[PhysioEX Chapter 5 exercise 1] PEX-05-01

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Exercise 5: Cardiovascular Dynamics: Activity 1: Studying the Effect of Blood Vessel Radius on Blood Flow Rate Lab Report

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

1. Blood flow is measured in
   You correctly answered: b. ml/min.
2. Which of the following has the greatest effect on blood flow?
   You correctly answered: a. blood vessel radius
3. Which of the following would not result in a decrease in the blood vessel radius?
   You correctly answered: c. vasodilation
4. The diameter of the blood vessel is the same as
   You correctly answered: b. two times the radius of the blood vessel.
5. The opening of the blood vessel where the blood flows is called the
   You correctly answered: b. lumen.

Experiment Results

Predict Question:
Predict Question 1: What do you think will happen to the flow rate if the radius is increased by 0.5 mm?
Your answer : b. The flow rate will increase.
Predict Question 2: Do you think a graph plotted with radius on the X-axis and flow rate on the Y-axis will be linear (a
straight line)?
Your answer : b. no

Stop & Think Questions:
What is the driving force for blood flow?
You correctly answered: b. pressure gradient
How does the body increase the blood vessel radius?
You correctly answered: c. smooth muscle relaxation

Experiment Data:
Flow (ml/min) Radius (mm) Viscosity Length (mm) Pressure (mm Hg)
4.0 1.5 1.0 50 100
12.6 2.0 1.0 50 100
30.7 2.5 1.0 50 100
63.6 3.0 1.0 50 100
117.8 3.5 1.0 50 100
201.0 4.0 1.0 50 100
321.9 4.5 1.0 50 100
490.6 5.0 1.0 50 100

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

1. The variable that you altered in this activity was
   You correctly answered: c. vessel radius.
2. Vessel radius and fluid flow
   You correctly answered: b. are directly proportional.
3. After a heavy meal, when we are relatively inactive, we might expect blood vessels in the skeletal muscles to be
   somewhat __________ and the blood vessels in the digestive organs to be somewhat __________.
   You correctly answered: d. constricted, dilated
4. When you increased the flow tube radius, the fluid flow rate
   You correctly answered: a. increased.

Review Sheet Results

1. Explain how the body establishes a pressure gradient for fluid flow.
   Your answer:
   By heart constraction, the pressure gradient is established.
2. Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your
   prediction?
   Your answer:
   The flow tube radius incresed the flow rate, as I predicted.
3. Describe the effect that radius changes have on the laminar flow of a fluid.
   Your answer:
   When radius incresed, flow of a fluid get more free to flow than when radius is lower.
   The other way, when radius is narrow the flow of a fluid is restricted that rate is low.
4. Why do you think the plot was not linear? (Hint: look at the relationship of the variables in the equation). How well did the
   results compare with your prediction?
   Your answer:
   In graph, line is not stright, because radius and flow rate have not just simple proportion. Flow rate have proportion with the
   fourth power of radius.