Biopyschology Flashcards
(83 cards)
1
Q
What is the CNS and its function
A
It is something made up of the spinal chord and brain, and has two main functions. One is on control behaviour, and other is to regulate the body’s physiological processes. (Does this by reecevive info from sensory receptors like ears and eyes and sending messages to muscles and glands)
2
Q
Brains 4 main areas
A
Cerebrum - largest area of brain that has 4 lobes split through the middle, creating left/right hemisphere
Cerebellum - motor skills, balance and coordinating muscles to allow precise movements
Diencephalon - contains the thalamus (regulates consciousness, sleep) and hypothalamus (regulates body temp, stress response, hunger and thirst)
Brain stem - regulates breathing and heart rate
3
Q
What is the PNS and function
A
The PNS consists of the nervious system throughout the body (eg, not brain/spinal chord). It transmits messages via neurons to and from CNS.
4
Q
Two divisions of the PNS
A
- Somatic nervious system
- Autonomic nervous system
5
Q
What’s the somatic nervious system
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It controls all voluntary movements and is under conscious control. Connects senses with CNS and has sensory and motor pathways. Also controls skeletal muscles and controlled by motor cortex
6
Q
What is the autonomic nervous system (ANS)
A
The ANS is involuntary and only has motor pathways. Controls smooth muscles, internal organs and glands and controlled by the brain stem.
7
Q
What is the sympathetic nervous stem (SNS)
A
This is activated due to stress = increase heart and breathing rate, digestion stops, salivation reduces, pupils dilate and flow of blood diverted from the surface on the skin.
8
Q
What’s the parasympathetic nervous system (PNS)
A
Activated when we are relaxed and conserving energy. Heart and breathing rate reduces, digestion begins, salivation increases and pupils constrict.
9
Q
How is the overall nervous system split
A
10
Q
What are neurons
A
Specialised nerve cells that move electrical impulses to and from the CNS
11
Q
Functions of each part of a neurons
A
- Cell body - controls centre of nuclues
- Nuclues - contains genetic material
- Dendrites - receives electrical impulses (action potential) from sensory receptors
- Axon - long fibre carrying the impulses along the neuron from the cell body to the axon terminal
- Myelin Sheath - insulates axon and speeds up transmission of electrical impulse
- Schwann cells - make up the myelin sheath
- Nodes of ranvier - gapes in myelin sheath that further speed up impulses
12
Q
Neurone diagram
A
13
Q
Sensory neuron and their function
A
Carry electrical impulses from sensory receptors to the CNS via the peripheral nervous system. The convert info from receptors to electrical impulses which reach brain and are converted into sensations like pain, heat etc. this also body to react in accordance.
Some go directly to spinal chord In order to bypass the brain and trigger a direct reflex action in response to danger. 0.7->0.2s in time to react by bypassing brain
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Q
Motor neurone and function
A
Located within the CNS, while projecting their axons outside it, they send the impulses to the muscles and glands via their axons.
When the neuron are stimulated, they release neurotransmitters that bind to receptors on muscles to trigger a response, leading to movements
15
Q
Relay neuron and function
A
Found within the CMS, they connect sensory and motor neurons.
16
Q
What is an action potential
A
When neurons transmit electrical impulses.
17
Q
What is synaptic transmission?
A
Neurons transmit electrical impulses between the presynaptic neuron and postsynaptic neuron. These electrical impulses, known as action potentials, reach the presynaptic terminal and triggers the release of neurotransmitters from sacks on the presynaptic membrane, known as vesicles. These neurotransmitters will then diffuse across the synaptic cleft, and then binds to a postsynaptic receptor site. This neurotransmitter is then taken back by the vesicles on the presynaptic neuron where they are stored for later release.
18
Q
What is an excitatory neurotransmitter?
A
Excitatory neurotransmitters cause an electrical charge in the membrane of the post synaptic neuron, resulting in excitatory postsynaptic, potential, meaning the postsynaptic neuron is more likely to firing an impulse
19
Q
What is an inhibitory neurotransmitter?
