biopsychology Flashcards
what is the nervous system made up of
the CNS and PNS
what are the nervous systems two main functions
to collect, process and respond to our environmental stimuli
to co-ordinate the working of organs and cells in the body
what is the CNS made up of, and what is it responsible for
the brain and spinal chord
the brain is the center of our concious awareness
the spinal chord is an a extention of the brain, passing messages between the brain, nerves and PNS, aswell as controlling refelx actions
what is the PNS
our network of nerves that runs all through the body
what is the PNS made up of
the somatic nervous system (SNS)
automatic nervous system (the ANS them splits further into the sympathetic and parasympathetic systems)
what does the somatic nervous system do
muscle movement (voluntary), recieves info from sensory receptors
what does the automatic nervous system do
controls vital functions like heart rate
the sympathetic is our fight/flight system
the parasympathetic is our rest/digest system
what does the endocrine system do
a slower, widespeard more poweful system based on our glands and the hormones they secrete
name some gland examples and the hormones they produce
adrenal gland - adrenaline - fight/flight response
thryoid gland - thyroxine - metabolism
ovaries - oestrogen - menstral cycle
testes - testosterone - sperm production
how do the endocrine system and ANS work together
they work in parrallel, for example, a stresor is percieved, the pituirary gland triggers the sympathetic state (fight/flight) in the ANS. adrenalie is released, the threat leaves and the parasympathetic state takes back over.
what neurons do we have
sensory, relay, motor
what does the sensory neuron do
they send sensory information to the brain, carrying messages from the PNS to the CNS. they have long dendrites and short axons and the cell body is found coming off the middle of the axon.
what does the motor neuron do
they carry signals from the CNS to our muscles and glands, so from the CNS to the PNS. they have short dendrites and long axons. the cell body is in the center of the dendrite
what do relay neurons do
they relay messages between sensory, motor and other relay neurons. they have short dendrites and short axons, they have no myelin sheath and the cell body is also in the center of the dendrite.
what are the features of a neuron
cell body/soma - holds the nucleus
nucleus - has the cells genetic information
axons - transfers the electrical impulse drom the cell body to the synapse
mylen sheath - acts as insulation, helps the impulse travel faster
dendrites - recieve the nerve impulse from neighbouring neurons
what is an action potential
when the neuron becomes positivelly charged an action potential ocours, causing an electrical impulse to travel down the axon to the next neuron.
what is the synapse, how do messages travel through?
a tiny gap between neurons, when a mesage travels down the neuron it is an electrical impulse. the message then changes to chemical to travel though the synapse before changing electrical again.
what are the all parts in a synapse
pre-synaptic neuron - the nerve end of the previous neuron, where the message is coming from
vessicles - holds neurotransmitters, rleases them into the synapse
receptor sites - where the neirotransmitters are recieved at the other end of the synapse
the post-synaptic neuron - the dentrites of the next neuron that recieves the message
what are excitory and inhibitory neurotransmitters
this is refering to the effect it has on the neighbouring neuron and how likely it is to fire
excitory example - adrenaline
inhibitory example - serotonin
what is summation
the excitory and inhibitory influences are summed up, if theres more inhibitory than excitory the less likely to fire
if theres more excitory, it is more likely to fire, the postsynaptic neuron becomes positively charged and an action potential occours
what does localisation of function mean
this refers to how spesific parts of the brain have spesific job roles
pre 19th cent it was thought the brain was holistic (working together as a whole)
what is a classic example of a localised function
the language centers are only in the left hemisphere
the brain is divided into 4 lobes, what are they
frontal lobe - at the front of the brain, higher cognitive functions
parietal lobe - at the top of the brain, sensory information
temporal lobe - on the side of the brain, language and auditory processing
occipital lobe - at the back of the brain, visual information
within the lobes theres 4 further areas, what are they?
