Homeostatis

 Homeostatis and the Human Body 

Terms and Nomenclature  

Homeostatis: The ability of the human body to maintain relatively stable internal conditions even though the outside world changes continuously. (Literal translation: "unchanging")

Dynamic State of Equilibrium: Balance in which the internal conditions vary, but always within relatively narrow limits.

Homeostatic Control System: Entire system of communication that helps the body maintain a dynamic state of equilibrium and, ultimately, homeostatis.

Variable: This is the term for the factor or event that is regulated during homeostatis.

Receptor: First component of the homeostatic control system that senses/monitors the environment and responds to changes by sending information to the control center.

Stimuli: Changes in the environment that the Receptor responds too.

Afferent Pathway: Input signals and Information travel through this pathway between the Receptor and the Control System during homeostatis.

Control Center: Second component of homeostatis that receives input from the Receptor (via the Afferent Pathway) and decides both the set point and appropriate response or course of action. It then sends information to the Effector (via the Efferent Pathway).

Efferent Pathway: Output Signals and Information travel through this pathway between the Control System and the Effector during homeostatis.

Set Point: Level or range at which a variable is to be maintained. This is set in the control center of the homeostatic control mechanism.

Effector: Third component of homeostatis that receives output from the Control Center and provides the means for the control center's response to the stimulus. 

Feed back: Results of the Response to influence the effect of the stimulus by either reducing it so that the whole control process is shut off, or enhancing it so that the whole process continues at an even faster rate. 

Negative Feedback Mechanisms: Feedback that reduces the effect of the stimulus so that the whole control process is shut off or has a reduced intensity. These mechanisms cause the variable to change in a direction opposite to that of the initial change, returning it to its "ideal" value.

Positive Feedback Mechanisms: Feedback that enhances the effect of the stimulus so that the response is accelerated. The change that results proceeds in the same direction as the initial change, causing the variable to deviate further and further from its original value or range. 

Often referred  to as Cascades.

Homeostatic Imbalance: The resulting disturbance of the homeostasis that is most often labeled as a disease. Occurs when the body's control systems become less and less stable, negative feedback mechanisms are overwhelmed and positive feedback mechanisms take over.

Images and Diagrams