Question

blood flow through the heart

• blood enters the _ atrium.
• moves to the _ ventricle.
• travels to the _.
• returns to the _ atrium.
• moves to the _ ventricle
• pumped out to the _.

the heartbeat

• the sound “lub - dub” comes from _ closing.
• the heart’s natural pacemaker is called the _ node.
• average heart rate: _ beats per minute.

Explanation:

• For the blood flow through the heart:
• Deoxygenated blood first enters the right atrium.
• Then moves to the right ventricle.
• Is pumped to the lungs (for oxygenation).
• Oxygenated blood returns to the left atrium.
• Moves to the left ventricle.
• Is pumped out to the body.
• For the heartbeat:
• The "lub - dub" sound is from heart valves (atrioventricular and semilunar valves) closing.
• The sino - atrial node is the heart's natural pacemaker.
• The average heart rate for a healthy adult is 60 - 100 beats per minute.

Answer:

• Blood Flow Through the Heart: right, right, lungs, left, left, body
• The Heartbeat: heart valves, sino - atrial, 60 - 100