Physiological Control Systems 1 and 2 (PCS1 / PCS2) are an exploration of how the human body controls itself to maintain a stable internal environment with the special emphasis of an engineer's perspective. The course examines both physiological and nonliving (engineered) control systems that use negative feedback control systems. For instance we will compare control systems used by the human body and by engineers to maintain a human body’s or an oven’s temperature. Our ultimate goal will be to consider the technological challenges faced by NASA in the development of space vehicles such as the ones used in the ill-fated Apollo 13 moon mission that were used to carry three humans into outer space while maintaining their homeostatic mechanisms that use negative feedback control systems.

A negative feedback control system for a variable, such as temperature, requires: 

1. a sensor to detect the presence and condition of the sensed variable, 
2. a method of communicating (a.k.a. an afferent pathway) the status of the variable to a control center,
3. a control center (a.k.a. an integrating center) that accumulates sensor input and compares the status of the variable under control to a standard desired value known as a set-point,
4. a method of communicating (a.k.a. an efferent pathway) “decisions” from the integrating center out to mechanisms (a.k.a. effectors) that will change the status of the variable,
5. effectors which create a response which changes the system to oppose the direction of any changes in the variable (a.k.a. a stimulus).

As you may have surmised, a negative feedback control system is also known as a stimulus-response system in which the response is opposite to the stimulus and the value of the variable is maintained within an acceptable range.

In order to understand how engineers succeed with the challenges of human space flight, the circulatory, endocrine, nervous, renal and respiratory systems will be examined from the perspective of how they are used in control systems used in the human body to maintain homeostasis. Homeostasis is the maintenance of a constant internal environment. 

Many times I have heard a pre-engineering student ask: Why do I need to learn biology?

My answer focuses on the challenge of a large percentage of engineering tasks which is to design and build some product that will influence the way we live.  In many cases these products, if they fail, may place our lives in jeopardy.  So my answer is: 

How can you build something for a human if you do not undersatnd what a human is? Of course what a human is, is very involved with HOW a human functions.  How a human works is called physiology and that is what this course is all about.

An emphasis will be made to discuss the importance of understanding physiological control systems from an engineer's perspective when trying to design:

1. micro-environments needed to maintain a human body in a hostile environment (e.g. a space suit or space ship) or 
2. replacement parts for the human body. 

To address these issues, in PCS 2, the feature film Apollo 13 will be analyzed to learn how difficult it is to engineer a fail-safe artificial environment for humans.

Physics principles involving force, pressure, fluid flow, electron flow, electrical potentials, pressure gradients, resistance, viscosity, elasticity, etc. will be used to explain how:

1. the circulatory system works to move blood,
2. the endocrine system sends chemical messages,
3. the nervous system sends electrical and chemical messages,
4. the renal and respiratory systems are used in the management of blood gases and waste molecules.
5. the gastrointestinal tract moves material through its very long tube
   

Anatomical structures will be required as needed, but will NOT be a focus. In other words, students do not memorize all the names of the bones in the body, but are expected to know all the parts of the circulatory system because one can not discuss its function without knowing the names of its parts. To learn structure without the associated functions is worthless for an engineer.