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EXAM FOCUS Biological Rhythms. Connect What questions do you think might come up on what we have studied so far?

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Presentation on theme: "EXAM FOCUS Biological Rhythms. Connect What questions do you think might come up on what we have studied so far?"— Presentation transcript:

1 EXAM FOCUS Biological Rhythms

2 Connect What questions do you think might come up on what we have studied so far?

3 Objectives  Today you will  Consider types of exam questions  Consider material you could use to answer these questions  Consider requirements of these questions  So that you can  Plan and produce answers to cover the possible exam questions at least to your target grade standard

4 June 12  Outline one or more examples of ultradian rhythms. (4 marks)  (This should be about a 100 word answer – no AO2 needed)

5 January 11  Discuss the role of endogenous pacemakers in the control of one or more biological rhythms. (9 marks + 16 marks)  (This is just like the newer 24 mark essays. It should be around 200 words of AO1 – and 8 MRI points including at least 1 IDA)

6 What else could you get?  Outline one or more examples of infradian/circadian rhythms (4 marks)  Describe and evaluate research on circadian rhythms (8+16 marks)  Describe and evaluate research on infradian and ultradian rhythms (8+16 marks)  This question could be split into two lots of (4+8 marks)

7 The importance of IDA  If you look at the mark scheme for this unit, you will see that without using IDA at least once in your essays (12 or 24 markers) you cannot reach the top band for AO2.  This means that you would be losing at least 4 marks (This could be a whole grade!)  But what could you include?

8 A2 Psychology: IDA Superheroes ISSUES The Animal AceMaster Ethnocentric Gender Bias Beauty The Ethics Kid Questioning the usefulness of animal research. Can animal behaviour be applied to humans? Kitty says no! Passionate that theories are prone to culture bias, The Master of Ethnocentrism would die to prove that theories which are Ethnocentric cannot be applied to all cultures. Ironically, the Gender Bias Beauty wants equal application of theories to both Genders. Her pet hate is when theories or studies can only be generalised to one gender or only explain behaviour in just men or just women. Can a theory or study be criticised on the grounds of ethics? Is it unethical? The Ethics Kid is here to find out!

9 A2 Psychology: IDA Superheroes DEBATES Nature-Man Super-Nurture-al. Free Will-i-am Doctor Determinism The Reductionist-er! Fighting for all things natural. I believe that all behaviour is pre- determined by biological factors: hormones, genes & evolution. Doctor Determinism knows that all behaviour is determined by forces beyond human control. Determined to prove that behaviour is learned and influenced by social forces. I hunt down Nature-Man for the ultimate of battles: The Nature-Nurture Face Off. Fighting against the evil threat of Determinism, Free Will-i-am believes that we have the power to control our own behaviour. It’s all about the choice Flying through the skies on a mission to show that psychologists reduce complex behaviour down to over- simplified factors. He believes that behaviour should be looked at holistically.

10 A2 Psychology: IDA Superheroes APPROACHES Pavlov’s Power Puppy In the name of Behaviourism, Pavlov’s Power Puppy is here to show that all behaviour can be learned. Just ring that bell and I’ll be there ready to help! The Freud-ster In the name of the Psychodynamic approach… Motivated by his unconscious sexual desire, The Freud-ster wants to prove that our behaviour really is only the tip of the iceberg! Darwin’s Double In the name of Evolution, this Double Act are here to show that humans really did evolve from Apes! It’s all about the genes! In the name of Biology, Tommy Testosterone fights to prove that behaviour is underpinned by biological factors: brain structure, neurochemicals and genetics. Tommy Testosterone The Memory Marvel In the name of Cognitive Psychology, the Memory Marvel just goes to show that behaviour can be underpinned by cognitive processes. It’s all in the thinking!

11 What do you need to be able to do?  Write a description of circadian rhythms in about 100 words (4 marks) and 200 words (8 marks)  Identify 8 criticisms of this including one IDA topic (MRI – around 50 words each)  Write a description of ultradian and infradian rhythms in about 100 words each  Identify 4 criticisms of each of these including IDA (MRI)

12 Circadian Rhythms AO1AO2IDA Sleep-wake Cycle Circadian = 24 hours Cycle persists despite isolation from light Particpants not isolated from light in early research Demonstrated by Siffre and Aschoff & Wever External cues important too (Folkard at al) Cycle length varies in individuals Biological approach – suggests bodily rhythms can be explained by biological factors Deterministic – ignores the element of choice/free will humans have over their behaviour Core body temperature Lowest at 04.30; highest at Post-lunch dip, even without food Linked to cognitive abilities (Folkard et al) Evidence that change is caused by temp (Giesbrecht at al) Other research suggests link is spurious Hormones Cortisol lowest at midnight Melatonin and growth hormone highest at midnight.

