Neurons And Synaptic Transmission

Question 1

what is a neuron?

Answer 1

cells that are specialised to carry neural info throughout the body

Question 2

How many types of neuron are there and what are they called?

Answer 2

3
sensory
motor
relay

Question 3

Where is the dendrite located and what is it’s function?

Answer 3

At one end of the neuron and receives signals from other neurons or from sensory receptors.
connected to the cell body.

Question 4

What does the cell body do?

Answer 4

The control centre of the neuron

Question 5

What is the role of the axon?

Answer 5

Where the nerve impulse is carried along and terminates at the axon terminal.

Question 6

What is a sensory neurons?

Answer 6

carries nerve impulses from sensory receptors (receptors for vision, touch and taste) to the spinal cord and brain.

Question 7

Where are sensory receptors found in the body?

Answer 7

eyes
ears
tongue
skin

Question 8

What do sensory neurons do?

Answer 8

Convert info from sensory receptors into neural impulses.
When these impulses reach the brain they’re translated into sensations e.g. heat or pain so that the organisms can act accordingly.

Question 9

How do reflex actions occur?

Answer 9

Not all sensory neurons travel as far as the brain as some terminate at the spinal cord which allows reflex actions to occur quickly without the delay of sending impulses to the brain.

Question 10

Where are relay neurons located?

Answer 10

Within the brain and the spinal cords.

Question 11

What do relay neurons do?

Answer 11

Allow sensory and motor neurons to communicate.

Question 12

What is synaptic transmission?

Answer 12

The process by which nerve impulse passes across the synaptic cleft from one neuron (the presynaptic neuron) to another (the postsynaptic neuron).

Question 13

What is a synapse?

Answer 13

The conjunction of the end of the axon of one neuron, and a dendrite or cell body of another.

Question 14

What is the physical gap between the pre-and post synaptic cell membranes called?

Answer 14

This synaptic gap

Question 15

Where are the synaptic physicals located and what do they do?

Answer 15

At the end of the axon of the nerve cells.
Contain neurotransmitters that assist in the transfer of the impulse.

Question 16

Describe the process of synaptic transmission.

Answer 16

Action potential arrives at the terminal button at the end of the axon and needs to be transferred to another neuron or to tissue.
Neurotransmitters cross the synaptic gap in order for action potential to reach the synaptic vesicles.
Neurotransmitters release their contents through exocytosis.
The released neurotransmitter disused across the pre- and post synaptic cell + binds to specialised receptors on the surface of the cell that recognise it + are activated by that particular neurotransmitter.
Once activated the receptor molecules produce either excitatory or inhibitory effects on the postsynaptic neuron.
SEE DIAGRAM ON PAGE 151:)

Question 17

How long does it take for synaptic transmission to take place?

Answer 17

A fraction of a second

Question 18

Describe the process of “re-uptake“

Answer 18

Neurotransmitter is taking up again by the presynaptic neuron and stored and made available for later release.

Question 19

What is a neurotransmitter?

Answer 19

The chemical messengers that carries signals across the synaptic, gap to the receptor site on the postsynaptic cell.

Question 20

What can neurotransmitters be classified as?

Answer 20

Excitatory
Inhibitory

Question 21

What is an example of excitatory neurotransmitter and what is it referred to as?

Answer 21

Noradrenaline or Acetylcholine
The nervous systems ‘on switches’

Question 22

What does excitatory neurotransmitters do?

Answer 22

Increase the likelihood that an excitatory signal is sent to the postsynaptic cell, which is then more likely to fire.

Question 23

What is an example of an inhibitory neurotransmitter and what are they refer to as?

Answer 23

Serotonin or GABA
The nervous system’s ‘off switches’

Question 24

What are inhibitory neurotransmitter is responsible for?

Answer 24

Calming for mind and body, inducing, sleep, and filtering out unnecessary, excitatory signals.

Question 25

What doesn’t excitatory neurotransmitter finding of a postsynaptic receptor cause?

Answer 25

An electrical change in the membrane of that cell resulting in the excitatory postsynaptic potential (EPSP).
Meaning that the postsynaptic cell is more likely to fire.

Question 26

What doesn’t inhibitory neurotransmitter finding of a postsynaptic receptor cause?

Answer 26

Results in inhibitory postsynaptic potential (IPSP), making it less likely that the cell will fire.

Question 27

What is the likelihood of a cell firing determined by?

Answer 27

Adding up the excitatory and inhibitory synaptic input.

Question 28

How can the strength of an EPSP increased?

Answer 28

Spatial summation - a large number of EPSPs generated that many different synapses on the same postsynaptic neuron at the same time.
Temporal summation - a large number of EPSPs generated at the same synapse by a series of high frequency action potentials on the presynaptic neuron.