A
An inhibitory neurotransmitter will cause an inhibitory post-synaptic potential, therefore, making it less likely that the neuron will fire an impulse.
20
Q
How is the likelihood that a neuron firing an impulse determined?
A
A neuron can receive both excitatory-postsynaptic potential or inhibitory- postsynaptic potential.
The likelihood of a neuron firing an impulse is determined by adding up the excitatory and inhibitory synaptic input.
The net result, determines whether or not it will fire and impulse.
21
Q
What is summation?
A
Summation is the net result of the calculation from adding of the excitatory and inhibitory Synaptic input. This determines whether or not the new one or fire an impulse. If the net effect is inhibitory than you and won’t fire if it’s excitatory, it will.
22
Q
What are psychoactive drugs?
A
Psychoactive drugs and medication affects brain function to alter perception mood or behaviour. And they work by affecting (either increasing or inhibiting) the transmission of neurotransmitters across a synapse.
23
Q
How does pain medication mimic the effects of inhibitory neurotransmitters
A
Due to summation if inhibitory neurotransmitters are higher than excitatory ones, they can inhibit an action potential from occurring. Therefore, pain medications would decrease the overall activity and reduce brain activity may be leading to less pain.
24
Q
What is the pituitary gland and function.
A
Is the gland located in the brain and it produces hormones whose primary function is to influence the release of other hormones, and is controlled by the hypothalamus.
The hypothalamus receives information from many sources about the functions of the body, then sends a signal to the pituitary gland in the form of a releasing hormone. This causes the pituitary gland to send a stimulating hormone in the bloodstream to tell a target gland to release a specific hormone. Then, once the specific hormones in the bloodstream, the hypothalamus shuts down the production of the releasing hormone, and the pituitary gland shutdowns the secretion of the stimulating hormone.
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What are the divisions of the pituitary gland?
1. The anterior pituitary gland releases the hormone ACTH which regulates levels of cortisol.
2. The posterior pituitary gland is responsible for releasing a hormone oxytocin, which is important for mother and infant bonding.
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Adrenal cortex and function
This is the outer section of the adrenal gland. It produces cortisol which is produced in high amounts when someone is experiencing chronic stress it’s also responsible for the cardiovascular system. For instance it will increase blood pressure and cause blood vessels to constrict.
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Adrenal medulla and its function
This is the intersection of the adrenal gland which produces adrenaline which is needed for a fight or flight response. When we are stressed. This can do things such as increase heart rate, dilate, pupils and stop digestion.
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What is the sympathomdullary pathway
The sympathetic nervous system is triggered by the hypothalamus, causing it to send a signal to our adrenal medulla, which then releases adrenaline, which then braces our body for a certain threat. For example, it may do this by increasing blood supply, and therefore oxygen to the muscles needed for physical action.
Once the threat has passed, the parasympathetic nervous system dampens down the stress response by slowing down the heartbeat, and reducing blood pressure.
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Evaluation of fight or flight response (2+ 3-)
1. It makes sense from a Psychologically evolutionary point of view, as it would’ve helped an individual to survive by fighting or fleeing a threat.
2. Studies support the claim that adrenaline is essential in preparing the body for stress. People who have malfunctioning adrenal glands don’t have normal fight or flight response to stress.
3. Gray (1998) states the first reaction to stress isn’t fight or flight but freeze, which involves the person stopping, looking and listening and being hyper vigilant to danger.
4. Taylor (2000) found females seem to ‘tend and befriend’ in times of stress which refers to the protection of offspring and seeking out social groups for mutual defence. This may be as women have the hormone oxytocin, which means they are more likely to stay in protect their offspring.
5. Van Dawans (2012) find a males also tend and befriend. During the terrorist attacks on the 11th of September 2001 both men and women seem to tend and befriend as they try to contact their love ones at times of stress.
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What is localisation of function?
