PSY 454 Lecture Notes - Lecture 12: Pituitary Gland, Jet Lag, Zeitgeber
Document Summary
Humans dominated by a circadian rhythm of daylight activity and nocturnal sleep. Daily cycles in humans: pulse rate, blood pressure, body temperature, rate of cell division, blood cell count, alertness, urine composition, metabolic rate, sexual drive, feeding behavior, responsiveness to medications. Behavior not only cued from the environment. Regulates feeding times, sleeping times, and metabolic activity. Time required to complete a cycle of activity. Less than a year (e. g. , human menstrual cycle) Less than a day (e. g. , eating cycle) Body rhythm devised in absence of external cues. Human body has its own rhythms with a period of 25-27 hours. Sleep-wake cycle shifts an hour or so every day. Animals expand and contract their sleep periods as the sleep-related lighting period expands or contracts. How circadian rhythms synchronize with seasonal changes in daylight. Neural basis of the biological clock: suprachiasmatic rhythms. Main pacemaker of circadian rhythms; located just above the optic chiasm. Intergeniculate leaflet & pineal gland clocklike activity.
