Biopsych Flashcards
what does the nervous system divide up into
Central nervous sytem- brain and spinal cord
Peripheral nervous system- somatic and autonomic
nerve cells that carry messages around the body
function of the brain
takes information from senses, interprets it and acts on it
the brain is the centre of all conscious awareness and is involved in all physiological processes
function of the spinal cord
passes messages to and from the brain and connects nerves to the peripheral nervous system
also responsible for reflex actions
function of the somatic nervous system
recives info from sesnsory receptors and sned this information to the CNS
relays info to motor neurons
control muscle movement
function of the autonomic nervous system
nerves of ANS connect to the CNS to the internal organs
plays important role in homeostasis
control invoulantary functions, works automatically
divided into sympathetic and parasympathetic nervous system
what are neurons
nerve cells that process and transmit messages through electrical and chemical signals
structure of neurons
cells body- includes and neucleus and contains angentic code
dendrites- at the end of the neurone, receive electrical impulses from neighbouring neurons and carry information towards the cell body
axon-transfers electrical impulse signals from the cell body to the neighbouring neurons
myelin sheaf- cover the axon and act like insulation to keep electrical signals inside the cell, allowing them to move quicker
functions of a neurone
receive, respond and send messages
messages sent by neurons are called action potentials
the function of sensory neurone
carry messages from the 5 senses to the CNS
convert information from the sensory receptors into nerve impulses passed to brain or spinal cord
long dendrites short axons
the function of the relay neurone
connects sensory neurone to motor neurone or other really neurones
allows neurones to communicate witheachother
short dendrites and short axons
the function of the motor neurone
connects the CNS to muscles and glands
releases neurotransmitters that bind to receptor sites on the muscles and trigger a response that leads to muscle movement
short dendrites and long axons
explain the process of synaptic transmission
action potential reaches the end of a neurone
the pre-synaptic neurone releases neurotransmitters from synaptic vesicles into the synaptic gap
the neurotransmitters diffuse across the synapse to the postsynaptic receptor sites on the postsynaptic receptors
they then either fire or not
neurotransmitters are then reuptaken by the presynaptic neuron, where they are stored ready for later use
quicker the neurotransmitter is taken up the less effective it is
explain excitation and EPSP
if a neuron becomes positively charged it is more likely to fire
an excitatory neurotransmitter binding with the postsynaptic neurotrnasmitter results in an excitatory synaptic potential (EPSP), the postsynaptic cell is more likely to fire
explain inhibition and IPSP
a neuron that is negatively charged is less likely to fire
an inhibitory neurotransmitter binding with postsynaptic neurotransmitter results in an inhibitory synaptic potential (IPSP), meaning postsynaptic receptor is less likely to fire
explain the decision wether to fire or not
if the number of excitatory neurotransmitters is the same as the number of inhibitory neurotransmitters they cancel themselves out and do not fire
if excitatroy synapses are ore active, cells fire at a high rate
if inhibitory synapses are active, cells fire at a lower rate or not at all
what is the function of the endorcrine system
secretes hormones in the body from the glands which are needed to regulate bodily functions and provide a chemical system of communication via the bloodstream
works alongside the nervous system to control vital functions in the body using the sympathetic and parasympathetic nervous sytem
what are hormones
act as chemical messengers in the body telling it to perform physical and mental functions.
