6.2: The process of synaptic transmission

Question 1

Synaptic transmission

Answer 1

Synaptic transmission is the process by which neighbouring neurons communicate with each other by sending chemical messages across the gap (the synaptic cleft) that separates them

Question 2

Electron transmission - the firing of a neuron:

When a neuron is in a resting state, what?

Answer 2

When a neuron is in a resting state, the inside of the cell is negatively charged compared to the outside of the cell

Question 3

Electron transmission - the firing of a neuron:
When a neuron is in a resting state, the inside of the cell is negatively charged compared to the outside of the cell.
What happens when a neuron is activated by a stimulus?

Answer 3

When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second

Question 4

Electron transmission - the firing of a neuron:
When a neuron is in a resting state, the inside of the cell is negatively charged compared to the outside of the cell.
When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second, causing what?

Answer 4

When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second, causing an action potential to occur

Question 5

Electron transmission - the firing of a neuron:
When a neuron is in a resting state, the inside of the cell is negatively charged compared to the outside of the cell.
When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second, causing an action potential to occur.
What does this do?

Answer 5

This creates an electrical impulse that travels down the axon towards the end of the neuron

Question 6

How do neurons communicate with each other?

Answer 6

Neurons communicate with each other within groups

Question 7

Neurons communicate with each other within groups known as what?

Answer 7

Neurons communicate with each other within groups known as neural networks

Question 8

Neurons communicate with each other within groups known as neural networks.
Each neuron is what from the next neuron by a tiny gap called the synapse?

Answer 8

Each neuron is separated from the next neuron by a tiny gap called the synapse

Question 9

Neurons communicate with each other within groups known as neural networks.
Each neuron is separated from the next neuron by a tiny gap called the synapse.
Which signals are transmitted electrically?

Answer 9

Signals within neurons are transmitted electrically

Question 10

Neurons communicate with each other within groups known as neural networks.
Each neuron is separated from the next neuron by a tiny gap called the synapse.
Signals within neurons are transmitted electrically.
However, what?

Answer 10

However, signals between neurons are transmitted chemically

Question 11

Neurons communicate with each other within groups known as neural networks.
Each neuron is separated from the next neuron by a tiny gap called the synapse.
Signals within neurons are transmitted electrically.
However, signals between neurons are transmitted chemically where?

Answer 11

However, signals between neurons are transmitted chemically across the synapse

Question 12

Neurons communicate with each other within groups known as neural networks.
Each neuron is separated from the next neuron by a tiny gap called the synapse.
Signals within neurons are transmitted electrically.
However, signals between neurons are transmitted chemically across the synapse.
When the electrical impulse reaches the end of the neuron (the what)?

Answer 12

When the electrical impulse reaches the end of the neuron (the presynaptic terminal)

Question 13

Neurons communicate with each other within groups known as neural networks.
Each neuron is separated from the next neuron by a tiny gap called the synapse.
Signals within neurons are transmitted electrically.
However, signals between neurons are transmitted chemically across the synapse.
When the electrical impulse reaches the end of the neuron (the presynaptic terminal), what happens?

Answer 13

When the electrical impulse reaches the end of the neuron (the presynaptic terminal), it triggers the release of neurotransmitter

Question 14

Neurons communicate with each other within groups known as neural networks.
Each neuron is separated from the next neuron by a tiny gap called the synapse.
Signals within neurons are transmitted electrically.
However, signals between neurons are transmitted chemically across the synapse.
When the electrical impulse reaches the end of the neuron (the presynaptic terminal), it triggers the release of neurotransmitter from what?

Answer 14

When the electrical impulse reaches the end of the neuron (the presynaptic terminal), it triggers the release of neurotransmitter from tiny sacs

Question 15

Neurons communicate with each other within groups known as neural networks.
Each neuron is separated from the next neuron by a tiny gap called the synapse.
Signals within neurons are transmitted electrically.
However, signals between neurons are transmitted chemically across the synapse.
When the electrical impulse reaches the end of the neuron (the presynaptic terminal), it triggers the release of neurotransmitter from tiny sacs called what?

Answer 15

When the electrical impulse reaches the end of the neuron (the presynaptic terminal), it triggers the release of neurotransmitter from tiny sacs called synaptic vesicles

Question 16

Neurotransmitters

Answer 16

Neurotransmitters are brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another

Question 17

Neurotransmitters are brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another.
What can neurotransmitters be broadly divided into?

