Exercise 5: Cardiovascular Dynamics: Activity 6: Studying the Effect of Stroke Volume on Pump Activity Lab Report

Pre-lab Quiz ResultsYou scored 100% by answering 5 out of 5 questions correctly.

1. Which of the following variables directly contributes to preload?You correctly answered: b. venous return

2. Which of the following would not increase end diastolic volume?You correctly answered: c. dehydration

3. Increased contractility of the heart results in all but which of the following?You correctly answered: d. increased end systolic volume

4. Which of the following does not affect stroke volume?You correctly answered: d. All of these affect stroke volume.

5. Which of the following is not equivalent to the others?You correctly answered: c. end diastolic volume

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Experiment ResultsPredict Question:Predict Question: If the pump rate is analogous to the heart rate, what do you think will happen to the rate when youincrease the stroke volume?Your answer : b. The pump rate will increase to maintain cardiac output.

Stop & Think Questions:Why did changing the ending pump volume (ESV) automatically change the stroke volume?You correctly answered: d. The heart intrinsically alters stroke volume to accommodate changes in preload.

The flow has stayed constant with each trial becauseYou correctly answered: a. cardiac output is equivalent to blood flow.

How does the heart provide for an increase in stroke volume?You correctly answered: b. by increasing contractility

Experiment Data:

Flow(ml/min)

Rad. L (mm)

Rad. R (mm)

Str. V (ml) Rate(strokes/min)

Press. L (mm Hg)

Press. Dif. R (mm Hg)

5086.8 3.0 3.0 10 508.7 40 405086.8 3.0 3.0 20 254.3 40 405086.8 3.0 3.0 30 169.6 40 405086.8 3.0 3.0 40 127.2 40 405086.8 3.0 3.0 50 101.7 40 405086.8 3.0 3.0 60 84.8 40 405086.8 3.0 3.0 80 63.6 40 405086.8 3.0 3.0 100 50.8 40 40

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Post-lab Quiz ResultsYou scored 100% by answering 4 out of 4 questions correctly.

1. What do you think would happen when stroke volume is decreased?You correctly answered: b. Pump rate would increase.

2. Why might an athlete's resting heart rate be lower than that of the average person?You correctly answered: e. Stroke volume and contractility have increased.

3. In this activity, which of the following stayed constant?You correctly answered: c. flow rate

4. Which of the following is true?You correctly answered: d. ESV = EDV - SV

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Review Sheet Results1. Describe the Frank-Starling law in the heart.Your answer:La ley de Frank-Starling, llamada tambin mecanismo de Frank-Starling,describe la capacidad del corazn de adaptarse avolmenes crecientes de flujo sanguneo. Es decir, si la precarga aumenta, incrementa la fuerza de contraccin y, comoconsecuencia, el volumen sistlico.

2. Explain what happened to the pump rate when you increased the stroke volume? Why do you think this occurred? Howwell did the results compare with your prediction?Your answer:lo que susecio es que a medida que aumenta el volumen de llegada, se necesita ms tiempo para llenar la bomba y lavelocidad de la bomba disminuye. Para mantener el flujo de sangre adecuado a los tejidos, el volumen de llegada debe sermayor si la frecuencia cardaca se reduce.

3. Describe how the heart alters stroke volume.Your answer:El corazon altera el volumen sistlico al cambiar su contractilidad.

4. Describe the intrinsic factors that control stroke volume.Your answer:Los factores intrnsecos que determinan el volumen sistlico son la precarga y la contractilidad. La precarga da el volumende sangre que el ventrculo tiene disponible para bombear, as como la longitud diastlica final del msculo. Lacontractilidad es la fuerza que el msculo puede crear en la longitud dada. Estos factores establecen el volumen de sangrebombeada con cada latido del corazn