This refers to the principle that functions, such as hearing and memory, have specific locations in the brain. Research shows that some functions are more localised than others.
The motor and somatosensory functions are highly localised to particular areas of the cortex while other functions are more widely distributed, such as the language system, which uses various parts of the brain.
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What are visual centres and where are they located?
The visual cortex processes information like colour and shape and it is in the occipital lobe of both hemispheres of the brain.
Visual processing starts in the retina were light enters and strikes the photoreceptors. Nerve impulses from the retina or transmitted to the brain via the optic nerve. Most of the terminate in the thalamus, which acts as a relay station, passing this info onto the visual cortex.
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What is the auditory centres?
The auditory cortex processes information like pitch and volume. It lies within the temporal lobe in both hemispheres of the brain.
Auditory pathway begins in the cochlea of the inner ear with soundwaves are converted to nerve impulses which travel via the auditory nerve to the auditory cortex. Most decoding occurs in the brain stem, and the thalamus carries on further processing before impulses reach the auditory cortex.
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Motor cortex and its function
Responsible for voluntary movement and is located in the frontal lobe of both hemispheres different parts of motor cortex control different parts of the body.
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What can happen if the motor cortex is damaged
Damage to this area can cause a lot of muscle function and paralysis in one or both sides of the body
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What is the somatosensory cortex?
It is responsible for processing sensations like pain and pressure and is located in the parietal lobe of both hemispheres in the brain
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What two areas are responsible for language
1. Broca’s area
2. Wernickes Area
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Broca’s area
This area is named after Paul Broca, who treated patients who had difficulty producing speech. He found that they had lesions on the left hemisphere of the frontal lobe.
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Damage to Broca’s area
Damage to this area causes expressive aphasia. This disorder affects language production, but not understanding. Speech lacks fluency, and patients have difficulty with certain words that help with sentences.
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Wernickes area
This area is in the left hemisphere of the temporal lobe. Karl Warnicke found patients with a lesion to this area could speak, but what unable to understand language. He concluded that this area is responsible for the processing of spoken language. It is connected to the Brocas area by neural loop.
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Damage to Wernickes area
Damage can cause receptive aphasia, which leads to an impaired ability to understand language
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Evaluation of localisation of function (5-)
1. Some functions and more localised and others, like motor and somatosensory functions are highly localised to specific areas of the cortex, but higher functions (personality and consciousness) are much more widely distributed. Functions like language are too complex to be assigned to jus t one area and instead involve networks of brain regions.
2. Equipoteniality Theory introduced by Lashley (1930) states higher mental functions aren’t localised. Also claims that intact areas of the cortex take over responsibility for specific cognitive function following injury to the area of normal responsibility.
3. Dronkers at al. (2007) re-examine, preserve brains of two brocas patients. MRI scans found several areas of brain that had been damaged. Usually, lesions to the area caused temporary speech disruptions and not severe language disruptions. Therefore language is a more widely distributed and therefore less localised than originally thought.
4. Dejerine (1982) reported a patient who couldn’t read because of damage to the visual cortex and Wernickes area. Thus it may be how brain areas communicate with each other is more important, the specific brain regions.
5. Bavelier et al. (1997) found that there is individual differences in which brain areas are responsible for certain functions. Found a different brain areas are activated when a person is engaged in reading and found activity in right temporal lobe, left frontal lobe and occipital lobe. Therefore, meaning that the function of reading doesn’t have a specific location within the brain and this could potentially apply to other functions.
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What is hemispheric lateralisation?
It refers to the notion that certain functions are principally governed by one side of the brain. For example, research has demonstrated most peoples language centres are lateralalised to the left hemisphere. 
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What is the right hemisphere of the brain responsible for?
The right hemisphere is dominant for Visuo-spatial function of facial recognition. It also responsible for the left-hand side of the body.
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What is the left-hand side of the brain responsible for?
The left hemisphere is responsible for the right hand side of a body free sample. If a patient has experience right-sided paralysis. This means there is lateralised damage to the left hemisphere.
