CAS BI 211 Lecture Notes - Lecture 1: Organism, Childbirth, Negative Feedback
9 Sep 2016
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Levels of organization: organism, organ systems, organs, functional units (smallest functional part of an atom) Body fluid compartments: body 55-60% water, 2/3 intracellular (within the cells, 1/3 extracellular c. i. plasma (20-25% of ecf) c. ii. interstitial fluids around/between cells. Homeostatic mechanisms compensate for changing environments: sweating, shivering, goose bumps, curling up, etc, mechanisms may be behavioral (curling up), physiological (shivering), or both. Feedback systems: the product of a homeostatic mechanism will turn the mechanism off (ex. Body temp regulation, sweating, shivering, etc. : negative feedback loops are self limiting, positive feedback loops are not self limiting c. i. Childbirth, oxytocin released when the baby pushes on the cervix, causing contractions, which causes the baby to push on the cervix more, and so on c. ii. Basically the reward has to be worth it c. ii. 1: negative feedback loops are often used to control production, secretion, or activation of a chemical product.
