Exercise 1
Try changing the arterial resistance to 150% of normal and run the model.

(Click Run button. Remember to do at least two successive runs in order to observe the full effect of the changes and allow the patient to adjust)
Q - What happens to the blood pressure and heart rate?
Explain the observed changes.

Q - What might give rise to the altered arterial resistance in a natural situation?

Exercise 2
Now look at the effect of increasing and of reducing each of the first three changeable factors separately
- Arterial Resistance
- Venous Resistance
- Cardiac Pump Performance
Restart the run following each set of results to ensure you start with a healthy 70 kg 40-year-old male volunteer for each run.

Next:
1. Alter the intrathoracic pressure to 0 mm Hg and observe the effects
2. Try the effect of increasing blood volume to 6 litres
3. Try decreasing it to 3 litres

Look especially at the capillary pressure and cardiac output values. Remember that a rise in capillary pressure will force fluid out of the blood system and into the interstitial fluid bathing the capillaries.
Q - Can you suggest real situations where the changes you have made would be likely to occur?

Exercise 3
You are now going to kill MACMAN in the interest of scientific understanding.

Restart with a new patient and examine the effects of progressive blood loss by altering blood volume. Try reducing the blood volume slowly and rapidly.
Q - Does it make any difference if the blood loss is fast or slow? Q - What is the eventual cause of death?

Exercise 4
So far, all of the changes have been carried out one at a time. The programme will also allow you to make multiple changes before you continue running the model.
Now try adjusting the blood volume AND the cardiac pump performance together. This might occur in a severely injured patient who already has coronary heart disease.
Q - How much more serious is severe blood loss in a person with only 50% normal cardiac performance?

Exercise 5
You are now going to change another important influence: the baroreceptor system. The baroreceptors are responsible for maintaining blood pressure in response to changed conditions in the circulation.
First, change the arterial resistance again to 150% of normal. Now select cut the buffer nerves (click on Model) and run two more cycles.
Observe and explain the effects.
Q - Would this kill the subject and if so, what would be the eventual cause of death?

Attachment:- Worksheet and tables.rar