Physiology 2130 Study Guide - Midterm Guide: Salivary Gland, Retina, Frontal Lobe
22 Mar 2018
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Document Summary
The maintenance of relatively stable conditions within the internal environment. External environment: region outside the body, digestive, respiratory and urogenital tracts. Contain a set point, a control center (integrator), an effector, a controlled variable and sensor (receptor) Ex: heating system in house, set point is temp at which room is set (ie: 20c), effector is furnace, controlled variable is heat, control center and sensor is thermostat. Negative (feedback) control because the heat eventually shuts down its own production. In body: temperature set point is 37c, when it is too high nervous system signals hypothalamus, which dilates blood vessels to skin and sweat glands produce sweat, losing heat to outer environment. When it is too low sweat glands inactive, reduced blood flow to skin, muscles contract involuntarily (shivering). Self-amplifying, producing a very rapid change in a system. Ie: generation of action potential in nerve cells.
