BIOL 2160 Test 1

BIOL 2160 Test 1 - B IOL 2160 Human Physiology C hapter 1:...

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BIOL 2160 – Human Physiology Chapter 1: The Study of Body Function Framework for Physiology – half of what we are taught is wrong. What is “ Physiology ”? Literally the study ( logos ) of nature ( physis ) Modern sense the study of biological processes or functions o “how things work”, “what causes…”, etc. Concerns the normal functions of cells, tissues, organs, and systems Emphasizes mechanisms What we know from physiology is derived from scientific research, much of which is directed towards the treatment of disease Developing Pharmaceuticals Basic research is conducted for years before a drug is ever given to a person. Research usually begins by studying the effects of a chemical on cells in vitro (in a culture dish). Next, the studies are done in animals (usually rats and mice) to see if the same effects occur in vivo (in a living creature) and if there are any toxic side effects. o For these trials, many rats and mice are genetically modified to be susceptible to particular diseases. o Animal trials may take several years. Everything that we know about diseases comes from these studies. Phase I clinical trials test the drug on healthy human volunteers to test for side effects, rates of passage, dosage, etc.
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Next the drug goes into Phase I I clinical trails to test its effectiveness on people with the particular disease. Phase I I I clinical trials are conducted on a large number of people to include both sexes, many age groups and ethnicities, and people with more than the one health condition. From here the FDA can approve the drug for sale. o Most drugs do not make it to this phase. (After FDA approval) Phase IV trials test other applications for the drug. Homeostasis and Feedback Control Homeostasis Homeostasis the ability to maintain a relatively stable internal environment despite fluctuations in the external environment. o When you are hot you sweat… and when you are cold you shiver Essential for survival and function of all cells. Each cell contributes to maintenance of a relatively stable internal environment. Deviation from homeostasis indicates disease. Homeostasis is accomplished most often by negative feedback loops. o So each cell maintains a relatively constant environment . Negative Feedback Loops
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Involve: o Sensors in the body to detect change and send information to the integrating center o Integrating center assesses change around a set point. The integrating center sends instructs to an effector. o Effector makes the appropriate adjustments. Body temperature : o Sensors in the brain detect deviation from 37 degrees C. Another part of the brain assesses this as actionable, and effectors (sweat glands) are stimulated to cool the body.
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This note was uploaded on 06/01/2011 for the course BIOL 2160 taught by Professor Kt during the Summer '08 term at LSU.

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BIOL 2160 Test 1 - B IOL 2160 Human Physiology C hapter 1:...

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