The Heart and Blood Vessels (the stages of heartbeat/cardiac cycle)

Question 1

How many stages does the cardiac cycle occur in?

Answer 1

It is occurs in three stages

Question 2

Describe the first stage of the cardiac cycle in detail.

There are four main points

Answer 2

Blood enters the heart.
The atria and ventricles are both relaxed/diastole
Blood enters the atria
All valves are closed

Question 3

Describe the second stage of the cardiac cycle in detail?

There are six main points

Answer 3

1. Blood is pumped from the atria to the ventricles
2. Electrical impulses from the pacemaker cause the atria to contract (atrial systole)
3. Blood is pumped to the ventricles
4. The tricuspid and bicuspid valves open
5. The vena cava and pulmonary veins close to stop blood entering the atria
6. The semilunar valves remain closed

Question 4

Describe the third stage of the cardiac cycle in detail?

There are nine main points

Answer 4

Blood leaves the heart:

1. The atria relax
2. Impulses from the AV node cause the ventricles to contract (ventricular systole)
3. Blood is forced out of the heart into the pulmonary artery and the aorta
4. The pressure forces the semilunar valves to open
5. The pressure closes the tricuspid and bicuspid valves
6. The ventricles now relax again
7. The semilunar valves close, which prevents blood from flowing back into the heart
8. The vena cava and pulmonary veins open and the cycle starts again

Question 5

What is diastole?

Answer 5

Diastole is when the heart chambers relax

Question 6

What is it called when the heart chambers relax?

Answer 6

Diastole

Question 7

What is systole?

Answer 7

Systole is when the chambers of the heart contract

Question 8

What is it called when the chambers of the heart contract?

Answer 8

Systole

Question 9

In the first stage of the cardiac cycle, what chambers of the heart are relaxed?

Answer 9

The atria and ventricles

Question 10

In what stage of the cardiac cycle are all chambers of the heart relaxed?

Answer 10

The first stage

Question 11

In what stage of the cardiac cycle are all the valves of the heart closed?

Answer 11

The first

Question 12

In the second stage of cardiac cycle where is blood pumped to and from?

Answer 12

From the atria to the ventricles

Question 13

In the second stage of the cardiac cycle, what causes the atria to contract?

Answer 13

The impulses from the pacemaker

Question 14

In the second stage of the cardiac cycle, what valves open and which stay closed?

Answer 14

The tricuspid and bicuspid valves open and the semilunar valves remain closed

Question 15

In what stage of the cardiac cycle does the tricuspid and the bicuspid valves open but the semilunar valves remain closed?

Answer 15

The second stage

Question 16

In the second stage of the cardiac cycle, what veins close?

Answer 16

The vena cava and the pulmonary veins

Question 17

In what stage of the cardiac cycle does the vena cava and the pulmonary vein close?

Answer 17

The second stage

Question 18

In the second stage of the cardiac cycle, why do the vena cava and the pulmonary vein close?

Answer 18

To stop blood entering the atria

Question 19

In what stage of the cardiac cycle does just the atria relax and not the ventricles?

Answer 19

The third stage

Question 20

In the third stage of the cardiac cycle, what chambers of the heart contract and which relax

Answer 20

The atria relax while the ventricles contract

Question 21

In the third stage of the cardiac cycle, what causes the ventricles to contract?

Answer 21

The impulses of the AV node