CGP Flashcards
(37 cards)
Rod cells in the dark
. Sodium ions pumped out of cell using active transport, but diffuse back in through open sodium channels
. Cell membrane is depolarised
. This triggers release of neurotransmitters, which inhibit bipolar neurone
Rod cells in the light
. Light breaks apart rhodopsin into retinal and opsin
. Bleaching of rhodopsin causes sodium ion channels to close - can diffuse out, but can’t diffuse back in
. Sodium ions build up on outside of cell - cell is hyperpolarised
. Stops releasing neurotransmitters
. Bipolar neurone depolarises.
Define:
Synaptic divergence
Synaptic convergence
Summation
. When one neurone connects to many neurones to disperse information around the body
. When many neurones connect to one neurone to amplify information
. Effect of neurotransmitter released from many neurones is added together
Function of cerebrum
. Vision, learning, thinking, emotions + environment
Function of hypothalamus
Body temperature regulation
Produces hormones to control pituitary gland
Medulla oblongata function
. Breathing + heart rate
Cerebellum function
Coordinating movement + balance
Cerebellum function
Coordinating movement + balance
CT
Shows damaged + diseased parts of the brain (blood)
Blood has a lighter colour - shows extent + location of bleeding
MRI
Shows difference between normal and abnormal tissue
E.g. shows tumour size + location
fMRI
Detects blood flow
More active areas in brain require more blood flow
Detects areas where less signal is absorbed
fMRI
Detects blood flow
More active areas in brain require more blood flow
Detects areas where less signal is absorbed
PET
radioactive tracer is introduced shows which areas of brain are unusually active/inactive
Describe how low serotonin levels in an individual can affect the transmission of impulses in their brain
. Serotonin is a neurotransmitter
. (less serotonin) results in fewer depolarisations of post
synaptic membranes (1)
. threshold not achieved / less chance of action potential
being produced (in post-synaptic neurone) (1)
Explain how MDMA works
. Increases serotonin levels
. Increases serotonin levels by inhibiting reuptake of serotonin into presynaptic neurones - binds to and blocks reuptake protein on post synaptic membrane
. Also triggers release of serotonin from presynaptic neurones
. Serotonin levels stay high in synapse and cause depolarisation of postsynaptic neurones in part of brain that control mood
. Effect of MDMA is mood elevation
Explain how L-Dopa works
. Structure is very similar to Dopamine
. Absorbed by brain and converted into dopamine by dopa-decarboxylase - increasing dopamine level in brain
. Higher dopamine = more nerve impulses transmitted across synapses in parts of brain that control movement
. Sufferers of Parkinson’s disease have more control over movement.
How does Parkinsons disease work
. Neurones in part of brain that control movement are destroyed
. These normally produce dopamine
. Less dopamine released into synaptic clefts, less bind to receptors on post synaptic membrane
. Fewer sodium ion channels open on post synaptic membrane, so postsynaptic cell is less likely to depolarise
. Fewer action potentials produced, causes tremors + slow movement
.
How does depression work
. Low levels of serotonin neurotransmitter
. Serotonin transmits nerve impulses across synapses in parts of the brain that control mood
Animal experiments
. Study effects of different environments on brain development of same species - genetically similar, so any differences in brain development will be from nurture instead of nature.
. Study effects of different genes, genetically engineer mice ot lack particular gene and raise mice with and without gene in similar environments - difference in brain development would be nature not nurture
.
Cross cultural studies
. Different cultures = different environmental influences can study effects of different upbringing on brain development on children with same age but different cultures
Any differences in brain development would be nurture not nature, any similarities would be nature not nurture.
Brain damage studies
Scientists compare development of a chosen function in children with and without brain damage
if characteristic still develops in children with brain damage, brain development for that characteristic is more likely to be nurture
if it doesn’t develop, brain development for that characteristic is more likely nature.
Why should we use animals in medical research
. Animals are similar to humans - have led to many medical breakthroughs
. Only done when necessary
. Scientists follow strict rules
. Pain is minimised
. Currently only way to study how a drug affects the whole body
. Humans have greater right to life than animals
Why shouldnt we test on animals
. Different to humans, drugs have different effects
. Experiments cause pain and distress
. Alternatives to using animals in research
. Animals have the right not to be experimented on
Individuals who use MDMA may develop the symptoms of depression.
MDMA use results in depletion of serotonin (1)
post synaptic membrane becomes less responsive to
serotonin / loss of receptors on post synaptic membrane (1)
serotonin levels affect mood / lack of serotonin associated
with depression (1)
