Tutorial Stage 3: Inducing physiological changes

1. Select the 'Student Carbohydrate Practical' as in Tutorial 2. At the bottom of the graphs you should see some marks labelled 'E' and 'D'. These ticks represent the times at which Jason 'E'ats a meal and 'D'rinks water. He does this when he feels hungry or thirsty, and this is in turn governed by physiological variables.
   
2. Click the status button (the second button on the toolbar, usually labelled 'Well'). Prevent Jason from eating or drinking anything - for example by selecting 'Restrict all'.
3. Pause the simulation when it has been about 8 hours since Jason last ate a meal (watch the vertical lines that represent hours going by, and check for the last 'E' mark at the bottom of the screen).
4. Give Jason a chocolate bar by pressing the button on the right-hand side. Press the button once and then press play to restart the simulation.
5. Watch the 'Plasma glucose concentration' graph, and note the maximum value it reaches in the hours following the chocolate bar. To find out what the normal value is, hover the mouse cursor over the number on the right hand side of the display. To find the allowed range values, hover over the slider bar on the right of the number
   
6. To access information about the variable, click on the name of the variable in the right-hand panel. Alternatively, double click on the numeric value of the variable. Alternatively you can right-click (or menu-click) the number and select 'Info'. You should see a box showing technical information about a variable, including what other variables influence its value.
   
7. Pause the simulation, and decrease the 'Glucose Tolerance'. Do this by dragging the slider down to, say, 20%. Repeat your experiment and see what happens to the insulin and glucose levels this time. Glucose tolerance is often impaired in type II diabetes mellitus.