ultradian and infradian rhythms

HideShow resource information
View mindmap
  • ULTRADIAN AND INFRADIAN RHYTHMS...
    • Ultradian rhythms
      • biological rhythms are reffered to as ultradian if its period is shorter than 24 hours.
        • an example = 5 stages of a typical nights sleep.
          • the sleep cycle repeats itself every 90-100 minutes.
          • the ultradian rhythm found in human sleep follows a pattern of alternating REM and NREM which consitsts of slages 1-4
            • REM= rapid eye movement
            • NREM= non-rapid eye movement i.e. sleep
          • different stages have different durations. a complete cycle consists a pregression through the 4 stages of NREM sleep before entering the final stage of REM  sleep then it starts all over again.
            • what we know about these stages of sleep comes from an ECG pattern and recording the electrical activites if the brain.
              • each stage has a distinct ECG pattern.
              • the ECG of a person in REM is like they are awake as they are dreaming.
          • STAGES
            • 1) light sleep, muscle activity slows, occasional twitching.
            • 2) breathing pattern and heart rate slows, decrease in body temp
            • 3) deep sleep, brain begins to generate slow delta waves.
            • 5) rapid evy movement brian waves speed up dreaming occurs! muscles relax and heart reate increses. breathing is rapid and shallow.
        • the basic rest activity cycle
          • Kleitman reffered to the 90 min cycle found during the day. - we move from a state of alertness to a state of physiological fatigue.
          • research suggests that the human mind can focus for a period of about 90 mins. - toward the end the body runs out of resources and loses concentation and become fatigue.
          • the operation of the BRAC in wakefulness is not as obvious as it is in sleep but every day observations suggest this, i.e coffee break at 10.30 breaking up 9-noon into 2 90 min period
    • Infradian rhythms.
      • Have a duration greater than 24 hrs- longer than circadian rhythms.
        • they may last weeks, months, or may be annual
          • weekly rhythms.
            • male testosterone levels are higher at the weekend.
            • young couples report more sexual activity at weekend than on weekdays.
              • however birth levels are lower at weekends than weekday
                • male testosterone levels are higher at the weekend.
            • Halberg et al reported seven-day rhythms of blood pressure and heart rate in human-evidence is unclear.
          • monthly rhythms.
            • the human menstrual cycle.
              • it lasts about one month.
                • there are considerable variations in the length of the cycle, 23-days-36 days.
                  • ovulation occurs halfway through the menstrual cycle- when oestrogen levels are at peak.
                    • usually it lasts 16-32 hours - after the phase progesterone levels increase in the prep for possible implantation of an embryo in the uterus.
                • the cycle is regulated by hormones.
                  • they either promote ovulation
                  • or stimulate the uterus for fertilisation.
          • annual rhythms
            • In animals annual rhythms are related to seasons
              • i.e. migration and hibernation
            • In humans, the calendar year appears to influence behaviour regardless of changes in temperature.
              • research suggests a seasonal variation in moods- especially in women.
                • some become severely depressed in winter.
                • there is an increase in heart attacks in winter.
                • the death rate is at its peak in January
  • STAGES
    • 1) light sleep, muscle activity slows, occasional twitching.
    • 2) breathing pattern and heart rate slows, decrease in body temp
    • 3) deep sleep, brain begins to generate slow delta waves.
    • 5) rapid evy movement brian waves speed up dreaming occurs! muscles relax and heart reate increses. breathing is rapid and shallow.

Comments

No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Cognitive Psychology resources »