Neurotransmitters

Question 1

Neurotransmitters

Answer 1

Chemical messenger released by neurones. Needs to pass a threshold. It is unidirectional meaning that it cannot happen the other way round

Question 2

Excitatory Neurotransmitters

Answer 2

Neurotransmitters that increase the likelihood of a new action potential forming the postsynaptic cell. When detected by receptors in the postsynaptic cell, excitatory neurotransmitters make the electrical charge inside more positive and more likely to fire - Depolarisation. (Positively charged sodium ions Na+ enter the postsynaptic cell)

Question 3

Inhibitory Neurotransmitters

Answer 3

Neurotransmitters that decrease the likelihood of a new action potential forming the postsynaptic cell, inhibitory neurotransmitters make the electrical charge inside more negative and less likely to fire - Hyper-polarisation. (Positively charged potassium ions K+ leave the postsynaptic cell)

Question 4

Summation

Answer 4

The combined (summed) effect of all the excitatory and inhibitory neurotransmitter influences on the post synaptic neurone. If a threshold is reached, then a new action potential will form in the postsynaptic cell.

Question 5

Agonists

Answer 5

increase the neurotransmitter effect (making the excitation or inhibition stronger)

Question 6

Antagonists

Answer 6

reduce the effect of neurotransmitters (making the excitation or ignition weaker)

Question 7

Neurotransmitters are

Answer 7

endogenous agonists - that is, they bind to and activate receptor sites on the post synaptic neuron.

Question 8

Drugs are

Answer 8

exogenous agonists. They act in the same way, but they are not natural in our onerous system (eg: alcohol).