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| 1 | |
Look at your graph. What was the effect of stretching (from 11 mm) on the amount of tension produced by the contracting heart? |
| | A) | the amount of tension increased to a maximum value and then decreased. |
| | B) | the amount of tension increased. |
| | C) | the amount of tension decreased to a minimum value and then increased. |
| | D) | the amount of tension did not change. |
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| 2 | |
Look at your graph. At what length was maximum tension recorded from the heart? |
| | A) | 11 mm |
| | B) | 13 mm. |
| | C) | 15 mm. |
| | D) | 17 mm. |
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| 3 | |
At heart lengths less than 15 mm, the amount of thick and thin filament overlap was: |
| | A) | greater than that at 15 mm. |
| | B) | the same as that at 15 mm. |
| | C) | less than that at 15 mm. |
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| 4 | |
Assume that the amount of blood passing around the circulatory system increases. If the heart rate remains constant, then the amount of blood returning to the heart would: |
| | A) | increase |
| | B) | remain constant. |
| | C) | decrease. |
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| 5 | |
Increasing the amount of blood returning to the heart would: |
| | A) | decrease the end diastolic volume. |
| | B) | increase the end diastolic volume. |
| | C) | not change the end diastolic volume. |
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| 6 | |
What happens to the length of the muscle fibers if the end diastolic volume is increased? |
| | A) | The muscle fibers will shorten. |
| | B) | The muscle fibers will stay the same length. |
| | C) | The muscle fibers will lengthen. |
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| 7 | |
If stretching increases the amount of tension produced by the heart, what would be the effect of such a stronger contraction on the stroke volume, the amount of blood ejected by the contraction? |
| | A) | Increase stroke volume. |
| | B) | Decrease stroke volume. |
| | C) | Have no effect on stroke volume. |
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| 8 | |
According to your graph, what happens to the amount of tension produced by the heart if it is stretched beyond 15 mm? |
| | A) | The amount of tension increases. |
| | B) | The amount of tension remains constant. |
| | C) | The amount of tension decreases. |
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| 9 | |
When compared with the situation at a heart length of 15 mm, if the amount of venous blood returning to the heart increases so that the length of the heart increases to 17 mm: |
| | A) | the end diastolic volume would be greater, but the stroke volume would be less. |
| | B) | the end diastolic volume would be greater, and the stroke volume would also be greater. |
| | C) | the end diastolic volume would be smaller, but the stroke volume would be greater. |
| | D) | the end diastolic volume would be smaller, and the stroke volume would also be smaller. |
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| 10 | |
What strategies are used by the cardiovascular system to insure that cardiac muscles are not over stretched by an increase in the amount of venous blood returning to the heart? |
| | A) | Cardiac fibers have limited compliance, so they do not overstretch. |
| | B) | The heart rate increases and the end diastolic volume remains within reasonable limits. |
| | C) | The atria restrict blood flow and prevent ventricle expansion. |
| | D) | The veins contract to restrict blood flow back to the heart. |
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