UNIT 3 - KA4

Question 1

What does the nervous system consist of

Answer 1

The nervous system consist of a complex network of nerve cells called neurons.

Question 2

What is the function of neurons

Answer 2

Neurons receive and transmit electrical impulses (nerve impulses) and provide the body with a rapid means of communication and control

Question 3

What are the three types of neuron

Answer 3

1. Sensory
2. Inter
3. Motor

Question 4

What does sim do

Answer 4

Sim does crazy actions

A nerve impulse always travels:

Dentrites ———> cell body ———> axon

Question 5

Draw and label sensory neuron from left to right

Answer 5

Dentrites - axon - cell body - myelin sheath - axon terminals

direction of nerve impulse ———>

Question 6

What is a difference in the structure of sensory neuron to other neurons

Answer 6

The cell body sits part way along the axon and there are no Dentrites on the cell body

Question 7

Draw and label inter neuron from left to right

Answer 7

Dendrites - cell body - axon - axon terminals

Question 8

What is the difference in the structure of inter neurons to other neurons

Answer 8

The axon is very short and lacks myelination

Question 9

Draw and label motor neuron from left to right

Answer 9

Dendrites - cell body - axon- myelin sheath - motor end

——— > direction of nerve impulse

Question 10

Dendrite

Answer 10

Receive nerve impulse and pass them towards a cell body

Question 11

Cell body

Answer 11

The control centre of the cells metabolism and contains clusters of ribosomes. And contains the nucleus and most of the cytoplasm

Question 12

Axon

Answer 12

An axon is a single nerve fibre that carries nerve impulses away from a cell body

Question 13

Myelin

Answer 13

Axons are surrounded by a myelin sheath which insulates the axon and increases the speed of impulse conduction

Question 14

When is myelination completed

Answer 14

Myelination is not completed at birth, but continues from birth until adolescence

Question 15

What happens to the response to stimuli in the first two years as a result of myelination

Answer 15

Responses to stimuli in the first two years of life are not as rapid or co-ordinated as those of an older child or adult

Question 16

What can certain diseases do to myelin sheath

Answer 16

Certain diseases destroy the myelin sheath causing a loss of coordination

Question 17

What is the function of glial cells

Answer 17

Glial cells produce the myelin sheath and support neurons

Question 18

Where do neurons connect

Answer 18

Neurons connect with other neurons or muscle fibres at a synaptic cleft

Question 19

What are the neurons before and after the synapse called

Answer 19

The neurone before the synapse is called the presynaptic neuron and the neuron after the synapse is called the post synaptic neuron

Question 20

Where are neuron transmitters stored (1st stage of transmission at a synapse)

Answer 20

1. Neurotransmitters are stored in the vesicles in the axon endings of the presynaptic neuron

Question 21

Where are the neurotransmitters released (2nd stage of transmission at a synapse)

Answer 21

They (the neurotransmitters) are released into the (synaptic) cleft on arrival of an impulse

Question 22

Where do they diffuse (3rd stage of transmission at a synapse)

Answer 22

3. They (the neurotransmitters) diffuse across the cleft

Question 23

What do neurotransmitters bind to (4th stage of transmission at a synapse)

Answer 23

4. They (neurotransmitters)bind to receptors on the membrane of the postsynaptic neuron

Question 24

Draw and label diagram of the synapse

Answer 24

Check jotter

Question 25

Transmission at a synapse summary

Answer 25

Neurotransmitters are stored in vesicles in the axon endings of the presynaptic neuron. They are released into the cleft on arrival of an impulse. They diffuse across the cleft and bind to receptors on the membrane of the postsynaptic neuron

Question 26

Where do neurotransmitters relay impulses

Answer 26

Neurotransmitters relay impulses across the synaptic cleft

Question 27

What should happen to neurotransmitters as soon as the impulse is transmitted

Answer 27

Neurotransmitters must be rapidly removed by enzymes or reuptake as soon as the impulse is transmitted to prevent continuous stimulation of postsynaptic neurons

