These notes contain everything you need to know about each of the biopsychology on the specification for AQA A level psychology! This includes a large amount of AO1 and following 4 evaluations in PEEL format for any possible 16 markers. In a very few cases there will be 3 but each of them are detai...
The nervous system and the endocrine system
- Nervous system divided into the central nervous system and the peripheral nervous system
- It communicates using electrical signals
- Two functions: respond to information in the environment (CNS) and to co-ordinate functions of
different organs the body (PNS)
- Central nervous system (CNS) consists of the brain and the spinal cord
- Brain is associated with conscious actions - outer layer of the cerebral cortex
- The brain is divided into two hemispheres - spinal cord is an extension of the brain
- It exchanges messages to and from the brain and connects nerves to the PNS
- Responsible for our unconscious actions (reflex actions)
- Peripheral nervous system (PNS) sends information to the CNS and transmits messages from CNS to
muscles and glands in the body
- PNS is divided into the autonomic nervous system (ANS) and the somatic nervous system (SNS)
- Autonomic nervous system (ANS) is ’autonomic' as the system operates involuntarily
- ANS governs vital functions such as breathing, heart rate, digestion and stress responses
- Two divisions: the sympathetic and parasympathetic nervous systems
- Somatic nervous system (SNS) governs muscle movement, receives information from sensory receptor
- Endocrine system is made of glands that release hormones directly into the bloodstream
- These hormones are carried towards target organs in the body - communicate via chemicals
- Different glands located throughout the body: pituitary gland, hypothalamus, thyroid, parathyroid,
adrenals, pancreas, ovaries, testes
- It is slower than the NS buts its effects are more powerful
- Endocrine and autonomic nervous system work together
- When a stressor is received the hypothalamus activates the pituitary gland and this triggers the
sympathetic branch of the autonomic nervous system
- This causes the ANS to change from its resting state (parasympathetic state) to the physically aroused
state (sympathetic state)
- The stress hormone, adrenaline, is then released from the adrenal medulla into the bloodstream
- Adrenaline - stimulating heart rate, contracting blood vessels, dilating air passages and fight or flight
- Fight or flight response is the way an animal responds when stressed. The body becomes physiologically
aroused in readiness to fight an aggressor or, in some cases, flee
- After the threat has passed the parasympathetic nervous system returns the body to its resting state
- The parasympathetic NS and sympathetic NS work opposite of each other
- How the parasympathetic
nervous system and the
sympathetic nervous
system oppose each other
, Neurons and synaptic transmission
- Neurons: nerve cells that process and transmit messages through electrical and chemical signals
- There are three types of neurons: Sensory, relay and motor neurons
- Sensory neurons carry messages from the PNS to the CNS - long dendrites and short axons
- Relay neurons connect sensory neurons to the motor neurons - short dendrites and short axons
- Motor neurons connect CNS to effectors such as muscles and glands - short dendrites and long axons
- The structure of the neuron:
- Contain a cell body with a nucleus - contains the genetic material of the cell
- Dendrites are branch endings from the cell body - allows neurons to connect
- The axon carries the impulses away from the cell body
- Myelin sheath - fatty layer around the axon - speeds up electrical transmission
- Gaps known as nodes of Ranvier - electrical impulses jumps through gap
- Gaps between the neurons are known as synapse
- Location of neurons:
- Sensory neurons are located outside of the CNS in the PNS
- Relay neurons are mostly found within the brain and spinal cord
- Motor neurons can be found in the CNS but their axon form parts of the PNS
- At resting potential the inside of the neuron is more negatively changed that the outside
- When activated the inside becomes more positively charged causing an action potential
- Synaptic transmission - neurons communicate with each other by sending chemical messages
across the gap (synapse) that separates them
- Signals within neurons are transmitted electrically and gaps between neurons signals chemically
- When the electrical impulse reaches the end of the neuron (the presynaptic neuron) triggers
the release of neurotransmitter
- Neurotransmitter is absorbed by the postsynaptic neuron - converted from chemical message
back into the electrical impulse
,- Neurotransmitters can either have an excitatory or inhibitory effect
- Excitation is when a neurotransmitter, such as adrenaline, increases the positive charge of the
postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will pass on the
electrical impulse
- Inhibition is when a neurotransmitter, such as serotonin, increases the negative charge of the
postsynaptic neuron. This decreases the likelihood that the postsynaptic neuron will pass on the
electrical impulse
Localisation of functions in the brain
- Localisation of function - theory that different areas of the brain are responsible for specific behaviours
- Therefore if certain areas of the brain are damaged then the associated functions will also be affected
