The cardiac cycle

Question 1

what is systole and diastole

Answer 1

systole (contraction) and diastole (relaxation).

Question 2

Ventricular systole: major steps

Answer 2

1) Tension in the ventricles closes the cuspidal valves
2)The ventricle continues to increase its tension while all
valves are closed.
3)The increasing tension deforms the heart (spherical shape)

Question 3

Ventricular systole: major steps: 2) The ventricle continues to increase its tension while all
valves are closed. DETAIL

Answer 3

• In this phase the contractile components (CC)
  shorten and stretch the serial elastic elements (SEC).
• There is no volume change, while the tension
  increases: therefore the name of this contraction is
  “isovolumetric contraction”.

Question 4

Ventricular systole: what is Isovolumetric contraction:

Answer 4

When the internal pressure of the ventricles goes just above the pressure found in the aorta and the pulmonary
artery, the semilunar valves open.

Question 5

Ventricular systole: what is Auxotonic contraction

Answer 5

Auxotonic contraction: Blood enters the large
arteries while the tension further increases.

Question 6

Ventricular diastole: includes :

Answer 6

1) Isovolumetric relaxation
2) Isotonic relaxation
3) Atrial systole

Question 7

Ventricular diastole:1) Isovolumetric relaxation

Answer 7

The pressure in the ventricles falls below the pressure of the atria. A passive opening of the cuspidal valves occurs and the filling phase commences.

Question 8

Ventricular diastole: Isotonic relaxation:

Answer 8

Isotonic filling. Lasts for 410 msec.
Can be divided into:
▪ Fast filling: 60% of filling.
▪ Reduced filling: A smaller fraction of blood enters the ventricles. At the end of this phase the SA node generates a new AP: the depolarization and the subsequent contraction of the atria commences

Question 9

Parameters of the cardiac cycle: what are the 5

Answer 9

1) Pressure
2) Volume
3) Valves
4) Heart sounds
5) Jugular pressure

Question 10

Parameters of the cardiac cycle: Pressure

Answer 10

changes of pressure values:
- in the pulmonary veins,
- in the left atrium,
- in the left ventricle,
- and in the aorta
determine the position of the valves and accordingly the flow of blood in these compartments.

Question 11

Parameters of the cardiac cycle: Volume

Answer 11

The volume is constant in the isovolumetric stages of cardiac cycle.
Ejection phase of systole the volume decrease fast then slows down.
During diastole a rapid filling phase is followed by reduced filling

Question 12

Parameters of the cardiac cycle: Valves

Answer 12

Semilunar valves are closed during diastole
Semilunar valves open during systole,
cuspid valves are open during diastole
cuspid valves closed during systole.

Question 13

Parameters of the cardiac cycle: Heart sounds 1st sounds

Answer 13

Isovolumetric contraction
During and just after the closure of the cuspidal
valves (systolic heart sound).

Question 14

Parameters of the cardiac cycle: Heart sounds 2nd sounds

Answer 14

Isovolumetric relaxation
Generating during and just after the closure of the semilunar valves (diastolic heart sound).

Question 15

Parameters of the cardiac cycle: Heart sounds 3rd sounds

Answer 15

Originates from the rapid filling of the ventricle

Question 16

Parameters of the cardiac cycle: Heart sounds 4th sounds

Answer 16

Result of the turbulent flow caused by the atrial
contraction (may lack).

Question 17

Parameters of the cardiac cycle: Jugular pressure

Answer 17

at the beginning of the diastole the heart moves cranially and this increases the pressure in the jugular vein.