Heart Contractions

The emptying of the atria is controlled by the:

• SA node
• AV node
• Purkinje fibres
• Bundle of His

The pacemaker of the heart is also known as the....

• AV node
• SA node
• Purkinje fibres
• Bundle of His

What fibres allow the ventricles to contract?

• SA
• AV
• Purkinje
• Bundle of His

During the systole phase of the cardiac cycle, the ventricles....

• Contract
• Relax

The heart muscle that these electrical signals control is known as the myocardium

• True
• False

Which letter/s of the ECG shows the ventricles contracting.....

• P
• QRS
• ST

Tags

NGSS.HS-PS2-5

Which node delays the ventricles from firing before fully filled?

• AV
• SA

What is the definition of the Cardiac Cycle?

• the contraction of the atria
• the sequence of events that occur during one complete heartbeat
• the contraction and relaxation of the ventricles
• the circulation of blood in the heart

During ventricular ejection

• only the AV valves open
• the semilunar valves open and the AV valves close
• only the semilunar valves close
• the semilunar valves close and the AV valves open

The semilunar valves are only open during which phase

• atrial contraction and ventricular filling
• isovolumetric contraction
• ventricular ejection
• isovolumetric relaxation