- Before this theory scientist supported the holistic theory - all parts were involved in thoughts and actions
- The cerebrum is divided into two symmetrical halves called the left and right hemisphere
- Lateralisation is when some of our physical and psychological functions are controlled or dominated by
one hemisphere eg language is dominated by the left hemisphere for most people
- Activity on the left hand side of the body is controlled by the right hemisphere and the activity on the
right hand side of the body is controlled by the left hemisphere
- The cerebral cortex is the outer layer of both hemispheres - divided into four centres known as lobes
- A ‘lobe’ is a part of an organ that is separate in some way from the other lobes (different functions)
- At the back of the frontal lobe (both hemispheres) is the motor area
- Motor area is a region of the frontal lobe involved in regulating movement
- Damage to the area can result in a loss of control in movements
- Somatosensory area is an area of the parietal lobe that processes sensory information such as touch
- Damage to this area could mean that the person is unable to feel pain or determine temperature on skin
- It is separated from the motor area by a ‘valley’ called the central sulcus
- Visual area is a part of the occipital lobe that receives and processes visual information
- Information from the right visual field to the left visual cortex and information from the
left visual field will go to the right visual cortex
- Therefore damage to the left hemisphere can result in blindness in the right visual field
- Auditory area is located in the temporal lobe - analysis of speech-based information
- Damage to this area could result in partial hearing loss
, - However language is restricted to the left hemisphere of the brain for most people
- Broca's area is an area of the frontal lobe in the left hemisphere responsible for speech production
- Damage to Broca’s area can result in slow speech and lacking in fluency (Broca’s aphasia)
- Wernicke's area - temporal lobe in the left hemisphere responsible for language comprehension
- These people are fluent in language but struggle to understand what it means
- Wernicke’s aphasia is damage to this area in the left temporal lobe - leads to nonsense words
Evaluation:
- P: One strength is that damage to areas of the brain has been linked to mental disorders.
- E: Dougherty et al. (2002) reported on 44 people with OCD who had undergone a cingulotomy. About
30% had met the criteria for successful response to the surgery and 14% for partial response.
- E: Neurosurgery (surgery on the brain) is a last resort method for treating some mental disorders,
targeting specific areas of the brain which may be involved.
- L: The success of these procedures suggests that behaviours associated with serious mental disorders
may be localised.
- P: Another strength is evidence from brain scans that supports the idea that brain functions are localised.
- E: Brain scans have demonstrate Wernicke's area was active during a listening task and Broca's area was
active during a reading task.
- E: Buckner and Petersen (1996) also revealed that semantic and episodic memories reside in different
parts of the prefrontal cortex. These studies confirm localised areas for everyday behaviours.
- L: Therefore objective methods have provided scientific evidence that brain functions are localised.
- P: One limitation is research that challenges the localisation theory.
- E: Lashley (1950) removed areas of the cortex in rats that were learning the route through a maze. No
area was proven to be more important than any other area in terms of the rats' ability to learn route.
- E: The process of learning seemed to require every part of the cortex rather than being confined to a
particular area.
- L: This suggests advanced processes, such as learning, are not localised - distributed in a holistic way.
- P: One limitation is that language may not be localised just to Broca's and Wernicke's areas.
- E: Dick and Tremblay (2016) found that only 2% of modern researchers think that language in the brain is
completely controlled by Broca's and Wernicke's areas.
- E: Brain imaging techniques, such as fMRI, have shown that language function is distributed far more
holistically in the brain than was first thought.
- L: This suggests that language may be organised holistically in the brain, contradicting localisation theory.
Hemisphere lateralisation and split-brain research
- Hemispheric lateralisation is the idea that two halves (hemispheres) of the brain are functionally different
and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than
the other for example language (which is localised as well as lateralised)
- There are two main centres for language in the left hemisphere for most people
- Brocha’s area is in the left frontal lobe and Wernicke's area is in the left temporal lobe
- In the motor area the brain is cross-wired (contralateral wiring)
- The RH controls movements on the left side of the body whereas the LH controls right side of the body
- Vision is both contralateral and ipsilateral (opposite and same side)
- Each eye receives information from the left visual field and the right visual field
- Visual information is processed in the left hemisphere from the LVF. It also connects to the RH and visual
information from the RVF is processed in the RH but can also be processed in the LVF
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