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How do you the two brain hemispheres work in tandem?
The two hemispheres are connected by a bundle of nerves fibres called corpus callosum, which allows information to be communicated between the two. Many researchers suggest the two hemispheres work simultaneously to complete tasks as part of a highly integrated system.
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Evaluation of hemispheric lateralisation (2+ 3-)
1. One advantage is that it makes sense for an evolutionary standpoint. It increases new processing capacity which is adaptive by using one hemisphere to engage in particular task to leave the other one free to engage another one. Rogers at al (2004) found hemispheric lateralisation in chickens is associated with an ability to perform two task simultaneously.
2. Patients who have extensive damage to the left hemisphere can experience global aphasia, therefore suggesting that language is lateralised to the left hemisphere.
3. Szaflarski (2006) suggested lateralisation patterns shift with age, with most tasks becoming less lateralised in healthy adulthood.
4. JW (a split-brain patient) develop the capacity to speak, using his right hemisphere with the result that they could speak about info shown in either the left visual field or the right visual field. Therefore it would appear language isn’t lateralised entirely to the left hemisphere.
5. Daneli (2013) suggested if one hemispheres damaged, undamaged regions of the other hemisphere can compensate. They reported the case of EB who was a 17-year-old Italian boy who had the majority of his left hemisphere removed at a young age. His language appeared almost normal in every day life in terms of vocab and grammar. However, systematic testing revealed, subtle, grammatical problems, as well as poorer than normal scores on picture, naming a reading of loan words (adopted from other languages like café). Thus language function to be largely preserved after the removal of the left hemisphere in childhood, but the right hemisphere cannot provide a perfect mastery of each language component, but can still compensate for it.
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Split brain research study (Sperry and Gazzaniga 1968)
They investigated split brain patients. Info shown from the left visual field going into the right hemisphere and vice versa, because in split brain patients the corpus callosum has been severed there is no way for the information to go from one hemisphere to the other.
In the experiment, patient were asked to stare in the centre of the screen and then info is presented in either the left or right visual field. They are then asked to make responses with either the left-hand (right-hemi) or right hand (left-hemi), or verbally (left-hemi) without seeing what their hands were doing.
For example, they may have seen an image of a dog in the right visual field and therefore answer dog because the info would have gone into the left hemisphere where the language centres are. But, if a picture of a cat is shown in the left visual field and they ask what they are saying they will not be able to say because the information has gone into the right hemisphere which has no language centres. But on the other hand, they may be able to draw a picture of a cat with the left hand because the right hemisphere controls this hand.
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Evaluation of split brain research (2+ 3-)
1. Has enabled discoveries of hemispheric lateralisation.
2. They are highly controlled and scientific experiments, therefore leading to objective results.
3. Patients have often had drug therapy for the epilepsy for much longer than others which could affect the way the brain works. This means finding of split brain patients can’t be generalised the target population.
4. Very studies have as few as three participants, again, making it hard for the findings to be generalised to everyone.
5. The data collected from the experiment is very artificial. This is because in the real world, a restricted corpus callosum can be compensated for by unrestricted use of both visual fields. Therefore, the research lacks ecological validity.
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What is brain plasticity
Refers to brain ability to change and adapt as a result of experience it allows the brain to cope better with indirect effects of brain damage like swelling, or the damage resulting from inadequate blood supply due to a stroke
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Plasticity - life experience
Nerve pathways frequently develop stronger connections, and those rarely used die. By developing new connections and reducing week ones we cause the brain to adapt to a changing environment.
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Plasticity - video games
Kuhn et al. (2014) compared a control group to group have been given video game training for at least 30 minutes a day for two months found that playing video games.
This caused a significant increase in grey matter in the visual cortex, hippocampus and cerebellum. It also resulted in new synaptic connections in brain areas involved in spatial navigation, strategic planning, working memory and motor performance.
