Many variables in the human body are under feedback control. For each of the following controlled variables, draw a graph showing the process being controlled, the sensor that measures the variable, the actuator that causes it to increase and/or decrease, the information path that completes the feedback path, and the disturbances that upset the variable. You may need to consult an encyclopedia or textbook on human physiology for information on this problem.
Source: From Astrom (1970, p. 192); reprinted with permission
(a) Blood pressure
(b) Blood sugar concentration
(c) Heart rate
(d) Eye-pointing angle
(e) Eye-pupil diameter