Introduction: Provides an overview and links to background information on the lab.
Notebook: Record your own notes on the results of the lab—your hypotheses, details about results, and conclusions. You can also move data from the results pages directly to the Notebook.
Assignments: Doing the assignments is helpful to understanding the concepts of this lab. The Assignments here were written to benefit a wide range of general biology classes and you should find them useful, but check with your instructor before proceeding with any assignments.
Glossary: The glossary contains definitions for selected terms in the lab.
Help: Explanations and hints on using all features of the lab are in Help.
The first screen in CardioLab is the Equation screen which graphically illustrates the equation for Mean Arterial Pressure (MAP). This shows the relationships between the measurements for the variables Resistance (Viscosity and Vessel Radius) and Cardiac Output (Heart Rate and Stroke Volume—Diastolic Ventricle Volume and Systolic Ventricle Volume). When one variable is changed, note how the values for variables higher up in the equation change. Variables changed on this screen will not affect the values of variables in the experiment on the next screen.
Reset Values: After playing with the values on this screen, you can click the Reset Values button to reset all variables to their default values.
To Experiment: Click on the To Experiment button in the lower left corner of the Equation screen to start a Lab experiment.
The Experiment screen allows you to monitor the following values in a simulated subject: Mean Arterial Pressue (MAP), Heart Rate, Stroke Volume, Total Peripheral Resistance, and Blood Volume. The chart at the bottom of the screen will graph these values in real time while you manipulate variables or introduce interventions from the tab-folder at the top of the screen.
Variables: The Variables that can be affected by manually altering them are Heart Rate, Vessel Radius, Viscosity, Blood Volume, Venous Capacity, and Systolic Ventricle Volume.
Check Boxes: Clicking a check box next to a variable will "freeze" that variable so that it remains unaltered by the cardiovascular system's attempts to compensate for changes in other variables.
Interventions: Interventions are conditions or events that affect the normal functioning of the cardiovascular system. You can see a description of each intervention by selecting that intervention on the pull-down menu. You can then click Apply Intervention to see how this intervention affects the different measurements in the system.
The Interventions are Small Hemorrhage, Large Hemorrhage, Treadmill, Dehydration, Distributive Shock, IV Infusion, Epinephrine, and Foxglove.
Cases: The cases represent different simulated subjects with different medical conditions that can affect the cardiovascular system. You can see a description of each case by selecting the case in the pull-down menu on the Case screen. You can then click Apply Case to change the subject for your experiments. Applying a new case will reset the chart below, interrupting any experiments in progress, so be sure you are finished with any previous experiments before applying a new case.
The cases are Normal, Congestive Heart Failure, Hypertension, Mitral Valvular Stenosis.
Nerve Impulses: The Nerve Impulses subscreen shows the firings of four different nerves that are central to the control feedback system regulating cardiovascular function. The nerve impulses are shown dynamically as an experiment is in progress and can be reviewed at the end of an experiment in the same way the chart values can be reviewed (see The Chart below). Nerve impulses that are traced are the Carotid Sinus, Vagus, Sympathetic Cardiac, and Sympathetic Vasoconstrictor.
The values for Mean Arterial Pressure (MAP), Heart Rate, Stroke Volume, Total Peripheral Resistance, and Blood Volume are graphed in the chart at the bottom of the screen during an experimental run. (An experiment is started by clicking the Start button to the left of the chart.) While an experiment is running, the latest value for each variable is shown in the summary box on the far right of the chart.
When an experiment is stopped (by clicking the Stop button to the left of the chart), a red scrollbar will appear at the end of the chart graph. Clicking on the chart will bring the scrollbar to that position. You may also drag the scrollbar. The values in the summary window will reflect the position of the scrollbar. If the chart is longer than will fit on the screen, you may drag the scrollbar to the edge of the chart to make the chart scroll in that direction.
Reset All: Use this button to clear your data and start over with the default settings for all the variables. This button resets any changes you have made to the variables and any interventions you have introduced. It does not, however, change the currently set case.
When you click Export Image, you will be asked to give a title to the image being exported, type in a title that will help you identify this particular experiment and click OK. A new browser window should then appear displaying the chart. You can now print the chart using the print function within your browser.
Main Window: The main section of the Notebook is an editable text box to which you can add text and modify it at any time. The contents of the Notebook are not saved between uses of the Lab; therefore, it is suggested that you "Export" and print the Notebook if you would like a lasting record of your work.
Undo Editing: Use this to erase all the information on a Notebook page.
Export Notes: Export your notes to a Web browser window for printing or saving.