motor area - frontal lobe, voluntary movement
somatosensory area - parietal lobe, sensory information
visual area - occipital lobe, processed contralaterally, right eye/left hem, left eye/right hem
auditory area - temporal lobe, speach based information
what is Broca’s area
linked with speech procuction, Broca’s patient ‘Tan’ could only say the word tan, post mortem showed damage to a part in his frontal lobe, now called brocas area
what is Wernicke’s area
linked with language comprihenstion, damage can lead to wernickes aphrasia, charicterised by speaking nonsense words, being incoherent but no issues saying the actual words
what is brain plasticity
the brains ability to change and adapt as a result of experience and learning
how does plasticity affect us in infancy
during infancy the brain grows synaptic connections rapidly, peaking at age 2-3
what is pruning in brain plasticity
as we age some synaptic connections go unused so theyre deleted
what is functional recovery
after the brain experiences a trauma, it tries to recover the best it can using healthy parts to take over tha damaged parts
what structural changes occour in functional recovery
axonal sprouting - growth of new nerve endings
denervation supersensitivity - axons with simular jobs take over
recruitment of homologous areas - simular areas on the other side of the brain take over
what is hemispheric lateralisation
when one half of the brain is responsible for one spesific function, like language is only in the left hemisphere
what is split brain surgery
when the corpus callosum is cut, preventing the hemispheres from being able to communicate with eachother. usually to help people with epilepsy control their seizures
how does visual information communicate with the hemispheres
contralaterally and ipsilaterally
contralateral: the right visual field is processed into the left hemisphere and vise versa
ipsilaterally: because thers crossover, its also processed in the same-side
what did Sperry study
a group of epileptics who had split brain surgery, he wanted to see what things they could/coundn’t do
Sperry tested three conditions to test their abilities, what were they all
describing what was seen when shown objects to each visual field
touch recognition
matching words to objects
what were the findings when his patients were describing what as seen
when an object was shown to their:
right visual field - they could easily describe what was seen
left visual field - said ‘nothing is there’ this is because theires no language centers in the right hemosphere (LVF=RH)
what were the findings of the touch recognition test
touch recognition: when shown an object to their LVF they could select the object using their left hand but not with their right hand
they couldnt say what they were selecting but their hand could recognise it
what happened in Sperrys matching words condition
matching words: ptps were shown two words that were seperated by a barrier so only one eye can see one word. eg key in the left and ring in the right. they would say ‘ring’ but would select a key in their hand
briefly evaluate sperrys research
he clearely shows and supports lateralised functions
however his control group didnt also have epilepsy - huge cofounding variable
what is a fMRI
a brain scan that detects blood oxygenation. presence of oxygen shows where activity is.
theyre virtually risk free with no radiation but are wildly expensive and have a 5ish second time delat (low temporal validity)
what is an EEG
a brain scan measuring electrical activity. patients have a cap with nodes that produces graphs reflecting brainwave patterns. theyre excellent for sleep studies and epilepsy diagnosis but provide very general information
what is an ERP
filters out extraneous brain activity from the original EEG recording, aiming to identify the brainwaves that are triggered by spesific events
what is a post mortem
post meaning after and mortem meaning death, this is when the brain is analysed after a patient, usually with a rare condition, has died. this was vital in early psych before brain scans but they cant show causation so scans are generally better now
what are biological rhythms
changes in body processes or behaviours that repeat regularly in a cycle
eg. circadian, ultradian and infradian rhythms
how long does a circadian rhythm last
24 hours, such as the sleep/wake cycle
what are infradian rhythms
cycles that occour less than once in 24 hours, like the menstral cycle (28 days)
what is an example of an infradian rhythm
the menstral cycle
SAD - seasonal affective disorder
what happens in the menstrual cycle
lasting 28 days on avg but can range from 24-35 days
rising levels of oestrogen cause the ovary to release an egg, progesterone then helps the wombs lining to grow thicker, if pregnancy doesnt occour the egg is absorbed and the lining comes away
what happens for those with seasonal affective disorder
depressive symptoms in winter but not summer, refered to as a circuanual rhythm because it takes a year to complete. caused by the pineal gland (endogenous pacemaker) releasing more melotonin (sleepy) for longer because its dark all the time, this has a knock on effect for serotonin production being reduced
what research has been done into synchronising the menstrual cycle
influence of pheromones can affect our cycle. researchers studied a group of women with a history of irregular periods, they then gathered pheromone samples from some of them, on different days in their cycle. the sample pads were taken from their armpits, treated with alcohol and frozen then rubbed on the upper lip of the other women. (on the corrosponding days of their cycle so day1+pad1, then 2 etc)
68% of women experienced changes, beinging their cycles closer to their matched pair.