transmit info via the bloodstream
alter the probability of behaviour occurring
role of the hypothalamus
controls the release of 8 major hormones by the pituitary gland
role of the pituitary gland
master gland, controls the release of hormones from all other glands in the endocrine system
role of the adrenal gland
control the release of adrenaline and noradrenaline into the blood stream as a response to fight or flight causing physiological changes
role of the thyroid
plays major role in metabolism, growth and maturation
role of the ovaries
two small organs for child birth, secretes the female sex hormone
role of the testes
two small gland which produce sperm and the hormone testosterone
explain the fight or flight response
1.a stressor is perceived
2.the amygdala sends a message to the hypothalamus
the hypothalamus activates the sympathomeduallary pathway (SAM pathway)
- the sympathetic nervous system stimulates the adrenal medulla
- the adrenal medulla secretes the hormone adrenaline and noradrenaline into the blood stream
- adrenaline causes a number of physiological changes to prepare body for fight of flight
- once the stress is over the parasympathetic nervous system is activated and slows activity down
what are the physical changes in the sympathetic branch
increased heart rate- speed up blow flow to vital organs
increased breathing rate- increase oxygen intake
pupil dilation- improve vision
reduced functioning of the digestive system- save energy for prioritised functions such as running
muscle tension- improve reaction time and speed
what are the physical changes in the parasympathetic branch
rest and digest
decreases heart rate
decreases breathing rate
constricts pupils
stimulates digestion
relaxes muscles
dilates blood vessels
strength of fight or flight
practical application- has allowed us to come up with strategies to counteract its effects
learning relaxation techniques to counter fight or flight
In modern society we do not often feel stressed by situations that are life or death and the release of hormones can have a negative effect on health
thus practical applications can have positive implications for the economy and reduce the effects
weaknesses of fight or flight
more than two responses- freeze response
during the freeze response, humans are hypervigilant while they appriase the situation and decide the best course of action
gender bias- women have tend a befriend response, women more likely to protect their offspring and form alliances with other women
highlights a beta bius within psychology
what is the localisation of function
refers to the principle that different areas of the brain have different functions
what are the 4 lobes in the brain
- frontal lobe
- occipital lobe
- temporal lobe
- parietal lobe
the function of the frontal lobe
higher-order functioning such as planning, thinking, organising and abstract reasoning and logic
the function of the parietal lobe
integrates information from the different senses, an important role in spatial navigation
the function of the occipital lobe
processes visual information
the function of the temporal lobe
processes auditory information, language and memory
the function of the motor cortex
responsible for all voluntary movements, located in the frontal lobe
the function of the somatosensory cortex
processes sensory input from skin, muscles and joints related to touch located in the parietal lobe
function of the visual cortex
associated with vision, information form the eyes are transmitted to this area, located in the occipital lobe
function of the auditory cortex
concerned with hearing, processes sound along with volume, pitch and the location of the sound, located in the temporal lobe
what is Broca’s area
Paul Broca discovered a small area of the frontal lobe responsible for speech production
what is Broca’s aphasia
damage to this area of the brain meant that patients could understand spoken language but were unable to articulate meaningful sentences and speak or express their thoughts in writing
what is Wernicke’s area
Karl Wernick identified an area in the frontal lobe of the brain responsible for language comprehension
what is Wernicke’s aphasia
damage to Wernicke’s area meant that patients could not understand spoken language or from coherent meaningful sentences. they could utter words but they often lacked meaning
strengths of localisation of function
supporting research- brain scans
practical application- individuals who have suffered from a stroke
weaknesses of localisation of function
counter research- EB lost ost of his left hem
methodological issues- case studies, idiogrpahic
plasticity
what is lateralisation of function
refers to the idea that that different hemispheres of the brain have different specializations
what is the left hemisphere responsible for
language
what is the right hemisphere responsible for
creativity
what is the corpus callosum
it connects the 2 hemispheres so that information received by one hemisphere can be passed over to the other
what is split-brain research
Sperry did a quasi-experiment where he studied a group of individuals (11 participants) who had all undergone the same surgical procedure
they had their corpus callosum cut down the middle in order to separate the 2 hemispheres in order to treat epilepsy
information presented to one hemisphere had no way of travelling to the other hemisphere
information can only be processed in the hemisphere that receives it.
what was the task used in split-brain research
the patients would be asked to focus on a dot in the centre of the screen and at the same time information would be presented on either left or right visual field
they would be asked to make responses
left hand- controlled by the right hemisphere
right hand- controlled by the left hemisphere
explain the describe what you see finding
when a picture of an object was shown in the right visual field they could easily describe what they saw
when a picture of an object was shown on the left visual field they could not describe what they saw
this is because the right visual field gets projected to the left hemisphere which deals with language.
a word presented to the left visual field is presented to the right hemisphere which has no language centre
conclusion- the left hemisphere is dominant in language
explain the recognition by touch finding
if patients are shown an object in the left visual field they could easily pick up the object from a selection behind a screen with their left hand
however, they could not explain why they are selecting it
the right hemisphere can recognise basic nouns
they could also pick up an object closely associated to the one that they were shown in the left visual field
if 2 different objects were placed in each hand then put into a pile of items each hand searched for its own item
if the left hand picked up the item that was in the right hand they would put it down and reject it
strengths of split-brain research
supporting research- Rasmussen and Milner
- found the left hemisphere was more concerned with language
- found right hemisphere was more concerned with spatial and artistic functioning
- this was reinforced by a researcher who stated the right on the brain was the creative side whereas the left side was more logical.
