NPB 101 Lecture Notes - Lecture 1: Circadian Rhythm, Negative Feedback, Homeostasis
1 Oct 2017
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Document Summary
How does it work: applies physical & chemical principles, to multiple levels of organization, to perform functions of life. When does it work: all the time (24/7, varies with time of day, season, nutrition, activity, etc. Why is it important: normal physiology = healthy, abnormal physiology (pathophysiology) = disease/death. Environment will have an impact on the individual. Cellular: cell is basic unit of life. Homeostasis: a dynamic steady-state of internal environment, not all physiological variables are maintained homeostatically. Regulation: how we obtain homeostasis, feedback control, negative, positive. Maintenance of a relatively stable internal environment: does not mean that composition, temperature, and other characteristics are unchanging, daily variation (ex: circadian rhythms) Homeostasis is essential for survival and function of all cells. Each cell contributes to maintenance of a relatively stable internal environment. Homeostatically regulated variable include: concentration of nutrient molecules, concentration of o2 and co2, ph, concentration of ca2, concentration of water, salt, and other electrolytes, volume and pressure, body temperature.
