Chapter 4

Chapter 4 - Chapter 4 States of Consciousness- varying...

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Chapter 4 States of Consciousness- varying awareness of the external world and ourselves Biological Rhythms Cyclic changes in bodily processes Circadian rythms-clyclic changes occurring within a single day Ultradian rhythms- occur frequently…eating Infradian rhythms- occur more then 24hrs…period Suprachiasmatic nucleus- a portion of the hypothalamus that seems to play and important role in the regulation of circadian rhythms. The pineal gland releases melatonin a hormone that releases fatigue. Seasonal Affective disorder- depression typically occurring in the winter months possibly due to lack of sun. Disturbances in Circadian Rhythms Jet lag- when individuals feel tired and considerable difficulty in adjusting to their new location Shift work- working at night Sleep An activity in which important physiological changes are accompanied by major shifts of consciousness Electroencephalogram- a record of electrical activity within the brain. Plays a role in the study of sleep o Electromyogram- muscle activity o Electro-ocularam- eye activity The basic Nature of Sleep When one is awake your EGG contains beta waves which are replaced with alpha waves when individuals are awake but relaxed. This is due to chemical changes in the brain which may take up to ten minutes. There are four different stages of sleep o 1(alpha)- theta waves, breathing slows, loss of muscle tone, relaxation o 2- brain emits sleep spindles or high voltage waves, which help us, remain asleep and enter different stages of sleep. Half sleep time in this stage o 3(gama)+4(delta)- marked by increasing appearance of delta wave; high amplitude waves which occur during stages of sleep specifically 3 and 4 slowing down all bodily functions. Rapid eye movement- a state of sleep in which brain activity resembling waking restfulness deep muscle relaxation and movements of the eyes. This stage usually happens 90 minutes after sleep and is the stage in which dreams usually occur.
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Functions of Sleep Recuperative theory- a theory suggesting that while repair of the body goes on during our waking hours, repair of the brain happens during sleep. Evolutionary theory- a theory suggesting that sleep evolved to ensure that various
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Chapter 4 - Chapter 4 States of Consciousness- varying...

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