Studying the Effect of Stroke Volume on Pump Activity

7/10/2020 PhysioEx Exercise 5 Activity 6 PhysioEx Lab Report Exercise 5: Cardiovascular Dynamics Activity 6: Studying the Effect of Stroke Volume on Pump Activity Name: Date: 10 July 2020 Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1 Which of the following variables directly contributes to preload? You correctly answered: venous return. 2 Which of the following would not increase end diastolic volume? You correctly answered: dehydration. 3 Increased contractility of the heart results in all but which of the following? You correctly answered: increased end systolic volume. 4 Which of the following does not affect stroke volume? You correctly answered: All of these affect stroke volume. 5 Which of the following is not equivalent to the others? You correctly answered: end diastolic volume. Experiment Results Predict Question 1 Predict Question: If the pump rate is analogous to the heart rate, what do you think will happen to the rate when you increase the stroke volume? Your answer: The pump rate will decrease to maintain cardiac output. Stop & Think Questions 1 Why did changing the ending pump volume (ESV) automatically change the stroke volume? You correctly answered: The heart intrinsically alters stroke volume to accommodate changes in preload. 1/3 7/10/2020 PhysioEx Exercise 5 Activity 6 2 The flow has stayed constant with each trial because You correctly answered: cardiac output is equivalent to blood flow. 3 How does the heart provide for an increase in stroke volume? You correctly answered: 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 40 5086.8 3.0 3.0 20 254.3 40 40 5086.8 3.0 3.0 30 169.6 40 40 5086.8 3.0 3.0 40 127.2 40 40 5086.8 3.0 3.0 50 101.7 40 40 5086.8 3.0 3.0 60 84.8 40 40 5086.8 3.0 3.0 80 63.6 40 40 5086.8 3.0 3.0 100 50.9 40 40 Post-lab Quiz Results You 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: Pump rate would increase. Why might an athlete's resting heart rate be lower than that of the average person? 2/3 7/10/2020 PhysioEx Exercise 5 Activity 6 You correctly answered: Stroke volume and contractility have increased. 3 In this activity, which of the following stayed constant? You correctly answered: flow rate. 4 Which of the following is true? You correctly answered: ESV = EDV - SV. Review Sheet Results 1 Describe the Frank-Starling law of the heart. Your answer: When the stretch of the cardiac muscle cell get stronger then the greater the force of contraction. 2 Explain what happened to the pump rate when you increased the stroke volume? Why do you think this occurred? How well did the results compare with your prediction? Your answer: The pump rate decreased to maintain cardiac output as prediction. Stroke volume and pump rate are the factor of cardiac output. 3 Describe how the heart alters stroke volume. Your answer: By changing contractility, heart can alter stroke volume. 4 Describe the intrinsic factors that control stroke volume. Your answer: The contractility can control stroke volume, and preload can control stroke volume as well. The contractility is the force that the muscle create at the given length. The preload gives the volume of blood that the ventricle has available to pump. 3/3