Other Information

Question 1

Describe CNS

Answer 1

• Made up of the brain and the spinal cord
• Nerves in our body send information via the spinal cord to the brain
• The brain then processes this information and sends a message to the body through the spinal cord
• Cells in the CNS are known as neurons and they communicate with other around 1000 cells in huge networks
• The nervous system consists of neurones and glia
• Glia are cells that carry out repairs, act as insulators and remove waste from the brain. Neurones pass messages along through neurotransmitters

Question 2

Describe Neurotransmission

Answer 2

An action potential passes down the axon of the neuron to stimulate the release of neurotransmitters. This impulse pushes membranous sacks called vesicles which hold the neurotransmitters to the end of the cell were they are released into synaptic gap. The transmitters travel across the gap to the post synaptic neuron where they bind to receptors so the impulse can continue. Any neurotransmitters left will be absorbed by enzymes or taken back up by the presynaptic cell and repacked into vesicles so the process can start again.

Question 3

Explain effect of one neurotransmitter on behaviour: dopamine

Answer 3

Dopamine: Related to emotion and cognitive functions as well as posture and control of movement. It has also been associated with reinforcement in learning as well as dependency in drug addictions.

Dopamine is found in high levels in the limbic system (reward pathway) and has a pleasurable affect when released into the synaptic gap.

Question 4

Explain effect of one drug on behaviour: Opiods

Answer 4

Opiods: e.g. heronin: Reduces GABA activity. GABA is an inhibitory neurotransmitter which when it binds to receptors prevents the release of dopamine.

This therefore leads to overactivity of dopaminergic neurotransmission in the reward pathways of the brain creating intense feelings of pleasure and sometimes hallucinations

Question 5

Explain addiction to one drug

Answer 5

Withdrawal occurs when a drug is no longer active in our nervous system. This can result in withdrawal symptoms that are often unpleasant and dangerous.
During withdrawl the brain adapts to the changes imposed by the drug so that it no longer operates normally without the drug.
The brain adapts to the high level of dopamine caused by heroine and down regulates its own natural production of it; this means that the baseline of dopamine is now lower than before, so in order to get the same “high” the user now needs more dopamine and so more of the drug