Neurotransmission

Question 1

Why is it important to understand chemical communication?

Answer 1

All drugs used to treat behavioral disorders act on chemical communication systems

Question 2

What is the importance of the synapse? (what happens there?)

Answer 2

Where chemicals cross from one neuron to another (from the presynaptic side to the postsynaptic side)

Question 3

What determines whether or not an action potential will travel down the axon?

Answer 3

Depolarization where the cell body meets the axon (where the action potentials are)

Question 4

What are graded potentials?

Answer 4

Graded potentials are changes in membrane potential that vary in size, as opposed to being all-or-none

Question 5

Where are graded potentials found?

Answer 5

dendrites and cell body

Question 6

Following receptor activation, electrical changes can produce either…:

Answer 6

Inhibition: The neuron is more negative (hyperpolarization)

Stimulation: The neuron is more positive (depolarization)

Question 7

How does a graded potential turn into an action potential?

Answer 7

If a graded depolarization is strong enough (exceeds a threshold level), then an action potential is triggered

Question 8

What do chemical signals (neurotransmitters) do in the brain?

Answer 8

Induce graded potentials that excite
(depolarize) post-synaptic neurons.

– OR –

Inhibit (hyperpolarize) the post-synaptic
neuron.

Question 9

What are the 5 key neurotransmitters and are they excitatory or inhibitory?

Answer 9

GABA (inhibitory)
serotonin, dopamine, acetylcholine (both)
glutamate (excitatory)

Question 10

What are the 5 steps in synaptic transmission?

Answer 10

1. Synthesis
2. Storage
3. Release
4. Receptor Activation
5. Inactivation

Question 11

What happens during the synthesis step in synaptic transmission?

Answer 11

The neurotransmitter is manufactured in the cell (in the cell body)

Question 12

What happens during the storage step in synaptic transmission?

Answer 12

The neurotransmitter is stored in vesicles for protection

Question 13

What happens during the release step in synaptic transmission?

Answer 13

An action potential arriving at the axon terminal (end of the axon) will cause the vesicles to move to the membrane and release neurotransmitter into the synapse.

Question 14

What happens during the receptor activation step in synaptic transmission?

Answer 14

The neurotransmitters in the synapse can freely move about. If they interact with a receptor (bind to it) they activate the receptor to stimulate electrical changes in the postsynaptic neuron.

Question 15

What happens during the neurotransmitter inactivation step in synaptic transmission?

Answer 15

altered into inactive substances
OR
recycled (reuptake) back into the presynaptic vesicles.

Question 16

What happens when there are multiple action potentials coming frequently?

Answer 16

more entry of Ca2+, which causes more vesicles to release their neurotransmitter (stronger response)

Question 17

What ion does the action potential trigger?

Answer 17

The entry of Ca2+ into the cell

Question 18

What happens when Ca2+ enters the cell?

Answer 18

synaptic vesicles release neurotransmitters

Question 19

What happens when the neurotransmitters are released?

Answer 19

Ion channels open and ion flow changes the postsynaptic cell potential