this supports sperry as it shows the human brain is laterlaised with each hemisphere having different functions
another strength of split-brain research
methodology- high levels of control
-Sperry created a very carefully controlled procedure
- to stop the participant’s natural tendency to move their eye towards the stimulus
- the stimulus was only presented for around 200 milliseconds
- this ensured only the visual field aiming to be tested actually saw the stimulus, so only one hem was tested at a time
this is a strength as it allowed sperry to carry out a wide range of variations which has extended our understanding of brain lateralization
what is the weakness of Sperrys methodology
lacks ecologcial valdity
- the tasks the particooants were doing was high controlled
- e.g. sperry ensuring the participants did not have enough time to move their eyes towards the stimulus
- this does not reflect behaviour in everyday life
- it is likely they would use both eyes to compensate for the loss of the corpus callosum
therefore its difficult to make generalisation on laterlaisation based on split brain research
what is a weakness of split-brain research
population validity
11 particitpnsts
- differences in the operations carried out- some patients had smaller pathways which connect the 2 hemispheres cut as well, some other didn’t have this
counter-evidence- JW
- split-brain research suggests that the right aside of the brain cannot handle language
- case studies have demonstrated this is not necessarily the case
- researcher did a report on JW weho developed the ability to speak out of he’s right hemisphere
JW can now talk about information that is presented to either sides of the hemishpheres
this contradicts the suggestion that each side of the brain only has specific functions
it shows that the brain can adapt and plasticity casn occur where some parts of the brain take over parts that have been damaged
what is plasticity
refers to the ability of the brain to change and adapt synapses, pathways and structures in light of various experiences
when does plasticity occur
- at the beginning of life
- after brain injury to compensate for lost function
- during adulthood when we learn and memorise something
what is synaptic pruning
where pathways and connections die off due to lack of use
what is bridging
when new connections are created due to use and new stimulus
what is apoptosis
neurones die if they do not have a purpose to survive
what is functional recovery
a form of plasticity whereby other areas of the brain take over the function of the damaged ones
what is spontaneous recovery
happens quickly after trauma, whereby the brain starts adapting
how does functional recovery occur
through
- axon sprouting
- denervation supersensitivity
- recruitment of homologous areas
what is axon sprotuing
the axons of surviving neurons gown new branches that make synapses in areas of the brain formerly supplied by damaged neurones
what is denervation supersensitivity
when axons that do a similar job become aroused to a higher level, to compensate for the ones who are lost
what is the recruitment of homologous areas
where the opposite side of the brain performs similar tasks
example- if Broca’s area was damaged the right side equivalent would carry out its functions
after a period of time functionality would shift back to the left side
what is a strength of plasticity and functional recovery
practical application- brain injury therapy
- after brain injury therapy can be used to try to maintain and continue improvements from spontaneous recovery in functioning
-gradual re-training is though to be needed for the brain to be able to reorganise
- techniques may include movement-theraoy and electrical stimulation of the brain
as this therapy works it shows that the brain can change via plasticity and functional recovery after trauma
what is the supporting research for plasticity
maguire et al- taxi drivers
- 16 male taxi drivers compared to 50 non-taxi drivers
- MRI scans carried out to analyse the amount of grey matter in the brain
- the posterior hippocampus of the taxi drivers was significantly larger to the control group
-the volume of the hippocampus positively correlated with the amount of time spent as a tax driver
there requirement to learn the knowledge may have altered the structure of the taxi drivers brsisn
weaknesses of plasticity and functional recovery
not stiaght forward- not always a smooth transition
when function is recovered it requires considerable to do task
this can leave the individual feeling fatigued
other factors such as stress and alcohol can also effect the ability to use a function that has been ragained
plasticity can be affected by other factors and individual differences
another weakness of plasticity
gender differences
a researcher examined 325 patients with brian traume who had received rehabilitation and completed a follow up a year later
- when assessed on cognitive skills women perfomraed significantly better than men on tests of attention/ working memory and language
- males outperformed females on visual analytical skills
- women had a better recovery than men
this questions the extent to which plasticity and recovery of the brain after trauma can occur and how it occurs
also reinforces the need for any rehabilitation programmes to account for gender