what are two strengths of research into infradian rhythms
it makes evolutionary sense for womens cycles to synchronise, if women are getting pregnant at the same time then babies can be cared for as a collective, and if one mother dies the other mothers can breastfeed her baby and bring baby up with the others.
theres also real world application ofr SAD, light therapy is the most effective treatment, shown to reduce symptoms in 80% of people, this is also a safer alternitive to drug therapy.
what are ultradian rhythms
cycles that occour more than once in 24 hours such as the stages of sleep
what stages of sleep are there
sleep stages happen every 90 minutes throughout the night, there are 5 stages
1-2. light sleep, easy to wake, high frequency alpha waves
3-4. deep sleep, delta waves that have lower frequency, people are harder to wake
5. REM sleep, body is paralised but the brain resembles that of an awake brain, dreams are most likely, jolty activity (REM)
what is one strength and weakness of ultradian rhythms
sleep studies are done in very controlled conditions in labs instead of at home so they can be connected to the scanners, this means theres no extrenuous variables like noise and temperature
however this is an artificial situation, the discomfort of not being at home could also be an issue to the validity and may not represent ordinary sleep
theres also a significant variation in peoples sleep cycles in terms of duration suggesting that it may have a biological basis - defining ‘normal’ sleep is difficult
what are biological clocks goverend by
our internal body clocks (endogenous pacemakers) and changes in our environment (exogenous zeitgebers)
what is an endogenous pacemaker
an internal body clock, regulating our biological cycles
whats an exogenous zeitgeber
an external factor affecting our biological clocks (eg. daylight)
what is the superchaismatic nucleus (SCN)
a bundle of nerve cells that maintains our circadian rhythms thats sat by the optic chaism recieving information about light that regulates our body clock.
what animal studies demonstrate the SCN in action
SCN connections were destroyed in chipmonks, they completely lost their sleep/wake cycle resulting in alot of them dying to preditors because they were awake when they werent supposed to be
extra: mutant hamsters were bred with 20h cycles then transplanted their SCN tissue into normal hamsters and their cycles changed from 24 to 20
whats are two examples of an exogenous zeitgeber
light - light resets our SCN which regulates our biological clock, so if our body clock is running slow, the light will shift the clock ahead
social cues - newborn babies have a very unregulated sleep cycle, circadian rythms usually form around 6 weeks and by 16 weeks the parents have fully imposed their schedules
this can also be seen in jet lag, where our rhythms ajust to the time of the new country were in
what is the role of the pineal gland and melotonin as an endogenous pacemaker
the SCN passes light information to the pineal gland. during the night the pineal gland produces melatonin (chemical inducing sleep)
what is one strength and weakness of exogenous zeitgebers
what is one strength and weakness of research intoendogenous pacemakers
what did siffre (seef) do in his cave study
he wanted to see what happened when biological rhythms are free of exogenous zeitgebers. He would spend extended periods on caves (no lnatural light or sounds) to see how they would settle. He found that his rhythm lasted slightly longer, around 25 hours. when he emerged 2 months later he believed it to be mid-august when it was mid-september
what other research, simular to siffre’s cave study has been done
participants spent 2 weeks in a WW2 bunker (no light) and all but one (29h) settled to a 24-25 sleep wake cycle
as a result it was suggested that our sleep/wake settles at a little over 24 hours but is entrained by exogenous zeitgebers
why is research into our circadian rhythms important
provides understanding of the consequenses to disrupting our cycles, in night shift workers tend to have reduced concentration at 6am so accidents are more likely to happen
theres also a relationship between shift work and poor health, being more likely to develop heard disease than typical work patterns - this shows real world and economic implications
how do circadian rhythms affect medications
research into our rhythms has lead to improving medical treatments, because rhythms govern eg heart rate, digestion, hormones, some medications work better when taken at certain times. When used for preventing heart attacks, asprin is most effective when taken at night
what benifits for schools does research into rhythms have
it was proposed that we should change the school day to start later because teenage sleep wake cycles mean that theyre drowsier in the mornings meaning their could be acedemic benifits.
however this isnt practical for the rest of the world, for parents and teachers etc who would be disrupted and the amount of extracurricular activity would have to be reduced
