BIOLOGICAL RHYTHMS
- Created by: amberholloway
- Created on: 21-05-17 16:37
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- Biological Rhythms
- Infradian & Ultradian Rhythms
- Infradian Rhythm= take longer than a day to complete
- The Menstrual Cycle= endogenous system
- -28 days long= from first day of period to day before next period - Oestrogen= develops egg in ovary & releases it (ovulation) Progesterone= thickens lining of womb, readying body for pregnancy - If not pregnant= egg absorbs into body= menstrual flow occurs
- STUDY= found menstrual cycle could be affected by exogenous factors= other women's cycles - they synchronise due to the influence of female pheromones - 29 women with history of irregular periods - sample of pheromones of 9 women gathered at diff.stages of their menstrual cycle via cotton pad placed under armpit - pads frozen= rubbed on upper lip of other 20 pps - day one= pad from start of MS applied & so on - FOUND= 68% (13/20) experienced changes in their cycle= bringing them closer to the cycle of their odour donor
- -28 days long= from first day of period to day before next period - Oestrogen= develops egg in ovary & releases it (ovulation) Progesterone= thickens lining of womb, readying body for pregnancy - If not pregnant= egg absorbs into body= menstrual flow occurs
- Seasonal Affective Disorder (SAD)= circannual rhythm as it's a yearly cycle
- Form of depression, persistent low mood, lack of activity & interest in life, symptoms triggered during winter months, daylight hours become shorter, the hormone 'meatonin' is involved= during night= pineal gland secretes melatonin until dawn= during winter= dark for longer= melatonin produced for longer= knock on effect on production of serotonin= neuro-transmitter linked with onset of symptom of depression
- The Menstrual Cycle= endogenous system
- Ultradian Rhythm= occur more than once a day
- Sleep Cycle
- - 90 minutes long - 5 stages
- STAGE 1 &2= light sleep, easily woken, brainwave pattern becomes slower, alpha waves
- STAGE 3&4= deep sleep, difficult to wake someone, delta waves
- STAGE 5= REM sleep, "rapid eye movement", REM correlated with experience of dreaming, body paralysed, brain activity speeds up,
- STAGE 3&4= deep sleep, difficult to wake someone, delta waves
- STAGE 1 &2= light sleep, easily woken, brainwave pattern becomes slower, alpha waves
- - 90 minutes long - 5 stages
- Sleep Cycle
- Infradian Rhythm= take longer than a day to complete
- Circadian Rhythm= 24 hour cycle
- Sleep/ Wake Cycle
- Main external zeitgeber that impacts our sleep/wake cycle is 'light'= we are awake when it's light & asleep when it's dark
- Siffre's Cave Study= isolated himself away from natural light= followed his own internal clock to know when to sleep and wake up= his natural circadian rhythm set to just over 24 hrs= SHOWING= light & dark not essential to maintaining ciracidan rhythm
- Main external zeitgeber that impacts our sleep/wake cycle is 'light'= we are awake when it's light & asleep when it's dark
- Core Body Temperature= 37 degrees
- Varies by 2 degrees during the day. 36 degrees at 4am, 38 degrees at 6pm. we sleep when we are at a cooler temp & wake when we are warmer= our temp. rises during last hours of sleep= waking us up
- Sleep/ Wake Cycle
- Patterns of changes in the body activity= influenced by internal body clocks (endogenous pacemakers) & external changes to environment (exogenous zeitgebers)
- Endogenous Pacemakers & Exogenous Zeitgebers
- Endogenous Pacemaker
- Super-chiasmatic Nucleus (SCN)
- Located in hypothalamus, master circadian pacemaker, helps maintain circadian rhythms, light sensitive cells in the eye act as brightness detectors that send messages to the SCN about the light levels= the SCN uses this info to then coordinate the circadian rhythms
- Super-chiasmatic Nucleus (SCN)
- Exogenous Zeitgeber
- Light
- Not only influence sleep/wake cycle, ALSO hormone secretion & blood circulation= STUDY=light can be detected by light receptors other than the eye= 15 pps woken at various times=light pad shone on back of their knees=researchers managed to create deviation of up to 3 hrs of pps normal sleep/wake cycle= light doesn't rely on eyes to influence circadian rhythms
- Social Cues
- Meal times, bed times, research suggests adapting to local times instead of following own feelings of hunger and tiredness is good for dealing with jet lag by en-training circadian rhythms
- Light
- Endogenous Pacemaker
- Infradian & Ultradian Rhythms
- Main external zeitgeber that impacts our sleep/wake cycle is 'light'= we are awake when it's light & asleep when it's dark
- Siffre's Cave Study= isolated himself away from natural light= followed his own internal clock to know when to sleep and wake up= his natural circadian rhythm set to just over 24 hrs= SHOWING= light & dark not essential to maintaining ciracidan rhythm
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