Mechanical activity of the heart

Question 1

Mechanical activity of the heart

Systole

Answer 1

Contraction

Question 2

Mechanical activity of the heart

Diastole

Answer 2

Relaxation

Question 3

Mechanical activity of the heart

5 stages of the cardiac cycle

(VD - ventricular diastole, VS - ventricular systole)

Answer 3

1. Active ventricular filling (VD)
2. Isovolumetric contraction (VS)
3. Ejection phase (VS)
4. Isovolumetric relaxation (VD)
5. Passive ventricular filling (VD)

Question 4

Mechanical activity of the heart

Active ventricular filling of the cardiac cycle

Answer 4

Atrial systole, ventricular diastole

Ventricles already about 70% full

Left and right atria contract to force blood into ventricles

Question 5

Mechanical activity of the heart

Isovolumetric contraction of the cardiac cycle

Answer 5

First phase of ventricular systole

Contraction of ventricles close AV valves

Pressure in ventricles increase until greater than arterial pressure

Semi-lunar valves open

Question 6

Mechanical activity of the heart

Ejection phase of the cardiac cycle

Answer 6

Ventricular pressure is greater than aterial pressure

Semi-lunar valves open and blood ejected

Ventrical pressure falls and blood pressure in arteries causes the semi-lunar valves to close

Question 7

Mechanical activity of the heart

Isovolumetric relaxation

Answer 7

Short peroid of ventricular relaxation after semi-lunar valves close

When ventricle pressure falls below atrial pressure AV valves open

Question 8

Mechanical activity of the heart

End systolic volume is what?

Answer 8

The volume of blood left in the ventricle after ejection

Question 9

Mechanical activity of the heart

Passive ventricular filling

Answer 9

Both the atria and ventricles are relaxed

AV valves are open and ventricles fill passively from the atria

Question 10

Mechanical activity of the heart

What causes the semi-lunar valves to open?

Answer 10

When the pressure of the ventricles is greater than that of the arteries

Question 11

Mechanical activity of the heart

Is active ventricular fillling vetricular diastole or systole?

Answer 11

Diastole

Question 12

Mechanical activity of the heart

Is isovolumetric contraction vetricular diastole or systole?

Answer 12

Systole

Question 13

Mechanical activity of the heart

Is the ejection phase vetricular diastole or systole?

Answer 13

Systole

Question 14

Mechanical activity of the heart

Is isovolumetric relaxation vetricular diastole or systole?

Answer 14

Diastole

Question 15

Mechanical activity of the heart

Is passive ventricular filling vetricular diastole or systole?

Answer 15

Diastole

Question 16

Mechanical activity of the heart

What affect does an increased heart rate have on the cardiac cycle?

Answer 16

All phases become shorter, especially time spent in diastole

Less time filling the ventricles so less blood to be pumped

Question 17

Mechanical activity of the heart

What are the heart sounds caused by?

Answer 17

The closing of the valves

Question 18

Mechanical activity of the heart

Heart murmours before or after heart sounds indicates what?

Answer 18

Valve problems