Unit 3 - Triggering Nerve Impulses

Question 1

Describe how nerve impulses are triggered

Answer 1

• A nervous impulse can only pass a synapse if a certain minimum number of neurotransmitter molecules are released into the synapse
• Weak stimuli fail to cause the release of sufficient molecules and so the impulse fails to pass. Synapses can ‘filter out’ weak stimuli arising from insufficient

Question 2

Describe the role of receptors in the transmission of nerve impulses

Answer 2

They determine whether the signal is excitatory or inhibitory

Question 3

Describe Dopamine

Answer 3

Dopamine → neurotransmitter that causes feelings of pleasure and reinforces particular behaviour by activating the reward pathway in the brain

Question 4

Describe the reward pathway in the brain

Answer 4

REWARD PATHWAY → Involves neurons which secrete or respond to dopamine
* It is activated when an individual engages in behaviour that is beneficial to them