Chapter 5 Outline

Chapter 5 Outline - 5. Body Rhythms and Mental States...

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5. Body Rhythms and Mental States Biological Rhythms: The Tides of Experience Biological rhythms are typically in tune with external time cues, such as changes in clock time, temperature, and daylight, but many rhythms continue to occur even in the absence of such cues; they are endogenous , or generated from within Circadian rhythms are biological rhythms that occur every 24 hours o Best known is the sleep-wake cycle o Body temperature fluctuates about 1° centigrade each day o In the animal world, birds migrate south in the fall, bears hibernate in the winter Circadian rhythms o Exist in plants, animals, insects, and human beings o Reflect the adaptation of organisms to the many changes associated with the rotation of the earth on its axis, such as changes in light, air pressure, and temperature o In most societies, clocks and other external time cues abound, and people’s circadian rhythms become tied to them, following a strict 24-hr schedule o Circadian rhythms are controlled by a biological clock located in a tiny cluster of cells in the hypothalamus called the suprachiasmatic nucleus (SCN) o The SCN regulates fluctuating levels of hormones and neurotransmitters and they in turn provide feedback that affects the SCN’s functioning o Melatonin induces sleep o When your normal routine changes, your circadian rhythms may be thrown out of phase o Internal desychronization – a state in which biological rhythms are not in phase with one another o Sleep and wake patterns usually adjust quickly, but temperature and hormone cycles can take several days to return to normal o One reason that a simple cure for desynchronization has so far eluded scientists is that circadian rhythms are not perfectly regular, they can be affected by illness, stress, fatigue, exercise, excitement, drugs, mealtimes, and ordinary daily experiences o Circadian rhythms differ greatly from individual to individual because of genetic differences Moods and long-term rhythms o Does the season affect moods?
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Clinicians report that some people become depressed during particular seasons, typically winter, when periods of daylight are short, known as seasonal affective disorder (SAD) However, for many people who get the winter blues, the reason could be that they hate cold weather, are physically inactive, do not get outside much, or feel lonely during the winter holidays o Does the menstrual cycle affect moods? Controversy has persisted about the menstrual cycle The interesting question for psychologists is whether these physical changes cause emotional or intellectual changes Most people assume, uncritically, that many women “suffer” from “PMS” The Rhythms of Sleep Sleep puts us at risk: muscles that are usually ready to respond to danger relax and senses grow dull The realms of sleep o During sleep, periods of rapid eye movement (REM) alternate with periods of fewer eye movements, or non-REM sleep in a pattern that recurs every 90 min or so, REM periods last from a few min to as long as
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This note was uploaded on 02/05/2011 for the course PS 101 taught by Professor Hoffman during the Fall '07 term at BU.

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Chapter 5 Outline - 5. Body Rhythms and Mental States...

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