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Plasticity - meditation
Davidson et al. (2004) compare to a practitioners of Tibetan meditation with 10 students who had no previous meditation experience. An EEG picked up great activity in the monks, even before they started meditation, suggesting gamma waves, coordinate neural activity.
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Evaluation of plasticity (2+)
1. Kempermann et al. (1998) found more neurons in rat brains in complex environments, compared to household basic cages increase. The neurons has most prominent in the hippocampus, which is involved in the forming of new long-term memories and ability to navigate.
2. Maguire et al. (2000) measured Greymatter in the brains of people in London. Taxi drivers, using MRI, found to have bugger hippocampus than a control group, and this is positively correlated with the amount of time they spent as taxi drivers (extent of life experience)
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What is functional recovery?
It is a form of plasticity. Following damage caused by trauma brains can re-distribute or transfer functions usually performed by damaged areas to other undamaged ones, and the brain is able to carry out plasticity and functional recovery at any ages
And research suggests women recover from a brain injury quicker than men do.
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Functional recovery - What is neural reorganisation?
The transfer of functions from damaged areas to undamaged ones can occur, which is known as neural reorganisation
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Functional recovery - neural regeneration
When there’s growth of new neurons and connections to axons in dendrites to compensate for damaged areas .
Axon sprouting occurs, where nerve endings grow and connect with other undamaged nerve cells form new neural pathways
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Why may physiotherapy be important in the recovery of our brain
Spontaneous recovery from the brain injury tends to slow down after a number of weeks of physiotherapy, so it may be useful to maintain improvement in functioning,
For example, techniques like movement therapy and electrical stimulation to counter the deficit in motor and cognitive functioning.
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Evaluation of functional recovery (2+)
1. Phantom limb syndrome can be used evidence as neural reorganisation. PLS is the continued experience of sensation in a missing limb and they are often unpleasant, and even painful. PLS caused by neural reorganisation in the somatosensory cortex, which may occur due to limb loss (Ramachandran and Hirstein 1998)
2. Huber and Wisel (1963) sewed one eye of a kitten shut, and analyse the brains, cortical response. Found out the visual cortex for the shut eye wasn’t ideal (as expected) and continued to process info from the open eye. Further evidence that brain areas can re-organise themselves and adapt functions.
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What is a post-mortem?
In order to study a person who displays interesting behaviour, psychologists may look for abnormality in the brain. When someone dies, post-mortem studies have found a link between brain abnorma and psychiatric disorders.
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Evaluation of using post-mortems (1+ 2-)
1. Post-mortem studies, allow for more detailed examination of anatomical and neurochemical aspects of the brain. They have enabled researchers to examine deeper regions like Hippocampus and hypothalamus.
2. Studies may lack validity because people die in variety of circumstances and at varying stages of diseases. Also length of time between death and post-mortem and drug treatments can all affect the brain.
3. Studies have very small sample sizes as special permission is needed to be granted. Means the sample panel to be representative of target population, so it’s hard to generalise findings.
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Functional magnetic resonance imaging (fMRI)
fMRI provides indirect measure of neural activity. Does this by using magnetic fields and radio waves to monitor blood flow in the brain. Measures changes of energy released by haemoglobin, reflecting the activity in the brain, which gives a moving picture of the brain. Then activity in the region of interest can be compared during a baseline task doing a specific activity.
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Evaluation of fMRI (2+ 2-)
1. They catch dynamic brain activity as opposed to a post-mortem, which purely shows the physiology of the brain.
2. They have a good spatial resolution which refers to the smallest feature that measurement can detect.
3. The interpretation of it is complex and has affected by poor temporal resolution, biased interpretation, and by the baseline task used
4. Research is expensive leading to reduced sample sizes which negatively impacts the validity of the research.
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What is an Electroencephalogram (EEG)
An EEG measures general neural activity in the brain usually linked to states like sleep and arousal. Electrodes are placed on the scalp and detect neural activity. electrical signals from the different electrodes are graft over a period of time.
