Neurons + Synaptic Transmission

Question 1

What are neurons?

Answer 1

Neurons are the building blocks of the nervous system, they are never cells

Question 2

Where are neurons located?

Answer 2

Neurons are located within the brain

Question 3

How many types of neurons are there? What are the different types called?

Answer 3

There are three types of neurons: sensory neuron, motor neuron relay neuron

Question 4

What is the function of the relay neuron?

Answer 4

The relay neuron connects sensory neurons to motor neurons or other neurons. Essentially a connector neuron

Question 4

What is the function of the sensory neuron?

Answer 4

The sensory neuron carry messages from the peripheral nervous system to the central nervous system

Question 5

How would the sensory neuron, motor neuron and relay neuron work together?

Answer 5

For example the body receives a stimulus (touching something hot) this stimulus will be picked up by a sensory neuron and passed onto a relay neuron which will pass the information directly onto a motor neuron. This information is passed onto an effector (muscle gland) to receive a response

Question 6

What is the function of the motor neuron?

Answer 6

The motor neuron carries nerve impulses from the central nerv ous system to an effector (muscle/gland)

Question 7

Where is the neuron located: RELAY? SENSORY? MOTOR?

Answer 7

RELAY: located within the brain and the visual system
SENSORY: located in the peripheral nervous system
MOTOR: located in the central nervous system

Question 7

What is the structure of the: RELAY? SENSORY? MOTOR?

Answer 7

RELAY: has short dendrites and short axons
SENSORY: long dendrites and short axons
MOTOR: has short dendrites and long axons

Question 8

In clusters xx

What form is the sensory neuron found in when located in the peripheral nervous system?

Answer 8

In clusters called ganglias

Question 9

What is the function of dendrites?

Answer 9

Dendrites carry impulses from neighbouring neurons towards the cell body

Question 10

What is the function of axons?

Answer 10

Axons carry impulses away from the cell body down the length of the neuron towards the axon terminals

Question 11

What is the axon covered in? How is this cover described? What is the function of the cover

Answer 11

The axon is covered in a fatty layer called the myelin sheath which protects the axon and speeds up the electrical transmission of the impulse

Question 12

The myelin sheath has gaps within it, what are these gaps called?

Answer 12

The gaps are called the nodes of Ranvier

Question 13

What is the function of the node of Ranvier

Answer 13

The nodes of Ranvier speed up the transmission of the electrical transmission by forcing the impulse to jump across the gaps down the axon

Question 14

What is a synapse?

Answer 14

A synapse is the very small gap between neurons that act as a bridge for communications between two neurons

Question 15

When neurons are at rest, what does this refer to?

Answer 15

When neurons are at rest, it means they are not sending any signals to one another. When at rest neurons are negatively charged inwardly relative to their outside

Question 16

Action potential is also known as the neuron doing what? During action potential, what is created?

Answer 16

Action potential is also known as a neuron firing. During action potential an electrical impulse is created

Question 16

When a neuron is activated by a stimulus, what occurs?

Answer 16

When a neuron is activated by a stimulus it becomes positively charged for a small amount of time, this causes what is known as action potential

Question 17

Where does this electrical impulse travel to?

Answer 17

The electrical impulse created travels through the axon to the end of the neuron (terminal buttons)

Question 18

How does a signal get from one neuron to another neuron?

Answer 18

Neurons do not make direct contact, they cross the synapse to continue their to/from the CNS. This is done through the use of chemicals which diffuse across the gap between two neurons

Question 19

How are signals transmitted within neurons? How are signals transmitted between neurons?

Answer 19

Signals are transmitted within neurons electrically. Signals are transmitted between neuron chemcially

Question 20

What is the process of neuron communication

Answer 20

1. The nerve impulse reaches axon terminal (the presynaptic terminal)
2. This triggers the release of neurotransmitters
3. neurotransmitters cross synaptic gap taken up by postsynaptic gap on dendrites of next neuron
4. Chemical message is then converted back into electrical impulse and the whole process begins again

Question 21

How do neurotransmitters travel?

Answer 21

In one direction

Question 22

Why do neurotransmitter travel in one direction?

Answer 22

Neurotransmitters are released from. the presynaptic neuron terminal and received by the postsynaptic neuron

Question 23

Neurotransmitters have two effects on neighbouring neurons, what are these called?

Answer 23

Excitatory effect and inhibitory effect

Question 24

What is the inhibitory effect neurotransmitters have on other neurons? What is an example of a neurotransmitter having an inhibitory effect?

Answer 24

Neurotransmitter act by making the neuron more negatively charged so they are less likely to fire. For example low levels of serotonin have been linked to depression

Question 25

What is the excitatory effect neurotransmitters have on other neurons?

Answer 25

Other neurotransmitters increase the positive charge to make the neuron more likely to fire. For example caffeine encourages dopamine to be released into synapses. This makes the erpson feel more alert and able to focus

Question 26

What is the process of stimulation?

Answer 26

The process of stimulation is the process whereby the sum of excitatory and inhibitory signals at any one time has to reach the threshold in order to trigger the action potential of the postsynaptic neuron

Question 27

What is the difference between a neuron and a neurotransmitter?

Answer 27

Neurons are nerve cells whereas neurotransmitters ae chemicals that communicate signals from one neuron to another across the synapse

Question 28

Give one difference between the autonomic nervous system and the somatic nervous system? (responsibilities)

Answer 28

The autonomic nervous system is responsible for functions like stress response and the somatic nervous system is in control of muscle movement