 – isovolumic contraction
Period 3 – rapid ejection
Period 4 – reduced ejection
Period 5 – isovolumic relaxation
Period 6 – rapid ventricular filling
Period 7 – reduced ventricular filling

Question 2

PERIOD 1

Answer 2

Atrial systole
Atria are contracted
Ventricles are relaxed
AV open A&P closed

Question 3

PERIOD 2

Answer 3

Isovolumic contraction
Ventricle contract w/ NO change in volume
Atria are relaxing
AV closed A&P closed

Question 4

PERIOD 3

Answer 4

Rapid Ejection
Ventricles are contracting
Atria are relaxed
AV closed A&P open

Question 5

PERIOD 4

Answer 5

Reduce Ejection
Ventricles still contracting
atria still relaxed
AV closed A&P open

Question 6

PERIOD 5

Answer 6

Isovolumic relaxation
Ventricles relaxing NO change in volume
Atria relaxed
AV closed A&P closed

Question 7

PERIOD 6

Answer 7

Rapid ventricular filling
Ventricles relaxed
Atria not contracting to fill ventricles sucking
AV open & A&P closed

Question 8

PERIOD 7

Answer 8

Reduced ventricular filling
Ventricles relaxed
Atria relaxed positive pressure
AV open A&P closed

Question 9

A wave

Answer 9

Increase in atrial pressure accompanying the decrease in size of the atrial cavity and forced expulsion of blood into the ventricle

Question 10

C wave

Answer 10

Increase in atrial pressure during isovolumic contraction
From ventricular contraction
AV valves close as ventricles depolarize
Depolarization begins at interventricular septum  result is heart is temporarily shortened
Shortening forces AV valves into atria  increase in atrial pressure
Subsequent contraction of the rest of ventricular myocardium results in the heart lengthening  AV valves “pulled out” of atria and pressure decreases

Question 11

V wave

Answer 11

Pressure increase in atria associated w/ venous return.
Occurs during isovolumic relaxation of ventricle
At end, AV valves open and rapid filling of ventricle begins so decrease in atrial pressure

Question 12

P wave physical

Answer 12

period 1 of cc atrial systole

Question 13

QRS complex physical

Answer 13

isovolumic contraction of ventricle

Question 14

ST interval physical

Answer 14

rapid ejection phase: the ventricle is still contraction to expel blood

Question 15

T wave physical

Answer 15

reduced ejection as the ventricle begins to relas & pressure decreases

Question 16

Calculate the stroke volume from the left ventricular end diastolic volume (LVEDV) and left ventricular end systolic volume (LVESV)

Answer 16

Stroke volume is the diff btw LVEDV and LVESV

it represents the volume of blood discharged into circulation w/ each cycle

Question 17

S1

Answer 17

S1 - closing of the mitral and tricuspid valves at the beginning of isovolumic contraction, LUB

Question 18

S2

Answer 18

S2 closing of the aortic and pulmonic valves at end of cardiac cycle DUB

Question 19

S3

Answer 19

S3 - occurs at the transition btw rapid ventricular filling and reduced ventricular feeling. Sudden tensing of the chordae tendinae. EARLY DIASTOLIC sound
pressure is increasing

Question 20

S4

Answer 20

S4 - an abnormal noise made in the ventricles after the peak of the A wave as ventricular stenosis at the beginning of ventricular filling

Question 21

S5

Answer 21

Opening snap (abnormal) heard in cases of mitral

Question 22

Diastolic murmurs

Answer 22

occur after S2, but before the next S1.
Ventricles relax
Common mitral valve stenosis

Question 23

Systolic murmurs

Answer 23

After S1 before S2
S2 marks the beginning of ventricular relaxation
Common in mitral valve regurgitation

Question 24

Splitting mechanism 1

Answer 24

Inhalation results in expansion of the pulmonary artery, this leads to more flow through the artery
This effect increases the time that blood flows through the pulmonary valve
The result is a delayed closing of the pulmonary valve

Question 25

Spitting mechanism 2

Answer 25

With inhalation, the favorable pressure gradient (more negative) increases venous return
The result of this is the RVEDV will be increased compared to exhalation
More time is required to empty the right ventricle
End result is pulmonary valve remains open longer

Question 26

Splitting mechanism 3

Answer 26

With inhalation, a small amount of blood is trapped in the lungs, this is because as the lungs expand, so do the vessels in the lungs, this decreases venous return to the left side of the heart
This results in less blood being expelled from the left ventricle
Because less blood is expelled, the aortic valve closes sooner

Question 27

Normal splitting

Answer 27

AV closes before PV

Question 28

L bundle branch block & severe hypertensions

Answer 28

Increases the time of depolarization of the L ventricle
Impulse not traveling through fast Pfibers but the gap junctions.
R ventricle normal.
Heard on exhalation