GCSE OCR Biology - Heart Rate

GCSE Biology Revision of Heart Rate

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  • Created by: harry
  • Created on: 12-04-13 12:15
How does does heart rate change during exercise?
Heart rate increases
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Why does this happen?
Because the muscles produce more CO2 when they exercise. The brain detects this change and tells the body to breathe faster and pump more blood to the muscles - causing the increase in heart rate
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What is this known as?
Negative feedback
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What does SAN stand for?
Sino-Atrial node
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What does AVN stand for?
Atrio-Ventricular node
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Describe stage 1 of a complete heart beat
The SAN produces a small electrical current which spreads to the atria, causing them to contract.
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Describe stage 2 of a complete heart beat
The current stimulates the AVN to produce an electrical current which causes the Ventricles to contract
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What does this process ensure?
That the Atria always contract before the Ventricles
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What does ECG stand for?
Electrocardiogram
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What does this show?
The electrical activity of the heart
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In a healthy person's ECG, what is the first, small peak?
The atria contacting
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What is the large peak?
The ventricles contracting
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What is the third small peak?
The ventricles relaxing
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If the peaks are close together what does this show?
Fast heartbeat
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Other cards in this set

Card 2

Front

Why does this happen?

Back

Because the muscles produce more CO2 when they exercise. The brain detects this change and tells the body to breathe faster and pump more blood to the muscles - causing the increase in heart rate

Card 3

Front

What is this known as?

Back

Preview of the front of card 3

Card 4

Front

What does SAN stand for?

Back

Preview of the front of card 4

Card 5

Front

What does AVN stand for?

Back

Preview of the front of card 5
View more cards

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