21 Cardiac muscle heart as a pump

Question 1

Muscle tissue that contains intercalated discs

Answer 1

Cardiac muscle (found in myocardium)

Question 2

A single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei. Found in cardiac muscle

Answer 2

Syncytium

Question 3

Ventricular muscle contraction. Stimulated by an action potential

Answer 3

Systole

Question 4

Ventricular muscle relaxation. Na+/K+/Ca++ gradients are reestablished

Answer 4

Diastole

Question 5

aka the atrial wave. Corresponds to atrial depolarization

Answer 5

P wave

Question 6

This complex indicates ventricular depolarization, which triggers contraction of the ventricles

Answer 6

QRS complex

Question 7

Represents the repolarization of the ventricles

Answer 7

T wave

Question 8

The last phase of diastole.Atrial contraction pumps the remaining 10% of blood into the ventricles in this phase.
AV valves open
Aortic & pulmonic valves close
The S4 heart sound occurs

Answer 8

(Phase 1) Atrial contraction

Question 9

The first phase of systole. Contraction of the ventricles occurs with no corresponding volume changing.
AV and semilunar valves are closed
S1 sound occurs
End diastolic volume is found in LV
C wave occurs

Answer 9

(Phase 2) Isovolumetric contraction

Question 10

The blood contained in the ventricles is ejected into the aorta (and lungs in the right heart).
Aortic pressure spikes
Ventricular pressure spikes
V wave occurs
Ventricular volume decreases significantly
Semilunar valves are open, AV valves are closed

Answer 10

(Phase 3) Rapid Ejection

Question 11

Blood continues to leave the ventricles (however, less forcefully).
Decrease in aortic pressure
V wave
End systolic volume is reached
T wave occurs

Answer 11

(Phase 4) Reduced Ejection

Question 12

First phase of diastole.
End systolic volume remains in LV
Aortic pressure: dicrotic notch aka incisural
Ventricular pressure: decreases dramatically
Atrial pressure: Increases steadily
S2 sound occurs
All valves are closed

Answer 12

(Phase 5) Isovolumetric relaxation

Question 13

Av valves open during this phase.
Aortic pressure: decreases
Ventricular pressure: no change
Atrial pressure: decreases slightly
Ventricular volume: increases
S3 sound occurs
V wave ends

Answer 13

(phase 6) Rapid filling

Question 14

Slow, passive ventricular filling.
Ventricular pressure: remains constant
Atrial pressure: remains constant
Ventricular volume: increases steadily (to approach 110 mmHg or ~90% full)
Aortic pressure: Decreases to approx 80 mmHg
AV valves remain open

Answer 14

(phase 7) Reduced filling

Question 15

Make an equation sheet

Answer 15

Do it

Question 16

1) Pressure during filling of the ventricle. 2) Stress in the wall of the left ventricle at the end of diastole.3) The end diastolic pressure when the ventricle has become filled

Answer 16

Preload

Question 17

1) pressure in the aorta leading from the ventricle. 2) Stress in the wall of the left ventricle during ejection

Answer 17

Afterload

Question 18

An increase in EDV (end diastolic volume) leads to an increase in stroke volume

Answer 18

Frank-Starling mechanism

Question 19

T/F. Excess serum K+ concentration increases cardiac contractility by increasing resting membrane potential & the intensity of the action potential

Answer 19

False. Excess K+ decreases contractility by decreasing resting membrane potential & intensity of the action potential

Question 20

T/F. Excess serum Ca++ causes spastic contraction

Answer 20

True

Question 21

T/F. Low serum Ca++ causes cardiac dilation (flaccidity)

Answer 21

True

Question 22

Sound present with reduced ventricular compliance (ventricular hypertrophy)

Answer 22

S4

Question 23

T/F. Blood is always entering the left atrium from the lungs

Answer 23

True