The resulting representation is called an EEG pattern. This pattern of patients with epilepsy showed spikes of electrical activity. These patterns of those with brain injury show a slowing of electrical activity.
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Evaluation of EEG (2+ 1-)
1. It’s useful in clinical diagnosis. For instance, I can record the neural activity associated with epilepsy so doctors can confirm the person experiencing seizures.
2. They are cheaper than fMRI so used more widely in research
3. They have poor spatial resolution.
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What are event related potentials?
It’s the measured brain response that is the direct result of a specific sensory, cognitive, or motor event.
Electrodes are placed on the scalp and directly measure neural activity in response to a specific stimulus introduced by researcher. Event related potential is difficult to pick out from all other electrical activity being generated from the brain. To establish a specific response to target stimulus, it requires many presentations of the stimulus and the responses are averaged together.
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Evaluation of the event related potentials (3+ 2-)
1. They can measure the processing of a stimulus, even in absence of a behavioural response. Thus it’s possible to measure ‘covertly’ the processing of a stimulus.
2. They are cheaper than fMRI so can be used more widely in research
3. Have a good temporal resolution, unlike fMRI’s
4. They have poor spatial resolution, unlike fMRI’s.
5. Only strong enough voltage changes generated across scalp arer recordable. It’s important electrical energy occurring deep in the brain isn’t recorded and generation of ERPs tends to be restricted to the neocortex.
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Circadian rhythms
Cycles at last 24 hours, that almost all organisms possess. They optimise an organisms, physiology and behaviour to best cope with the demands of the day and night cycle.
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What is suprachiasmatic nuclei (SCN)
They drive circadian rhythms in hypothalamus. This pacemaker (by controlling rate at which something occurs) must constantly be reset so bodies are in synchrony with outside world.
Natural light provides the input to the system, setting SCN to the correct time in a process called photo-entrainment. SCN uses this info, to coordinate activities of circadian rhythms throughout the body.
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Sleep-wake cycle
Light or darkness or external signals that determine when we feel we need to sleep and wake up rhythm, dips and rice. The different times a day so the strongest sleep drivers occur between 2am - 4 am and 1pm - 3 pm.
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The role of melatonin in sleep-wake cycle
It’s released from the pineal gland at its peak during the hours of darkness. Did induces sleep by inhibiting the neural mechanisms that promote wakefulness.
In turn light, suppresses the production of melatonin .
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Evaluation of circadian rhythms (1+ 4-)
1. A practical application of it is Chronotherapeutics. Timing that patient takes medication is pivotal for treatment success. It’s essential that the right concentration of drug is released in the target area of the body at a specific time. Eg risk of heart attack is greatest during early morning. Thus medication have been developed to be taken before someone goes to sleep that aren’t released until this vulnerable time period of 6 am.
1. Research has not isolated people from artificial lights because believe only natural light affected circadian rhythms. But recent research suggest this is a true. Cziesler et al (1999) altered people’s circadian rhythms down 22 hours and up to 28 hours by using artificial light alone
2. Individual differences in length of circadian rhythms. One study found cycles can vary from 13 to 165 hours.
3. Another individual differences in the rhythms is when they reach the peak. Morning people prefer to rise early and go to bed early. Where is evening people prefer to do the opposite.
4. Studies of people living in Artic regions were Sun doesn’t set in summer month, show normal sleeping pattern despite prolonged light exposure. Suggests there is occasions where the exogenous zeitgeber of light may have very little bearing on internal biological rhythms.
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Ultradian rhythms
Ultradian rhythms span a period of less than 24 hours, for example, the five stages of sleep. Humans sleep follows pattern, alternating between rapid eye movement (REM) sleep (stage 5), and non-rapid eye movement (NREM) sleep (consist of stage 1,2,3,4). The cycle repeats itself every 90 minutes.
