PSYA01H3 Lecture Notes - Lecture 17: Ernest Hilgard, Orexin, Brain Death
Document Summary
5. 1: biological rhythms of consciousness: wakefulness and sleep. Consciousness: a person"s subjective awareness, including thoughts, perceptions, experiences of the world and self-awareness. Alternating cycles of consciousness are sleeping and waking. Biological rhythms are patterns that organisms have created for their daily life. E. g. bears hibernate in the winter, but since this a yearly cycle it is called circannual rhythm. Infradian rhythm: any rhythm that occurs for more than a day e. g. menstrual cycle bear, urination. Ultradian cycles: biological rhythms that occur more frequently, e. g. heart. Circadian rhythm: internally driven daily cycles of about 24 hours affecting physiological and behavioral processes. Cells in the retina send messages about light levels to the scn (suprachiasmatic nucleus in the hypothalamus) which then communicates with the pineal gland: The pineal gland releases the hormone melatonin which is high at nighttime and this info about melatonin is sent back to the hypothalamus.