Answer 17

Neurotransmitters can be broadly divided into:

1. Those that perform an excitatory function
2. Those that perform an inhibitory function

Question 18

Neurotransmitters are brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another.
Neurotransmitters can be broadly divided into those that perform an excitatory function and those that perform an inhibitory function.
What happens once the neurotransmitter crosses the gap?

Answer 18

Once the neurotransmitter crosses the gap, it is taken up by the postsynaptic receptor site

Question 19

Neurotransmitters are brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another.
Neurotransmitters can be broadly divided into those that perform an excitatory function and those that perform an inhibitory function.
Once the neurotransmitter crosses the gap, it is taken up by the postsynaptic receptor site, the what?

Answer 19

Once the neurotransmitter crosses the gap, it is taken up by the postsynaptic receptor site, the dendrites of the next neuron

Question 20

Neurotransmitters are brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another.
Neurotransmitters can be broadly divided into those that perform an excitatory function and those that perform an inhibitory function.
Once the neurotransmitter crosses the gap, it is taken up by the postsynaptic receptor site, the dendrites of the next neuron.
Here, what happens?

Answer 20

Here, the chemical message is converted back into an electrical impulse and the process of transmission begins again in this other neuron

Question 21

How many types of neurotransmitter have been identified in the brain?

Answer 21

Several dozen types of neurotransmitter have been identified in the brain

Question 22

Several dozen types of neurotransmitter have been identified in the brain (as well as where)?

Answer 22

Several dozen types of neurotransmitter have been identified in the brain (as well as in the spinal cord and some glands)

Question 23

Several dozen types of neurotransmitter have been identified in the brain (as well as in the spinal cord and some glands).
What does each neurotransmitter have?

Answer 23

Each neurotransmitter has its own specific molecular structure

Question 24

Several dozen types of neurotransmitter have been identified in the brain (as well as in the spinal cord and some glands).
Each neurotransmitter has its own specific molecular structure that what?

Answer 24

Each neurotransmitter has its own specific molecular structure that fits perfectly into a post-synaptic receptor site

Question 25

Several dozen types of neurotransmitter have been identified in the brain (as well as in the spinal cord and some glands).
Each neurotransmitter has its own specific molecular structure that fits perfectly into a post-synaptic receptor site.
Neurotransmitters also have specialist what?

Answer 25

Neurotransmitters also have specialist functions

Question 26

Several dozen types of neurotransmitter have been identified in the brain (as well as in the spinal cord and some glands).
Each neurotransmitter has its own specific molecular structure that fits perfectly into a post-synaptic receptor site.
Neurotransmitters also have specialist functions.
Example

Answer 26

For example, acetylcholine (ACh) is found at each point where a motor neuron meets a muscle and, upon its release, it will cause muscles to contract

Question 27

Neurotransmitters have either a what or what effect on the neighbouring neuron?

Answer 27

Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron

Question 28

Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron.
Example

Answer 28

For example, the neurotransmitter serotonin causes inhibition in the receiving neuron

Question 29

Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron.
For example, the neurotransmitter serotonin causes inhibition in the receiving neuron, resulting in what?

Answer 29

For example, the neurotransmitter serotonin causes inhibition in the receiving neuron, resulting in the neuron becoming more negatively charged and less likely to fire

Question 30

Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron.
For example, the neurotransmitter serotonin causes inhibition in the receiving neuron, resulting in the neuron becoming more negatively charged and less likely to fire.
In contrast, what?

Answer 30

In contrast, adrenaline (an element of the stress response that is both a hormone and a neurotransmitter)

Question 31

Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron.
For example, the neurotransmitter serotonin causes inhibition in the receiving neuron, resulting in the neuron becoming more negatively charged and less likely to fire.
In contrast, adrenaline (an element of the stress response that is both a hormone and a neurotransmitter) does what?

Answer 31

In contrast, adrenaline (an element of the stress response that is both a hormone and a neurotransmitter) causes excitation of the post-synaptic neuron

Question 32

Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron.
For example, the neurotransmitter serotonin causes inhibition in the receiving neuron, resulting in the neuron becoming more negatively charged and less likely to fire.
In contrast, adrenaline (an element of the stress response that is both a hormone and a neurotransmitter) causes excitation of the post-synaptic neuron by doing what?

