Neurons and synaptic transmission

Question 1

What are neurons?

Answer 1

Specialised cells that are specalised to carry out neutral information throughout the body.

Question 2

What are the three types of neurons?

Answer 2

Sensory
Relay
Motor

Question 3

What do neurons typically consist of?

Answer 3

A cell body
Denrites
An Axon

Question 4

What do dendrites receive?

Answer 4

Signals from other neurons or sensory receptors

Question 5

What are dendrites connected to?

Answer 5

The cell body

Question 6

What is the cell body know as?

Answer 6

Control centre of the neuron

Question 7

From the cell body where does the impulse travel along and to?

Answer 7

Along the axon

terminates at the axon terminal

Question 8

What is the insulating layer that forms around the axon called?

Answer 8

Myelin sheath

Question 9

What does the Myelin sheath allow?

Answer 9

Allows nerve impulses to transmit more rapidly along the axon

Question 10

What happens if the Myelin sheath becomes damaged?

Answer 10

Impulses slow down

Question 11

What is the length of a neuron?

Answer 11

A few millimetres up to one metre

Question 12

What do sensory neurons carry?

Answer 12

Nerve impluses from sensory receptors to the spinal cord and the brain

Question 13

Where are sensory receptors found?

Answer 13

Various locations around the body 
For example:
Eyes
Ears 
Toungue 
Skin

Question 14

What do sensory neurons convert information from these sensory receptors?

Answer 14

Neural impulses

Question 15

What happens when these impulses reach the brain?

Answer 15

Translated into sensations of
for example
visual input
heat pain

Question 16

Why does not all sensory information travel as far as the brain?

Answer 16

They are terminated at the spinal cord

Allows reflect actons to occur quickly without delay of sending impulses to the brain

Question 17

What do relay neurons allows?

Answer 17

They allow sensory and motor neurons to communicate with each other.

Question 18

Where do you find relay neurons?

Answer 18

In the brain and spinal cord

Question 19

What do motor neurons form?

Answer 19

Synapses with muscles and control their contractions

Question 20

What happens when motor neurons are stimulated?

Answer 20

neurotransmitters are released

Question 21

What happens when the neurotransmitters are released?

Answer 21

They bind to receptors on the muscles which triggers a reponse which leads to muscles movement

Question 22

What causes muscles relaxation?

Answer 22

Caused by inhibition of the motor neuron

Question 23

What needs to happen to the action potential when it arrives at the terminal at the end of an axon?

Answer 23

It needs to be transferred to another neuron or to tissue

Question 24

For the action potential to be successful transferred what must occur?

Answer 24

It must cross a gap between the presynaptic neuron and the postsynaptic neuron

Question 25

What is the area of the end of the presynaptic neurom and the membrane of the postsynaptic neuron called?

Answer 25

Synapse

Question 26

What is the physical gap between the pre- and post synaptic call membranes known as?

Answer 26

Synaptic gap

Question 27

What is found at the end of axon of the nerve cell?

Answer 27

A number of sacs AKA Synaptic vesticles

Question 28

What do synaptic vesticles contain?

Answer 28

Chemical messengers

Question 29

What do the chemical messengers do?

Answer 29

Assist in the transfer of the impulse

Question 30

As the action potential reaches the synaptic vesticles what happens?

Answer 30

It causes them to release their contents through a process called EXOCYTOSIS

Question 31

What happens after the transmitter has diffused across the gap between pre- and post synaptic cell?

Answer 31

Binds to specialised receptors on the surface of the cell that recognised it and are activated by that particular neurotransmitter

Question 32

What happens once receptors have been activated?

Answer 32

Receptors molecules produce either excitatory or inhibitory effects on the postsynaptic neuron

Question 33

How long does the process of post synaptic transmission take?

Answer 33

A fraction of a second

Question 34

What is the process of re-uptake?

Answer 34

Neurotransmitter is taken up again by the presynaptic neuron, where it is stored and made available for later release

Question 35

What does the speed that the presynaptic neuron takes back the neurotransmitter from the synaptic cleft determine?

Answer 35

how prolonged the effects will be

Question 36

If it is taken back quickly what does this mean?

Answer 36

The shorter the effects on the presynaptic neuron

Question 37

Some examples of excitatory neurotransmitters?

Answer 37

Acetylcholine and noradrenaline

Question 38

What are excitatory neurotransmitters?

Answer 38

Neurotransmitters that increase the likelihood of a new action potential forming in the postsynaptic cell

Question 39

What happens when excitatory neurotransmitters are detected in the postsynaptic cell?

Answer 39

Electrical charge inside becomes more positive and more likely to fire - depolarisation

Question 40

What are inhibatory neurotransmitters?

Answer 40

Neurotransmitters that decrease the likelihood of a new action potential forming in the postsynaptic cell

Question 41

What happens when inhibitory neurotransmitters are detected by receptors in the postsynaptic cell?

Answer 41

Electrical charge inside becomes more negative and less likely to fire - Hyperpolarisation

Question 42

What is summation?

Answer 42

Effect of all th excitatory and inhibitory neurotransmitters influences on the postsynaptic neuron

Question 43

What happens in the threshold is met?

Answer 43

A new action potential will form in the postsynaptic cell