exam past paper questions

Question 1

A survey of hospital patients has found that a new drug, Zapurpain, is as effective as other pain medication.
Explain one limitation of asking hospital patients to self-report the effectiveness of
Zapurpain.

Answer 1

• social desirability, patients may feel obliged to say the drug is effective at reducing their pain
• pain is subjective, a participant who has a higher pain threshold may report Zapurpain to be more
  effective for example.

Question 2

Zapurpain acts like an inhibitory neurotransmitter at the synapse.
Explain how Zapurpain might affect the process of synaptic transmission through inhibition.

Answer 2

• Zapurpain mimics the effect of inhibitory neurotransmitters, stimulation of postsynaptic receptors by an
  inhibitory neurotransmitter result in inhibition (hyperpolarisation) of the postsynaptic membrane
• when an inhibitory neurotransmitter binds to the post-synaptic receptors it makes the post-synaptic cell
  less likely to fire (IPSP)
• Summation – if inhibitory inputs are higher than excitatory they can cancel out excitation and inhibit an
  action potential occurring/Zapurpain would decrease the overall activity
• Zapurpain would make the post-synaptic cell less likely to fire
• reducing brain activity may lead to reduced pain.

Question 3

Explain one difference and one similarity between Functional Magnetic Resonance Imaging (fMRI) and Event-Related Potentials (ERPs) as ways of studying the brain.

Answer 3

difference - fMRIs have poor temporal resolution whereas ERPs have good temporal resolution
fMRIs have good spatial resolution whereas ERPs have poor spatial resolution
similarity- fMRIs and ERPs are both non-invasive and do not use radiation (risk free)
fMRIs and ERPs both measure brain activity linked to events/tasks.

Question 4

Describe the structure and function of a neuron.

Answer 4

• Neurons enable communication within the nervous system
• the cell body (soma) contains the genetic material
• branch-like dendrites extend from the cell body (often with dendritic spines)
• dendrites carry functional information towards the cell body
• dendrites can receive information from other neurons
• axons carry messages away from the cell body
• axons can be myelinated to increase speed of nerve transmission (saltatory conduction between
  nodes of Ranvier)
• terminal boutons are at the end of axons, these make synaptic connections with other cells * axon terminals contain neurotransmitters.

Question 5

Studies have identified Broca’s area and Wernicke’s area as responsible for language.
Outline the difference in function between Broca’s area and Wernicke’s area.

Answer 5

• Broca’s area is responsible for speech production whereas Wernicke’s area is responsible for language comprehension
• Broca’s area enables speech to be fluent whereas Wernicke’s area enables speech to be meaningful.

Question 6

Describe the divisions of the nervous system.

Answer 6

• the nervous system is divided into the central and peripheral nervous systems
• the CNS comprises the brain and spinal cord
• the peripheral nervous system is further divided into the somatic nervous system and the autonomic
  nervous system (ANS)
• the somatic nervous system consists of sensory and motor neurons to carry sensory and motor
  information to and from the CNS and also enables reflex actions
• the ANS acts largely unconsciously/involuntary
• the ANS is divided into the sympathetic nervous system (SNS) and the parasympathetic nervous
  system (PNS)
• the SNS prepares us for flight or fight
• the PNS balances the sympathetic nervous system providing ‘rest and digest’ functions.

Question 7

Xavier was cycling to school when he fell off his bike into the road. A teacher saw a car swerve, narrowly missing Xavier. The teacher checked Xavier was safe and asked him what had happened.
Xavier could hardly speak; his heart was pounding, and his mouth was dry. He felt sick and his hands were shaking. It took Xavier 20 minutes to feel calm again.

Outline the fight or flight response and use this to explain what Xavier was experiencing.

Answer 7

• the fight/flight response is generated by the sympathetic branch of the ANS
• the hypothalamus stimulates the SNS
• SNS stimulates the adrenal medulla to release adrenaline into the blood stream/endocrine system and
  noradrenaline is released
• generalised effects of adrenaline such as increased breathing rate, sweating, pupil dilation, etc
• adrenaline inhibits saliva production, which may explain Xavier’s dry mouth
• Xavier’s shaky hands may be caused by adrenaline as adrenaline increases muscle tension, causes
  an increase in heart rate (Xavier’s heart was pounding)/increases blood flow to muscles (which can cause limbs to shake) and adrenaline stimulates glucose to be released/increases blood sugar levels, providing more muscle fuel
• digestion is inhibited during SNS arousal, which may explain why Xavier felt sick
• once the stressor is gone the PNS acts to dampen the stress response and return the heart/breathing
  rate to resting levels/initiate digestion, etc, this may explain why after 20 mins Xavier calmed down.

Question 8

The electroencephalogram (EEG) and event-related potentials (ERPs) both involve recording the electrical activity of the brain.
Outline one difference between the EEG and ERPs.

Answer 8

EEG is a recording of general brain activity usually linked to states such as sleep and arousal, whilst ERPs are elicited by specific stimuli presented to the participant.

Question 9

Outline the structures and processes involved in synaptic transmission.

Answer 9

• A signal begins as an electrical impulse (an action potential) within the presynaptic neuron
• When the electrical impulse arrives at the end of the axon on the pre-synaptic knob, chemical messengers called neurotransmitters are released from structures called vesicles at the presynaptic membrane
• Neurotransmitters are released into the synaptic cleft as a chemical substance from the presynaptic neuron after the action potential has occurred
• Neurotransmitters diffuse across the synaptic cleft and temporarily bind with receptor sites on the postsynaptic membrane
• This action stimulates the postsynaptic neuron to generate another electrical impulse (action potential) that then travels down the axon of the postsynaptic neuron
• The neurotransmitter molecules are then destroyed by enzymes or recycled to prevent continued stimulation of the second neuron, which could cause repeated impulses to be sent
• The re-absorbed neurotransmitter may be used again by the presynaptic neuron

Question 10

Split brain patients show unusual behaviour when tested in experiments. Briefly explain how unusual behaviour in split brain patients could be tested in an experiment.

Answer 10

plausible experimental situation/set-up – eg split visual field, dichotic listening plausible stimulus – visual, faces, words, auditory, digits, music
plausible task for patient – verbal or visuospatial response, eg drawing, matching etc.

Question 11

Briefly evaluate research using split brain patients to investigate hemispheric lateralisation of function.

Answer 11

• the disconnection between the hemispheres was greater in some patients than others
• some patients had experienced drug therapy for much longer than others
• the comparison groups were not considered to be valid as they were often people with no
  history of epileptic seizures
• the data were artificially produced as in real life a severed corpus callosum can be
  compensated for by the unrestricted use of two eyes
• the research has added to the unity of consciousness debate
• research relates to small sample sizes.