Heart Beat Sound

Question 1

What is the intrinsic control of the heartbeat (SA)?

Answer 1

The intrinsic control of the heartbeat is the sinoatrial node (SA node) which is loacted in the right atrium. It generates an electrical signal that causes the upper heart chambers to contract. SA node is the pacemaker of the heart.

Question 2

What is the extrinsic control of the heartbeat?

Answer 2

The extrinsic control of the heartbeat is the medulla oblongata in the brain. It connects to the heart through two different pathways.

Question 3

What is diastole?

Answer 3

Diastole is when the heart relaxes after contarction.

Question 4

What is systole?

Answer 4

Systole occurs when the heart contracts and pumps blood.

Question 5

What is the intrinsic control of the heartbeat (AV Node)?

Answer 5

The electrical signal from the SA node passes through the Atrioventricular node (AV node) to the lower heart chambers (ventricles) and causes them to contract.

Question 6

What causes systole?

Answer 6

Systole is caused when the heart muscle contract and pushes the blood out of the heart and into the large blood vessels of the circulatory system.

Question 7

What causes diastole?

Answer 7

Diastole is when filling and ventricular relaxation occurs. Diastole is when the blood vessels return blood to the heart in prepartation of the next contraction.

Question 8

What causes the ‘lub dub’ of a healthy heart?

Answer 8

The ‘lub’ spund is caused by the closure of the AV (mitral abd tricuspid valves) when the ventricles relax. The ‘dub’ sound is caused by the closure of the semilunar valves (aortic and pulmonary).

Question 9

How long is an average cardiac cycle?

Answer 9

The cardiac cycle ranges from 0.6-1 second in humans.