13 Ultradian and Infradian Rhythms AO1AO2IDA Ultradian Less than one day Sleep stages = 1 st 4 – NREM, 5 th – REM BRAC = 90 mins within 24 hour rhythm REM does not equal dreaming BRAC important because it ensures biological processes work in unison Determinist (e.g. PM) but can change through willpower (Born et al) Real-world application - phototherapy Infradian Female menstrual cycle regulates ovulation Male shave 20 day cycle of body temp and alertness SAD caused by melatonin during winter months Menstrual cycle also subject to exogenous cues Some women suffer PMS SAD could also be consequence of disrupted circadian rhythms

14 Preparation – working together  In our next lesson, you will be writing two essays. 1. Describe and Evaluate research on circadian rhythms (8+16) 2. Describe and evaluate research on ultradian and infradian rhythms. (8+16)


16 Questions for today (25 mins each!) 1. Describe and Evaluate research on circadian rhythms (8+16) 2. Describe and evaluate research on ultradian and infradian rhythms. (8+16)


18 Connect  What might influence our natural rhythms?  Make a list of as many things you can think of and try to categorise them into internal (endogenous) and external (exogenous)

19 Objectives  Today you will  Learn about endogenous pacemakers  Learn about exogenous zeitgebers  Consider the implications of research done in this area  So that you can  Describe the role of endogenous pacemakers in biological rhythms  Describe the role of exogenous zeitgebers in biological rhythms  Evaluate the role of Eps/Ez’s in biological rhythms

20 Where is the body clock? Light travels from retina (back of the eye) along the optic nerve, and is picked up by the SCN

21 The ticking of the biological clock  The basis of circadian rhythm lies in interactions between certain proteins creating the ‘tick’ of the biological clock  It is an ingenious negative feedback loop  Darlington et al (1998) first discovered it in fruit flies but actual proteins vary from species to species  The protein mechanism is present in SCN (central oscillator) and other cells throughout the body (peripheral oscillators)  This explains why different functions have different rhythms

22 Body clock negative feedback loop CLK + BMAL1 PER CRY PER + CRY First two decrease This makes second two decrease also In the morning two proteins bind This stimulates production two new proteins These new proteins deactivate the first two CLOCK and BMAL1 begin to decrease As CLK and BMAL1 decrease, production of PER and CRY decreases also 24 hour period

23 Eps: The suprachiasmatic nucleus (SCN)  Tiny cluster of cells, in the hypothalamus, just above optic chiasm  Obtains info about light via optic nerve  If the sun rises earlier than day before, light resets the clock  There is one in each hemisphere, divided into two parts, dorsal and ventral.  Ventral is reset much more quickly, dorsal more resistant to being reset as it is less affected by light (Albus et al, 2005)

24 Eps: Pineal gland and melatonin  SCN sends signals to pineal gland telling it to increase melatonin at night  Melatonin induces sleep by inhibiting brain mechanisms responsible for alertness  In birds and reptiles this is just below the thin skull bone and so directly affected by light – light inhibts melatonin production.  Some lizards have a third ‘eye’ which sticks out of a small opening in the skull and receives info about light

25 Pineal eye of a Green Anole Lizard

26 Activity  Read over and complete the exercises on endogenous pacemakers in your booklet

27 Ezs: Resetting the biological clock  This process of resetting the biological clock is known as ENTRAINMENT.  The opposite of this is FREE-RUNNING  This is where the biological clock runs without any exogenous cues.

28 Ezs: Light  Dominant zeitgeber in humans  Light can reset the main pacemaker (SCN)  It can also reset other oscillators because the protein CRY (chryoptochrome) is light sensitive  This may explain why Campbell and Murphy (1998) found that if you shine a light on the back of participants knees, it shifts their circadian rhythms

29 Ezs: Social cues  Until recently it was thought these were the main EZ’s – we eat, go to bed, get up etc at socially determined times  It seemed our bodily rhythms were entrained by social convention, not internal biology.  Today we know light is the dominant EZ, and we also know that all parts of the body produce their own oscillating rhythms.  E.G. zeitgebers for heart and liver appear to be reset by eating, so light is not their primary zeitgeber. (Davidson, 2006)

30 Ezs: Temperature  Cold blooded animals have their circadian rhythms modified by external temperature  Buhr et al (2010)  Humans and other warm blooded animals’ body temperature cycle is governed by the circadian clock, and these temperature changes entrain other circadian rhythms.

31 Activity  Read over and complete the activities in your booklet on exogenous zeitgebers

32 Review Showdown  Where is the SCN?  What is its function?  Describe how the body clock works?  What other examples are there of endogenous pacemakers?  What three examples of exogenous zeitgebers have you learned?  One study that supports the influence of zeitgebers  One study that supports the influence of pacemakers  One IDA issue that can be applied to this topic

33 Homework  For next week (TUESDAY!)  Discuss the role of endogenous pacemakers and exogenous zeitgebers in circadian rhythms (8+16)  There are some documents on Moodle to help you with this.

34 Endogenous Pacemakers and Exogenous Zeitgebers AO1AO2IDA Endogenous Pacemakers SCN – main EP SCN contains protein mechanism Pineal gland controls melatonin secretion SCN evidence – ‘mutant’ hamsters Desynchronisation leads to symptoms similar to jet lag Evolutionary approach – SCN lesions in chipmunks (deCoursey et al) Non-human animal studies evaluated in terms of ethics and relevance. Exogenous Zeitgebers Light is dominant zeitgeber Social cues also important Biological rhythms can be entrained by temperature Artifical lighting may also reset biological clock Failure of biological clock leads to sleep- phase disorders Biological clock is really a blend of endogenous and exogenous factors You could also use studies from rhythms topics to add to your AO2: You just need to make sure you say why they are relevant!

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