Question 28

What can nerve impulses be

Answer 28

Nerve impulses can be excitatory or inhibitory

Question 29

Excitatory

Answer 29

Excitatory signals increase the chance of impulse being transmitted

Question 30

Inhibitory

Answer 30

Inhibitory signals decrease the chance of the impulse being transmitted

Question 31

What determines whether the signal is excitatory or inhibitory

Answer 31

Receptors determine whether the signal is excitatory or inhibitory not the neurotransmitter

Question 32

How is the threshold reached on the post synaptic membrane to transmit an

Answer 32

A minimum number of neurotransmitter molecules must attach to the receptors in order to reach the threshold on the postsynaptic membrane to transmit the impulse

Question 33

What can synapses filter out

Answer 33

Synapses can filter out weak stimuli arising from insufficient secretion of neurotransmitter.

Question 34

What series is enough to trigger an impulse

Answer 34

Summation of a series of weak stimuli can release enough neurotransmitter to trigger an impulse

Question 35

Which type of neural pathway can release enough neurotransmitter to reach the threshold

Answer 35

Convergent Neural pathways can release enough neurotransmitter molecules to reach the threshold and trigger an impulse

Question 36

What is the function of endorphins

Answer 36

Endorphins are neurotransmitters that stimulate neurons involved in reducing the intensity of pain

Question 37

What does the production of endorphins increase in response to

Answer 37

Endorphin production increases in response to severe injury, prolonged and continuous exercise, stress and certain foods

Question 38

Which feelings are increased levels of endorphins linked to

Answer 38

Increased levels of endorphins are also linked to the feelings of pleasure obtained from activities such as sex, eating and prolonged exercise

Question 39

What is the function of dopamine

Answer 39

Dopamine Is a neurotransmitter that induces feelings of pleasure and reinforces particular behaviour by activating the reward pathway in the brain

Question 40

Which neurons does the reward pathway involve

Answer 40

The reward pathway involves neurons which secrete or respond to dopamine

Question 41

When is the reward pathway activated

Answer 41

The reward pathway is activated when an individual engages in a behaviour that is beneficial to them eg. Eating when hungry

Question 42

What are many drugs used to treat neurotransmitter related disorders

Answer 42

Many drugs used to treat neurotransmitter related disorders are agonists or antagonists

Question 43

What are agonists

Answer 43

Agonists are chemicals that bind to and stimulate specific receptors mimicking the action of a neurotransmitter at a synapse

Question 44

What are antagonists

Answer 44

Antagonists are chemicals that bind to specific receptors blocking the action of a neurotransmitter at a synapse

Question 45

How do other drugs act

Answer 45

Other drugs act by inhibiting the enzymes that degrade neurotransmitters or by inhibiting uptake of the neurotransmitter at the synapse causing an enhanced effect

Question 46

What can recreational drugs act as

Answer 46

Recreational drugs can also act as agonists or antagonists

Question 47

How do recreational drugs affect neurotransmission

Answer 47

Recreational drugs affect neurotransmission at synapses in the brain altering an individuals mood, cognition, perception and behaviour

Question 48

Which pathway can recreational drugs affect

Answer 48

Many recreational drugs affect neurotransmission in the reward pathway of the brain

Question 49

What is drug addiction caused by

Answer 49

Drug addiction is caused by repeated use of drugs that act as antagonists

Question 50

What is drug tolerance caused by

Answer 50

Drug tolerance is caused by repeated use of drugs that act as agonists

Question 51

How do antagonists affect the nervous system

Answer 51

Antagonists block specific receptors causing the nervous system to increase both the number and sensitivity of these receptors

Question 52

Which sensation leads to addiction

Answer 52

Antagonists block specific receptors causing the nervous system to increase both the number and sensitivity of these receptors. This sensation leads to addiction where the individual craves more of the drug

Question 53

How do agonists affect the nervous system

Answer 53

Agonists stimulate specific receptors causing the nervous system to decrease both the number and sensitivity to these receptors

Question 54

Which desensitation leads to drug tolerance

Answer 54

Agonists stimulate specific receptors causing the nervous system to decrease both the number and sensitivity of these receptors. This desensitisation leads to drug tolerance where the individual must take more of the drug to get an effect