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Kleitman (1969) study (BRAC)
Kleitman, referred to the 90 minute cycle found during sleep as the Basic Rest Actitvty Cyle (BRAC). Suggested that this 90 minute cycle continues when we are awake during the day. Instead of moving through sleep stages, we progressively move from a state of alertness into a state of physiological fatigue.
Studies suggest humans minds can focus for around 90 minutes
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Evaluation of Ultradian rhythms (1+ 1-)
1. Ericsson et al (2006) found support for Ultradian rhythms. Studied a group of elite violinists and found among the group practice sessions were limited to 90 minutes at the time. They frequently napped to recover from practice, with the best violinists napping more. The pattern even fitted other peoples orders, chess players and writers fitting the BRAC pattern.
2. Tucker et al (2007) suggest there’s individual differences in the rhythms which are biologically determined and possibly genetic in origin. Participants were studied over 11 consecutive days and nights in a lab and assessed sleep duration, time taken to fall asleep, and the amount of time in each stage. Found differences in all of the characteristics.
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Infradian rhythms
Rhythm spanning longer than 24 hours. That may last weeks, months or years, such as the menstrual cycle.
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Evaluation of infradian rhythms (1+ 1-)
1. Penton-Voak (1999) showed how they can affect behaviour. He found that women expressed a preference for feminised male faces when choosing a partner for long-term relationships, but had preference for masculine ones during ovulation.
2. The menstrual cycle isn’t governed by infradian rhythms only. For example, when many women of childbearing age live together, and don’t take oral contraceptives, the menstrual cycle synchronise. In a study, samples of sweat were collected from a group of women and rubbed onto the upper lip of another group of women, leading to the menstrual cycle is becoming synchronised, suggesting that synchronisation is affected by pheromones, rather than infradian rhythms.
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How are our biological rhythms kept fine-tuned
We have endogenous pacemakers (internal biological rhythms) and exogenous zeitgebers (external factors like light) with reset our biological rhythms every day
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Evaluation of endogenous pacemakers (1+ 1-)
1. Folkard (1996) studied a uni student, Kate, Aldcroft, who spent 25 days in lab. She had no access to exogenous zeitgebers of light to reset the SCN, but at the end of 25 days, her core temperature rhythm was still at 24 hours, indicating we don’t need the exogenous zeitgebers of light to maintain our internal biological rhythms
2. Kate Aldcroft’s sleep, wake cycle, extended to 30 hours with period asleep as long as 16, suggesting we do need the exogenous zeitgebers of light to maintain our typical internal biological rhythms, unlike Kate
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Exogenous zeitgebers
Refers to anything whose origins are outside of the organism, such as environmental events that are responsible for maintaining the biological clock, like light.
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How do exogenous zeitgebers function
Receptors in the SCN are sensitive to changes in light during the day, and use this info, to synchronise the activity of the bodies, organs and glands.
Light resets the internal biological clock every day, keeping it on 24 hour cycle. Protein in the retina of the eye called melanopsin is sensitive to natural light, and it’s crucial in the system.
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What may happen when people travel to a different country or move to a nightshift
The endogenous pacemakers try to impose there in the rhythm of sleep, but this is now out of synchrony with the exodegenous zeitgeber of light.
Thus, out of sync biological rhythms leads to disrupted sleep patterns, increased anxiety and decrease alertness and vigilance.
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Evaluation of exogenous zeitgebers (2+ 1-)
1. Majority of blind people who still have light perception have normal circadian rhythms, but people without light perception do not. Shows the vital role that zeitgebers of light levels play in maintaining our internal biological rhythms.
2. Burgess et al (2003) found that exposure to bright light prior to an east-west flight, decreased the time needed to adjust circadian rhythm to local time
3. Individuals who live in Antarctica regions were Sun doesn’t set in summer month still showed normal sleeping patterns despite prolonged light exposure. Suggest there is occasions where the Exogenous zeitgeber of light may have a small bearing on internal biological rhythms.
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What is reuptake
Process where neurotransmitters get reabsorbed back into the presynaptic neuron they came from
