Date: 17 June 2012
Title of Lab: Lab Report 2 Physio Ex Lab Exercise 5 Cardiovascular Dynamics Learning Objectives: Activities 1-4
* To understand how blood vessel radius affects blood flow rate. * To understand how vessel radius is changed in the body. * To understand how to interpret a graph of blood Bessel radius versus blood flow rate. * To understand how blood viscosity affects blood flow rate. * To list the components in the blood that contribute to blood viscosity. * To explain conditions that might lead to viscosity changes in the blood. * To understand how to interpret a graph of viscosity versus blood flow. * To understand how blood vessel length affects blood flow rate. * To explain conditions that can lead to blood vessel length changes in the body. * To compare the effect of blood vessel length changes with the effect of blood vessel radius changes on blood flow rate. * To understand how blood pressure affects blood flow rate. * To understand what structure produces blood pressure in the human body. * To compare the plot generated for pressure versus blood flow to those generated for radius, viscosity, and length.
* Activity 1 Effect of Blood Vessel Radius on Blood Flow Rate 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|
* Activity Questions
1. Describe the relationship between vessel radius and blood flow rate? Vessel radius has a direct relationship with blood flow. As blood vessels constrict (vasoconstriction), blood flow is decreased. As blood vessels dilate (vasodilatation), blood flow is increased. 2. In this activity you altered the radius of the flow tube by clicking + and – buttons. Explain how and why the radius of blood vessels is altered in the human body. Contraction or relaxation of smooth muscle of the blood vessel results in a decrease or increase in the blood vessel radius. Different organs have different requirements for blood. 3. Describe the appearance of your plot of blood vessel radius versus blood flow rate and relate the plot to the relationship between these two variables. The points on the plot start at 0 (radius) and increase to 500 (flow) as the radius increases. 4. Describe an advantage of slower blood velocity in some areas of the body, for example, in the capillaries of our fingers. Allows for more time for gas exchange * Review Sheet Results
1. Explain how the body establishes a pressure gradient for fluid flow. The body establishes a pressure gradient for fluid flow due to the pressure difference between the two ends of the vessel. 2. Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your prediction? The flow tube radius change allowed for faster flow. I predicted the flow would be faster. 3. Describe the effect that radius changes have on the laminar flow of a fluid. In a fully constricted vessel, proportionately more blood in contact with the vessel wall and there is less laminar flow, significantly impeding the rate of blood flow in the fully constricted vessel relative to that in the fully dilated vessel. 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? The plot was not linear because the radius was increasing allowing the blood to flow faster. I predicted that it wouldn’t be linear.
* Activity 2 Effect of Blood Viscosity on Blood Flow Rate Flow (ml/min)| Radius (mm)| Viscosity| Length (mm)| Pressure (mm Hg)| 490.6| 5.0| 1.0| 50| 100|
245.3| 5.0| 2.0| 50| 100|