Running an Isometric Contraction simulation

Submitting your job

Go back to the Dashboard page, and then click on the Run Simulation button on the row corresponding to the model that you have saved.

Assume that you are willing to do the Isometric Contraction test. Then click on the Isometric Contraction radio button from the Observations in the Simulation Setup dialog. Click on the Submit button.

When the simulation job is successfully submitted by XB Modeler, the notification dialog appears on your screen. Then click on the Close button.

Looking your simulation results

When the simulation is finished, you receive an email notification as follows.

Dear your_username,

Your isometric contraction simulation has been completed.
You can download the result from Simulation Results page in your dashboard.

model name : tutorial Ca-F regulatory
model note : energy aware
state names: [P_XB, XB_PreR, XB_PostR, N_XB]

Click on the Simulation Results button in your dashboard page.

Click on the Plot button in the top row that corresponds to the latest simulation result.

Then plots of the resultant tension (contractile force per unit volume) and the calcium concentration given by the XB Modeler appear. The calcium ion profile is given from a typical human heart model. Click on the Plot state ratio button. Then the state ratios appear in the bottom. You can adjust the range of horizontal axis by dragging the sliders. By clicking on the Plot state ratio button again, the state ratio plots are redrawn with the same range. You can see how the input (Ca²⁺ concentration) is transformed to the output (Tension). The initial rise is relaxed and the slow decline is sharpen. These are typical effects of the cooperative model applied to the current model. In the second half, the tension is almost equal to zero though a considerable amount of the Ca²⁺ concentration is left. Such a property is required to realize quick relaxation in diastole phase of our heart cycle.

Towards Heart Beat simulation

You have almost finished construction of a complete model including the force regulatory unit. However, there is an important factor still missing in the current model to deal with muscle deformations. When the muscle contracts, the sarcomere length inside changes. Thus the overlap configuration between the myosin and actin filament changes in the contraction. We will include the influence of sarcomere length in our model in Sarcomere Length dependence and Heart Beat simulation.