AS Biology How to calculate the mean volume of blood leaving the left ventricle per m

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JVelo
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#1
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#1
Hi I'm really stuck on question 5 from the AS Biology Specimen Paper 2 Set 2. The question contains a picture of an ECG with 8 large spikes and says
an electrocardiogram shows the electrical activity of the heart. figure 6 shows an ECG for an animal of species B at rest. Each large spike represents a contraction of the ventricles. for species B the mean volume of blood leaving the left ventricle during each contraction is 0.03cm.
Calculate the mean volume of blood leaving the left ventricle per minute.
Please help me
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Kvothe the Arcane
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#2
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(Original post by JVelo)
Hi I'm really stuck on question 5 from the AS Biology Specimen Paper 2 Set 2. The question contains a picture of an ECG with 8 large spikes and says
an electrocardiogram shows the electrical activity of the heart. figure 6 shows an ECG for an animal of species B at rest. Each large spike represents a contraction of the ventricles. for species B the mean volume of blood leaving the left ventricle during each contraction is 0.03cm.
Calculate the mean volume of blood leaving the left ventricle per minute.
Please help me
Work out how many contractions there are per minute and multiply that frequency by the mean volume per contraction.
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JVelo
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(Original post by Kvothe the Arcane)
Work out how many contractions there are per minute and multiply that frequency by the mean volume per contraction.
thankssss- i dont mean to sound stupid but how do I work out how many contractions there are in a minute
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Kvothe the Arcane
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(Original post by JVelo)
thankssss- i dont mean to sound stupid but how do I work out how many contractions there are in a minute
I'll use a very related analogy. If you're measuring your pulse rate and there are 8 pulses in 10 seconds or 1.25 seconds per pulse, how many pulses are there in 1 minute?
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JVelo
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(Original post by Kvothe the Arcane)
I'll use a very related analogy. If you're measuring your pulse rate and there are 8 pulses in 10 seconds or 1.25 seconds per pulse, how many pulses are there in 1 minute?
480?
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Kvothe the Arcane
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(Original post by JVelo)
480?
No. Where did you get that from?
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JVelo
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(Original post by Kvothe the Arcane)
No. Where did you get that from?
yeah i think i meant 8x6= 48
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Kvothe the Arcane
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#8
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(Original post by JVelo)
8 x 60
Why do you think it'd be 8 \times 60 ?
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JVelo
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#9
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(Original post by Kvothe the Arcane)
Why do you think it'd be 8 \times 6 ?
8 pulses in 10 seconds so in 60 seconds wouldn't there be 8x6 as 10x6=60 (im really sorry im no good at maths)
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Kvothe the Arcane
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#10
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(Original post by JVelo)
8 pulses in 10 seconds so in 60 seconds wouldn't there be 8x6 as 10x6=60 (im really sorry im no good at maths)
Yup, there'd be 48. Can you now figure out how to do your problem?
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JVelo
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#11
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(Original post by Kvothe the Arcane)
Yup, there'd be 48. Can you now figure out how to do your problem?
yup thanks
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ElyrionEve
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Hey there! Also stuck on this question! I know you probably don't need this now, and I'm not sure if this is right whatsoever, but my idea was to find the amount of milliseconds per minute. which is (60x1000) = 60000 milliseconds per minute. I then looked at the ECG and discovered that per 100 milliseconds, the left ventricle contracts once. So I divided 60000 by 100 to find the amount of contractions per minute (which is 600). Then I multiplied the mean volume per contraction (0.03cm^3) by the amount of contractions a minute (600). To get 18cm^3. How does this sound to you guys? Could be completely wrong, but it's an idea! P.s. If you found out how to do this question, could you verify it to me, too?

-Ely
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shak21
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#13
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#13
Its right, thank you so much !
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