Brain structure

Question 1

description of the CNS

Answer 1

• consists of the brain and the spinal cord
• nerves in body send info via the spinal cord to the brain
• brain processes that info and senses a message to the body through the spinal cord
  -cells in CNS are called neurons - pass messages through electrical impulses.

Question 2

give examples of neurotransmitters

Answer 2

dopamine - related to emotion and cognitive functions
serotonin - associated with mood control, particularly in the limbic system.

Question 3

describe how message is passed on in the CNS (2)

Answer 3

An electrical impulse triggers the release of neurotransmitters from the vesicles. These travel across synaptic gap, to the receptor sites of the past synaptic neurone which act like lock and key mechanism, to pass the message on.

Question 4

describe the re-uptake of a neurotransmitter

Answer 4

a neurotransmitter that is not used up by the receptors is reabsorbed back into pre-synaptic neurone OR broken down by enzymes.

Question 5

strengths of neurotransmitters

Answer 5

• PET scanning by Jovanovic to study serotonin levels of women with and without PMDD (showed difference in synaptic receptors = evidence that neurotransmitters relate to mood.
• human brain scanning has scientific credibility

Question 6

weaknesses of neurotransmitters

Answer 6

allen and stevens 1994 found that synaptic transmission regarding hippocampal neurons was very unreliable, less than half neurotransmitters arriving from pre synaptic to post synaptic = may mean there are many factors at work in synaptic transmission

• hard to generalise animal studies with human brains (different structure)

Question 7

effect of cannabis on transmission process in the CNS

Answer 7

• bind to cannabinoid receptors
• many of these receptors found in hippocampus and therefore taking cannabis can affect memory function
• cannabis binds to cannabinoid receptors, blocking them = less activity in neurons
• but in reward system more dopamine is released, as happens with other drugs - it is this excess dopamine which gives the high

Question 8

strengths of the effects on drugs on the transmission process in the CNS

Answer 8

• observations of those who take drugs gives credibility
  -Olds and Milner who found pleasure centre in the brain linking recreational drugs creating excess dopamine = high

Question 9

weaknesses of effects on drugs on the transmission process of the CNS

Answer 9

• more than one reward pathway and brain region so too simplistic to have one explanation
• animal studies can’t be applied to human brains.