BIO 208 Lecture Notes - Lecture 25: Physical Chemistry, Dynamic Equilibrium, Endocrine System
Document Summary
Body, systems, organs, tissues, cells, organelles, proteins, lipids, ion channels, biochemistry, physical chemistry, physics: homeostasis (negative feedback)- staying the same - dynamic equilibrium - maintaining the internal state within narrow limits even during external change. How is homeostasis maintained: auto regulation (intrinsic regulation) Occurs when the activity of a cell/ tissue/ organ adjusts automatically in response to environmental change: extrinsic regulation. Changes result from the actions of the nervous or endocrine systems: general regulatory mechanism consists of: Cell/organ that responds to control center commands to oppose or minimize the change: negative feedback. Response shuts off or mitigates original stimulus. Change proceeds in direction opposite that of stimulus. Maintain a xed range of values not one speci c value: positive feedback. Proceeds in the same direction as the change. Used for ampli cation (always followed by negative feedback) - growing. Regulates a stressful process that must be completed quickly.
