Homeostasis vs. Steady-State
When the body’s biological control systems maintain physiological variables at manageable constant values at rest, it is called homeostasis. More specifically, the term homeostasis describes the maintenance of an unchanging/constant “normal” internal environment by a biological control system, where a physiological variable (e.g. body temperature) remains within a normal range when the body is not under any stress (e.g. at rest). On the other hand, the term steady state describes the maintenance of an internal environment by a biological control system, where a physiological variable (e.g. body temperature) remains relatively constant yet deviates from its normal value, which occurs when the body is experiencing stress (e.g. exercise). Due to the external stress the body cannot maintain a normal constant internal environment and has to make adjustments in order to retain a constant environment under stress, where the body’s response to the external stress is equal to its magnitude. In other words, the term homeostasis is being used to describe the body’s maintenance during resting conditions whereas the term steady state refers to the body’s maintenance during exercise; exercise is a stressor which disrupts homeostasis, also called homeostatic disturbance (e.g. an increase in temperature). More specifically, homeostatic disturbances occur at the cellular level causing a temporary decrease in O2 levels, whereas the CO2 levels go up, which causes acidity levels to increase.
The body’s metabolic changes are regulated by biological control systems in the same manner an air conditioning unit responds to changes in outside temperature to maintain indoor temperature at a certain constant level.
Biological Control Systems
In order to track metabolic changes the body has numerous biological control systems that monitor the body’s internal environment; the biological control systems’ task is to maintain a physiological variable (e.g. blood pressure or body temperature) at a manageable constant value. How exactly these control systems operate remains under investigation but each biological control system consists of a(n):
Receptor Control center Effector
When a homeostatic disturbance in the internal environment occurs a signal arises, called stimulus. The stimulus excites the receptors, which send a message to the control center. The control center assesses the strength of the stimulus (message, situation) and sends out an appropriate response to the effector to correct the disturbance, thereby returning the internal environment back to” normal” (manageable constant values), hence removing the stimulus.
