Question

What are the 3 events dies a heart beat consist of. Give the duration of heart beat

Answer 1

Your heartbeat is triggered by electrical impulses that travel down a special pathway through your heart:

1. SA node (sinoatrial node) – known as the heart’s natural pacemaker. The impulse starts in a small bundle of specialized cells located in the right atrium, called the SA node. The electrical activity spreads through the walls of the atria and causes them to contract. This forces blood into the ventricles. The SA node sets the rate and rhythm of your heartbeat. Normal heart rhythm is often called normal sinus rhythm because the SA (sinus) node fires regularly.
2. AV node (atrioventricular node). The AV node is a cluster of cells in the center of the heart between the atria and ventricles, and acts like a gate that slows the electrical signal before it enters the ventricles. This delay gives the atria time to contract before the ventricles do.
3. His-Purkinje Network. This pathway of fibers sends the impulse to the muscular walls of the ventricles and causes them to contract. This forces blood out of the heart to the lungs and body.
4. The SA node fires another impulse and the cycle begins again.

At rest, a normal heart beats around 50 to 99 times a minute. Exercise, emotions, fever and some medications can cause your heart to beat faster, sometimes to well over 100 beats per minute.

How fast does the normal heart beat?

How fast the heart beats depends on the body's need for oxygen-rich blood. At rest, the SA node causes your heart to beat about 50 to 100 times each minute. During activity or excitement, your body needs more oxygen-rich blood; the heart rate rises to well over 100 beats per minute.

Medications and some medical conditions may affect how fast your heart-rate is at rest and with exercise.

Normal Heart Beat

1. The SA node sets the rate and rhythm of your heartbeat.
2. The SA node fires an impulse. The impulse spreads through the walls of the right and left atria, causing them to contract. This forces blood into the ventricles.
3. The impulse travels to the AV node. Here, the impulse slows for a moment before going on to the ventricles.
4. The impulse travels through a pathway of fibers called the HIS-Purkinje network. This network sends the impulse into the ventricles and causes them to contract. This forces blood out of the heart to the lungs and body.
5. The SA node fires another impulse. The cycle begins again.

Answer 2

Answer:

Every single beat of the heart involves three major stages: cardiac diastole, when chambers are relaxed and filling passively; atrial systole when the atria contract leading to ventricular filling; and ventricular systole when blood is ejected into both the pulmonary artery and aorta.