Biopsychology - 02 Neurons & Synaptic Transmission

Question 1

What are the 3 basic parts of a neuron?

Answer 1

Cell body
Dendrites
Axon

Question 2

What is the role of the myelin sheath?

Answer 2

It speed up transmissions by insulating the neurons

Question 3

What is an action potential?

Answer 3

It shoots an electrical charge down the axon to its terminals in the neighbouring neurons

Question 4

What are neurons?

Answer 4

Cells that are specifically designed to carry neural information throughout the body

Question 5

What are the 3 types of neuron and what order do they go in?

Answer 5

Sensory
Relay
Motor

Question 6

How does a neuron work? (4 steps)

Answer 6

1- Cell body has dendrites that carry nerve impulses from neighbouring neurons towards the cell body

2-Information passes along axon in the form of electrical impulses. The axon is covered in a fatty layer of myelin sheath that protects the axon and speeds up transmission

3-At the end of the axon are terminal buttons that communicate with the nest neuron in the chain across a gap known as the synapse

4-Neurotransmitters are chemicals that are released from the terminal buttons and pass across the synapse. They bind to receptor sites on the dendrites of the nest neuron in order to pass on the signal

Question 7

what charge does the inside of a neuron have in a resting state?

Answer 7

Negatively charged

Question 8

What happens in electrical transmission?

Answer 8

When a neuron is activated by a stimulus, the inside becomes positively charged for a split second causing an action potential to occur. This creates an electrical impulse that travels down the axon towards the end of the neuron.

Question 9

What direction do the impulses travel in a sensory neuron?

Answer 9

From PNS to CNS

Question 10

Where are the sensory neurons found?

Answer 10

Various locations around the body like eyes, ears, tongue and the skin

Question 11

What do the sensory neurons do?

Answer 11

Convert information from sensory receptors into neural impulses which are then translated into sensations when they reach the brain.

Question 12

Where are relay neurons found?

Answer 12

in the brain and spinal cord (CNS)

Question 13

What do relay neurons do?

Answer 13

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

Question 14

What direction do the impulses travel in a motor neuron?

Answer 14

From the CNS to the PNS

Question 15

Where are the motor neurons located?

Answer 15

In the CNS but project their axons outside the CNS

Question 16

What do motor neurons do?

Answer 16

Form synapses with muscles and control their contractions
Release neurotransmitters that bind to receptors on muscles and triggers a response that leads to motor movement

Question 17

What is synaptic transmission?

Answer 17

The process by which nerve impulses pass across the synaptic gap from one neuron to another

Question 18

What are the 6 steps of synaptic transmission?

Answer 18

1-Action potential arrives at axon terminal of presynaptic neuron
2-Vesicles in axon terminal contain neurotransmitters
3-Action potential causes vesicles to move forwards and fuse with presynaptic membrane and release neurotransmitters into synaptic gap
4-Neurotransmitters diffuse across synaptic cleft and binds to receptor sites on dendrite of next neuron
5-Receptors recognise the neurotransmitters and behave accordingly
6-neurotransmitters are recycled (reuptake) or broken down by enzymes at the end of the process

Question 19

Why is synaptic transmission unidirectional?

Answer 19

Impulses at synapses only travel in one direction, from the presynaptic neuron to the postsynaptic neuron
neurotransmitter are only found in the presynaptic neuron and receptors only postsynaptic neuron membrane

Question 20

What is inhibition?

Answer 20

When a neurotransmitter increases the negative charge of the postsynaptic neuron which decreases the likelihood that the neuron will fire and pass on the electrical impulse

Question 21

What is an example of inhibition?

Answer 21

Serotonin
Responsible for calming the mind and body, inducing sleep and filters out unnecessary excitatory signals

Question 22

What is excitation?

Answer 22

When a neurotransmitter increases the positive charge of the postsynaptic neuron.
This increases the likelihood that the neuron will fire and pass on the electrical impulse

Question 23

What is an example of excitation?

Answer 23

Dopamine
Switches on the nervous system

Question 24

What does summation control?

Answer 24

Whether a postsynaptic neuron fires or not

Question 25

What happens if the net effect on the postsynaptic neuron is inhibitory?

Answer 25

The postsynaptic neuron is less likely to fire

Question 26

What happens if the net effect on the postsynaptic neuron is excitatory?

Answer 26

The postsynaptic neuron is more likely to fire, the inside of the postsynaptic neuron momentarily becomes positively charged