Discussion Exercises

1. Compare Rigg's Span of Control with Empirical Observations
According to the 9th Edition of Guyton and Hall's "Textbook of Medical Physiology" (p. 916):

In general, a nude body in dry air between 55 degrees and 130 degrees F is capable of maintaining a normal body core temperature somewhere between 97 degrees and 100 degrees F. The temperature of the body is regulated almost entirely by nervous feedback mechanisms, and almost all of these operate through temperature regulating centers located in the hypothalamus.

How does this observation compare with Rigg's model calculations indicating a span of control from 5 degrees to 45 degrees C?

2. Compare Rigg's Modeling with System Dynamics Modeling:

Review Riggs' description of the model on pages 384-400 and address the following questions about his approach.

Why does Riggs confine his attention to the equilibrium conditions?

Could Riggs use the model to show behavior over time?

Do his loop diagrams follow the conventions explained in Modeling the Environment?

Do his "electrical" diagrams follow the conventions in Modeling the Environment?

How effective are his loop diagrams and his "electrical" diagrams in helping you to appreciate the underlying structure of his model?