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Biology Ch.9.1 Terms
Homeostasis and Circulation
Term | Definition |
---|---|
Homeostasis | "Steady state". The body's maintenance of a relatively stable internal environment despite a changing external environment. |
Dynamic Equilibrium | State of balance achieved within an environment as the result of internal control mechanisms that continuously oppose forces that tend to change that environment. |
Homeotherms | (___=same, _____=temperature). These organisms keep their body temperature relatively constant. (Eg. birds and mammals) |
Poikilotherms | Animals whose body temperature fluctuates depending on the temperature of their environment. (Eg. cold-blooded animals like turtles, lizards, snakes) |
Vasoconstriction | The constriction of blood vessels. |
Vasodilation | The dilation of blood vessels. |
Negative Feedback Loop | The body's reaction to increased or decreased temperature. A process that detects and reverses deviations from normal body temperature or other constants. Essential to maintain homeostasis. |
Positive Feedback Loop | Rare in healthy bodies. Acts to move a system away from balance and stability. Usually associated with disease or change. |