Answer 32

In contrast, adrenaline (an element of the stress response that is both a hormone and a neurotransmitter) causes excitation of the post-synaptic neuron by increasing its positive charge and making it more likely to fire

Question 33

What do excitatory potentials do?

Answer 33

Excitatory potentials make it more likely for the neuron to fire

Question 34

What do inhibitory potentials do?

Answer 34

Inhibitory potentials make it less likely for the neuron to fire

Question 35

Excitatory potentials make it more likely for the neuron to fire.
Therefore, if a synapse is more likely to cause the post-synaptic neuron to fire, then what?

Answer 35

Therefore, if a synapse is more likely to cause the post-synaptic neuron to fire, then it is called an excitatory synapse

Question 36

Inhibitory potentials make it less likely for the neuron to fire.
If the message is likely to be stopped at the post-synaptic neuron, then what?

Answer 36

If the message is likely to be stopped at the post-synaptic neuron, then it is called an inhibitory synapse

Question 37

Excitation

Answer 37

Excitation is when a neurotransmitter increases the positive charge of the postsynaptic neuron

Question 38

Excitation is when a neurotransmitter increases the positive charge of the postsynaptic neuron.
What does this do?

Answer 38

This makes it more likely that the neuron will fire and pass on the electrical impulse

Question 39

Inhibition

Answer 39

Inhibition is when a neurotransmitter increases the negative charge of the postsynaptic neuron

Question 40

Inhibition is when a neurotransmitter increases the negative charge of the postsynaptic neuron.
What does this do?

Answer 40

This makes it less likely that the neuron will fire and pass on the electrical impulse

Question 41

What does the process of summation do?

Answer 41

The process of summation decides whether a postsynaptic neuron does fire

Question 42

The process of summation decides whether a postsynaptic neuron does fire.
What are summed?

Answer 42

The excitatory and inhibitory influences are summed

Question 43

The process of summation decides whether a postsynaptic neuron does fire.
The excitatory and inhibitory influences are summed - What?

Answer 43

The excitatory and inhibitory influences are summed - If the net effect on the postsynaptic neuron is inhibitory, then the postsynaptic neuron is less likely to fire and if the net effect is excitatory, it is more likely to fire

Question 44

The process of summation decides whether a postsynaptic neuron does fire.
The excitatory and inhibitory influences are summed - If the net effect on the postsynaptic neuron is inhibitory, then the postsynaptic neuron is less likely to fire and if the net effect is excitatory, it is more likely to fire and momentarily, what happens?

Answer 44

The excitatory and inhibitory influences are summed - If the net effect on the postsynaptic neuron is inhibitory, then the postsynaptic neuron is less likely to fire and if the net effect is excitatory, it is more likely to fire and momentarily, the inside of the postsynaptic neuron becomes positively charged

Question 45

The process of summation decides whether a postsynaptic neuron does fire.
The excitatory and inhibitory influences are summed - If the net effect on the postsynaptic neuron is inhibitory, then the postsynaptic neuron is less likely to fire and if the net effect is excitatory, it is more likely to fire and momentarily, the inside of the postsynaptic neuron becomes positively charged.
Once the electrical impulse is created, what does it do?

Answer 45

Once the electrical impulse is created, it travels down the neuron

Question 46

The process of summation decides whether a postsynaptic neuron does fire.
The excitatory and inhibitory influences are summed - If the net effect on the postsynaptic neuron is inhibitory, then the postsynaptic neuron is less likely to fire and if the net effect is excitatory, it is more likely to fire and momentarily, the inside of the postsynaptic neuron becomes positively charged.
Once the electrical impulse is created, it travels down the neuron.
Therefore, what?

Answer 46

Therefore, the action potential of the postsynaptic neuron is only triggered if the sum of the excitatory and inhibitory signals at any one time reaches the threshold

Question 47

Yamamoto and Kitazawa (2001) examined why we cannot easily perceive when we are touched in two places simultaneously.
For example, if someone touches you on your shoulder and your toe at exactly the same time, it feels as if each is being touched at a slightly different time.
Conversely, if they are touched with a slightly delayed difference in time, you sometimes can’t tell which was touched first.
This is argued to be because of the inability of the nervous system to transmit that information accurately, as the distance from the brain for the neurons receiving the message is different

Answer 47

k

Question 48

The what mechanism at the receptor sites?

Answer 48

The lock and key mechanism at the receptor sites