Biological Rhythms and Sleep unit 3 Specification 1

Biological Rhythms and Sleep (unit 3) Specification 1. Biological Rhythms- Circadian, Infradian and Ultradian and disruption of rhythms 1. Sleep- Stages, Lifespan changes, function of sleep 1. Sleep disorders- Explanations for disorder including insomnia, sleep walking and narcolepsy

Starter What is a Biological Rhythm? What controls/changes our rhythms? What can effect sleep/ our biological rhythms?

Highlighting • Provide two examples of why highlighting is ineffective • Provide two examples of how highlighting can be effective • Do you want to use a highlighter?

The Best Approach • Read an assigned text quickly -- first for a general overview -- then go back and seek out the details. • View yourself as a translator of the material, with your job being to translate the text into your own language • Keep a pen or a pencil, not a highlighter, in your hand. Underline important passages and define terms through your own eyes • Write notes, questions and reactions in the margins. When you read you should be having a conversation with the text. • Don't let it do all the talking -- react to it. Your response helps you formulate the meaning of the text. • Read actively.

Intro to Biological Rhythms A biorhythm is a pattern of physiological or psychological processes which repeats itself over a specified period of time. • Circadian (latin circa= approximately, dian = 24 hrs) • Ultradian (ultra= greater (they occur more than 24 hrs) (e. g sleep cycles) • Infradian (infra= lower (occur less than every 24 hours) ( e. g menstrual cycle)

Swap your posters • Describe each stage on your new comic strip • Hand back to the original group for marking

Circadian rhythms These are rhythms that last 24 hours, such as the sleep wake cycle. Our bodies have many other circadian rhythms, such as temperature regulation and bowel regulation.

Circadian rhythms – practical applications Make three suggestions/recommendations based on the following

Pacemakers and zeitgebers • Endogenous pacemakers are a biological factor inside you (hormones) that sets your rhythm • Exogenous zeitgebers are things that are outside of your body, so external to you, that set your rhythm (light) The sleep-wake cycle is primarily controlled by EP’s but it can also be synchronised by EZ’s. The sleep-wake cycle exists without light but light influences the cycle

The Biological Clock - How does it work? Thought mainly to be an endogenous (internal) mechanism • Our internal rhythms are though to be generated by protein synthesis within the SCN. Protein is produced for a period of hours until it reaches a level that inhibits further production. Over the next few hours the protein level gradually falls, when it drops to a certain ‘threshold’ level then production of the protein re-starts. This generates an internal (endogenous) biological rhythm – in humans of between 24 ½ and 25 hours. • This endogenous rhythm is regulated to keep it in line with our environmental rhythms by an exogenous mechanism

Exogenous Zeitgebers (external mechanism) • SCN have a nerve input directly from the retina of the eye, so they are kept informed about the zeitgebers of light and darkness. • In darkness this information is transmitted to the pineal gland which manufactures melatonin a hormone which stimulates the production of serotonin in the raphe nucleus this hormone causes reduced levels of arousal and so induces sleep. • When Light enters through the eyes it stimulates the SCN to produce an inhibiting factor (probably a protein) This inhibits the production of melatonin by the pineal gland so maintains arousal levels – keeping you alert and awake!

Pineal Gland Endogenous Pacemaker Internal Temperature light Exogenous Zeitgebers Superchiasmatic nucleus Melatonin

Nature vs Nurture or Determinism • IDA- A mixture of environmental and biological determinism interact to control your circadian rhythms. • This is because we definitely know that our circadian rhythms are controlled by endogenous i. e. biological factors, however as exogenous zeitgebers for instance light can have an impact on these rhythms that there is an element of the environment also. • So the explanation is an interact of the two and this is definitive.

So What? – Understanding has led to useful applications. E. g. helps us to minimise the unpleasant and harmful effects of disrupting the sleep-wake cycle - shift work and jet lag – It could also help us to deal with people who have circadian rhythm disorders more effectively (this is an additional point – only use it if you are going to find out a little bit about circadian rhythm disorders)

Board: Grounding Group task P 5 • I am going to show you a picture related to a piece of research • You must find the study on page 5 that links • To get the points on the w/b you must explain the study and provide a full grounding • Bonus points for any relevant/useful evaluation you can consider

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Evaluation of Research J Controlled conditions increase confidence in validity. Schochat’s research took place in a well controlled laboratory environment. L Correlation criticisms. Schochat’s relationship is correlational so only proves a relationship not the cause of the relationship. J However insomniacs treated with melatonin do find it easier to sleep. L Validity of animal research is questionable. Extrapolation from animals to humans is an issue in Morgan’s hamster study, though no reason to suppose it would be any different.

Morning Lark or Night owl? • What does this suggest about Circadian rhythm onset?

IDA example for the Circadian Rhythm The Point: The theory enables us to understand how both ______________ and ________________ act together to control the rhythm Explain the Point: This is because theory show that while _____ such as the role of the SCN largely control the rhythm, _____________ , such as light, play a part in … Resetting the rhythm So What? The greater understanding that theory gives us of how the circadian rhythm is controlled, may lead to useful… Applications As it could help us to deal with… People who have circadian rhythm disorders more effectively It could also help us to minimise the unpleasant and harmful effects of Shift work and Jet Lag

Practical Applications • Sleep Hygiene • Use of devices • Work/study schedules • Fitness/ sport regime

What do you know about disrupting circadian rhythms based on the homework 1. Jet Lag 2. Shift work • Use the following terms Zeitgebers, internal and external, disrupts,