PhysioEx Lab Report Exercise 5: Cardiovascular Dynamics Activity 3: Studying the Eﬀect of Blood Vessel Length on Blood Flow Rate Name: Date: 30 March 2021 Pre-lab Quiz Results You scored 75% by answering 3 out of 4 questions correctly. 1 When the length of the blood vessel increases, which of the following also increases? You correctly answered: both friction and surface area. 2 Blood vessel length decreases You correctly answered: when we lose weight. 3 Blood ﬂow is You correctly answered: directly proportional to vessel radius to the fourth power. 4 Which of the following correctly describes resistance to ﬂow? Your answer: Resistance to ﬂow increases with increased vessel radius. Correct answer: Resistance to ﬂow increases with increased vessel length. Experiment Results Predict Question 1 Predict Question: What eﬀect do you think increasing the ﬂow tube length will have on the ﬂuid ﬂow rate? Your answer: The ﬂuid ﬂow rate will decrease. Stop & Think Questions 1 What is the relationship between ﬂuid ﬂow and ﬂow tube length? You correctly answered: They are inversely proportional to each other. 2 Which is more likely to occur on a daily basis? You correctly answered: changes in blood vessel diameter. Experiment Data Flow (ml/min) Radius (mm) Viscosity Length (mm) Pressure (mm Hg) 90.8 3.0 3.5 10 100 60.6 3.0 3.5 15 100 45.4 3.0 3.5 20 100 36.3 3.0 3.5 25 100 30.3 3.0 3.5 30 100 26.0 3.0 3.5 35 100 22.7 3.0 3.5 40 100 Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 Increasing the ﬂow tube length is analogous to increasing blood vessel length. How did this aﬀect the ﬂow rate? You correctly answered: The ﬂow rate decreased. 2 Which of the following correctly describes the relationships between blood vessel length, resistance, and blood ﬂow? You correctly answered: Blood vessel length is directly proportional to resistance and inversely proportional to blood ﬂow. 3 Which of the following correctly describes the relationships between blood vessel radius, resistance, and blood ﬂow? You correctly answered: Blood vessel radius is inversely proportional to resistance and directly proportional to blood ﬂow. 4 Which of the following describes why the body might require an increase in vessel radius? You correctly answered: to provide more blood ﬂow and, therefore, nutrients to a particular body part. Review Sheet Results 1 Which is more likely to occur, a change in blood vessel radius or a change in blood vessel length? Explain why. Your answer: the change in radius can be controlled much faster than the change in length. 2 Explain the eﬀect that the change in blood vessel length had on ﬂow rate. How well did the results compare with your prediction? Your answer: the longer the vessel is is, the longer the ﬂow rate will be. 3 Explain why you think blood vessel radius can have a larger eﬀect on the body than changes in blood vessel length (use the blood ﬂow equation). Your answer: the vessel radius allows for less resitance which will provide better blood ﬂow. 4 Describe the eﬀect that obesity would have on blood ﬂow and why. Your answer: Longer blood vessels due to weight gain will lead to bad blood ﬂow.