identification and specimen labeling. Knowing when the specimen was collected may be important. For instance, phenobarbital levels cannot be interpreted appropriately without knowing whether the specimen was drawn just before ("trough" level) or after ("peak level") drug administration. Drug levels cannot be interpreted if they are drawn during the drug's distribution phase (e.g., digoxin levels drawn during the first 6 hours after an oral dose). Substances that have a circadian variation (e.g., cortisol) can be properly interpreted only with knowledge of the time of day the sample was drawn. During specimen collection, other principles should be remembered. Specimens should not be drawn above an intravenous line, as this may contaminate the sample with intravenous fluid. Lysis of cells during collection of a blood specimen will result in spuriously increased serum levels of substances concentrated in cells (e.g., lactate dehydrogenase and potassium). Certain
given to healthy individuals, it seems that their brain circuits involved in fear are affected and there is an increase in trust and generosity. The production of melatonin by the pineal gland is stimulated by darkness and inhibited by light. Melatonin levels peak in the middle of the night and decrease towards the morning. As the days get darker, we become tired more early. The use of artificial light can increase the awake time dramatically. Melatonin release correlates to our circadian cycle the biological clock based on the 24-hour day/night cycle. It is suggested that taking melatonin in the early evening may improve one's ability to fall asleep. However, there is evidence that higher levels of melatonin contribute to SAD a subcategory of depression that is characterized by sleepiness and lethargy. Discuss two effects of the environment on physiological processes. Brain plasticity refers to the brain's ability to rearrange the connections between its
"Chronobiology" is the science of investigating time-dependent changes in physiology. Muscle strength and short-term power output peak in the early evening (4:006:00 P.M.), which coincides with daily maximum body temperature.15 Pain tolerance, at least for arthritis and fibromyalgia, is also highest between 4:00 and 5:00 P.M. But 4:006:00 P.M. workouts never produced the best results for me. I believe this is because the ideal window depends on circadian rhythm and therefore wake time. These variables are almost never accounted for in studies. If we assume an average wake time of 8:00 A.M. for most subjects who have work or classes beginning at 9:00 A.M., and if peak power output and pain tolerance is between 4:00 and 6:00 P.M. in their studies, this corresponds to 810 hours after waking. I am a night owl, and my average wake time is 11:00 A.M. Using this average,16 810 hours
In W. Austin ~ S. Worchel (Eds.), The social psychology of intergroup rela- tions. Monterey, CA: Brooks/Cole. Blass, T. (1999). The Milgram paradigm after 35 years: Some things we now know about obedience to authority. Journal of Applied Social Psychology, 29, 955-978. Blass, T. (2004). The man who shocked the world: The life and legacy of Stanley Mil- gram. New York: Basic Books. Bodenhausen, G. V. (1990). Stereotypes as judgmental heuristics: Evidence of circadian variations in discrimination. Psychological Science, 1, 319-322. Bodenhausen, G. V., Macrae, C. N., ~ Sherman,J. W. (1999). On the dialectics of discrimi- nation: Dual processes in social stereotyping. In S. Chaiken ~ Y. Trope (Eds.), Dual- process theories in social psychology (pp. 271-290). New York: Guilford. Boen, F., Vanbeselaere, N., Pandelaere, M., Dewitte, S., Duriez, B., Snauwaert, B., Feys, J., Dierckx, V., ~ Van Avermaet, E. (2002)
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