Chapter 3 Chemical Messengers

Question 1

Synapses

Answer 1

Specialized regions in which action potentials are transmitted along axons to, where the axons contact the dendrites of other neurons.

Question 2

Neurotransmitters

Answer 2

are stored in tiny spherical bags called synaptic vesicles in the endings of axons.

Question 3

Synaptic cleft

Answer 3

the 20-nanometre gap

Question 4

Synaptic transmission step 1

Answer 4

Action potential arrives at the axon terminal, action potential depolarizes the membrane

Question 5

Synaptic transmission step 2

Answer 5

Voltage-gated Ca2+ channels open

Question 6

Synaptic transmission step 3

Answer 6

Ca2+ enters the cell

Question 7

Synaptic transmission step 4

Answer 7

Ca2+ signals to vesicles

Question 8

Synaptic transmission step 5

Answer 8

Vesicles move to the membrane

Question 9

Synaptic transmission step 6

Answer 9

Docked vesicles release neurotransmitters by exocytosis

Question 10

Synaptic transmission step 7

Answer 10

The neurotransmitter diffuses across the dynamic cleft and binds to receptors

Question 11

receptors

Answer 11

specialized molecular structures

Question 12

ionotropic receptors

Answer 12

an ion channel, if it allows positive ions to enter, the inflow of positive current leads to excitation.

Question 13

Glutamate

Answer 13

the main excitatory neurotransmitter in the brain

Question 14

inhibitory synapses

Answer 14

activation of receptors leads to the opening of ion channels that allow the inflow of negatively charged ions giving rise to a change in membrane potential called inhibitory postsynaptic potential

Question 15

GABA and glycine

Answer 15

inhibitory neurotransmitters

Question 16

messengers acting on G-protein coupled receptors

Answer 16

acetylcholine, dopamine, and noradrenaline.

Question 17

How many noradrenaline neurons are there in the human

brain?

Answer 17

1600

Question 18

metabotropic receptors

Answer 18

Many of these affect neuronal mechanisms by interacting with a very different set of proteins in the membranes of neurons called metabolic receptors are called.

Question 19

neuromodulation

Answer 19

the action of metabotropic receptors

Question 20

G-proteins

Answer 20

bridging molecules when a neurotransmitter is recognized and bound by a metabotropic receptor