5. Glossary
Homeostasis: the physiological state of the body which internal
physical and chemical conditions are kept within a range that is
suitable for life processes
Homeostatic mechanism: a system that monitors internal and
external conditions and changes bodily functions to maintain
homeostasis
Negative Feedback: the response of a system that acts to maintain
equilibrium by compensating for any changes made to the system
Sensor: the element of a feedback system that detects changes in the
environment
Integrator: the element of a feedback system that compares existing
conditions with ideal conditions
Set Point: the optimal value for a given variable of a system
Effector: the element (or elements) of a feedback system that act to
return the system to its optimal state
Positive Feedback: the response of a system that acts to increase
the effect of any changes made to the system
6. Thermoregulation: the regulation of internal temperature by negative
feedback mechanisms
Homeotherm : an animal that maintains a stable body temperature
regardless of the temperature of the external environment
Poikilotherm: an animal whose body temperature caries with, and
often matches, the temperature of the external environment
Endotherm: an animal that maintains its body temperature by internal
mechanisms
Ectotherm: an animal that maintains its body temperature by
absorbing thermal energy from the environment
Thermal acclimatization: the process by which an animal gradually
adjusts to temperature changes in its environment
Torpor: a short-term state of reduced metabolic rate and body
temperature that reduces the demand for energy during the night or
day
Hibernation: a state of greatly reduced metabolic rate and activity
that enables an animal to survive the winter by reducing the demand
for energy when food is unavailable
Estivation : a state of torpor that enables an animal to survive the
summer by reducing the demand for energy
