HOMEOSTASIS n An organisms ability to maintain a
HOMEOSTASIS n. An organism’s ability to maintain a constant, stable internal environment.
HOMEOSTATIC MECHANISMS n Operate by the interaction of 3 components: § § § Receptors-sensitive to stimuli Control Center-receives & processes information Effectors-cell or organ that responds
FEEDBACK MECHANISM EXAMPLES n n n http: //www. bbc. co. uk/schools/gcsebitesize/science/add_aqa _pre_2011/homeosts. shtml http: //www. youtube. com/watch? v=CLv 3 Sk. F_Eag Book Animation
HOMEOSTATIC MECHANISMS n Classified as: Negative Feedback Mechanisms or Positive Feedback Mechanisms
NEGATIVE FEEDBACK MECHANISMS n n Operate to bring the internal environment back to the homeostatic, or normal, state They work in such a way that they negate, or oppose the change that has occurred from the normal, homeostatic state They slow or stop a process Examples; regulation of body temperature, blood sugar, blood oxygen level, heart rate, respiration rate, and p. H levels in the stomach http: //www. pennmedicine. org/health_info/diabetes 2/000272. html
POSITIVE FEEDBACK MECHANISMS Operate to increase the deviation from the normal, homeostatic state n Usually only operate in specific situations and for short periods of time n They speed up a process n Examples; blood clotting process, the labor process, and many enzymatic reactions n
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