BIOL 2160 Test 1 notes

BIOL 2160 Test 1 notes - C hapter 1 The Study of Body...

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Chapter 1: The Study of Body Function What is “physiology”? - Literally – the study ( logos ) of nature ( physics ) - Modern sense – the study of biological processes or functions o “how things work” - Concerns the normal functions of cells, tissues, organs, and systems - Emphasizes mechanisms - 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 begins by studying the effects of a chemical on cells in vitro (in a culture dish). - Next, 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. - Phase I clinical trials test the drug on healthy human volunteers to test for side effects, rates of passage, dosage, etc. - Next the drug goes into phase II clinical trials to test its effectiveness on people with the particular disease. - Phase III 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. - Phase IV trials test other applications for the drug. o 10-20 years for phase I-III I I. Homeostasis and Feedback Control Homeostasis
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- The ability to maintain a relatively stable internal environment despite fluctuations in the external environment - 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 Negative Feedback Loops - 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 then sends instructions to an effector. o Effector makes the appropriate adjustments. - Body temperature: o Sensors in the brain detect deviation from 37°C. Another part of the brain assesses this as actionable, and effectors (sweat glands) are stimulated to cool the body. o Once the body is cool, sensors alert the integrating center, and sweat glands are inhibited. o The end result regulates the entire process. Production of the end product shuts off or down-regulates the process. This is why it is called a negative feedback loop. Antagonistic Effectors - Homeostasis is often maintained by opposing effectors that move conditions in opposite directions.
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BIOL 2160 Test 1 notes - C hapter 1 The Study of Body...

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