The cells of the nervous system and neurotransmitters at synapses

Question 1

What are neurons?

Answer 1

nerve cells

Question 2

What do neurons contain?

Answer 2

cell body and fibres called dendrites and axons

Question 3

What are the three types of neuron?

Answer 3

sensory,inter and motor

Question 4

What is myelination?

Answer 4

Covering of the neuron fibres with a myelin sheath (surrounded by axons), which stimulates them, increasing the speed of nervous impulses

Question 5

When does myelination start and continue to?

Answer 5

From birth to adolescence

Question 6

What do glial cells do?

Answer 6

physically support neurons and produce the myelin sheath

Question 7

What are synapses?

Answer 7

Gaps between neurons

Question 8

What are neural pathways?

Answer 8

Routes taken by impulses through the nervous system

Question 9

Describe the responses to stimuli in the first two years of life

Answer 9

Not as rapid or co-ordinated as those of an older child or adult

Question 10

What can certain diseases do to the myelin sheath?

Answer 10

Destroys it causing a loss of coordination

Question 11

Describe neurotransmitters at synapses

Answer 11

chemical transmission at the synapse by neurotransmitters-vesicles,synaptic cleft and receptors

Question 12

What do neurons connect to and where

Answer 12

With other neurons or muscle fibres at a synaptic cleft

Question 13

Where do neurotransmitters relay impulses?

Answer 13

Across the synaptic cleft

Question 14

What are the neurotransmitters?

Answer 14

Acetylcholine
Noradrenaline
Serotonin
Dopamine

Question 15

What is acetylcholine broken down?

Answer 15

Broken down to non active products by an enzyme in postsynaptic membrane
Non active products are then reabsorbed by the presynaptic membrane
Resynthesized into acetylcholine which requires energy (anabolic)

Question 16

What do neurons provide the body with?

Answer 16

With rapid and communication

Question 17

What does neurons do?

Answer 17

Conduct nerve impulses from on one part of the body to another

Question 18

What do sensory neurons do?

Answer 18

From sense organs to CNS

Question 19

What do motor neurons do?

Answer 19

From CNS to effectors

Question 20

What are association neurons/ relay?

Answer 20

From sensory neurons to motor neurons

Are in CNS

Question 21

What is the myelin sheath?

Answer 21

Fatty material that insulates the axon

Question 22

Name two diseases associated with neurons

Answer 22

Multiple sclerosis

Motor neurons disease

Question 23

Transmission of impulse

Answer 23

1) An electrical impulse reaches the synapse
2) Causes vesicles in the presynaptic axon to release neurotransmitters
3) Neurotransmitters diffuse across the cleft to receptors on the dendrite of the postsynaptic neuron
4) If receptor is excitatory
5) And enough neurotransmitters are released
6) An electrical impulse is triggered which is stimulated along the neuron

Question 24

What does Noradrenaline do?

Answer 24

Reabsorbed y the presynaptic membrane and reused

Question 25

What do synaptic vesicles contain and where are they found?

Answer 25

They contain chemical neurotransmitters and are found in presynaptic neurons

Question 26

What do nervous transmission between neurons rely

Answer 26

Neurotransmitters secreted into the synaptic cleft

Question 27

What do receptors in the postsynaptic membrane respond to?

Answer 27

Neurotransmitters

Question 28

Why do neurotransmitters have to be removed from the synaptic cleft rapidly?

Answer 28

maintain sensitivity

Question 29

What happens after neurotransmitters are broken down by enzymes?

Answer 29

They are reabsorbed into the presynaptic membrane

Question 30

What do receptors determine?

Answer 30

Whether a signal is excitatory or inhibitory

Question 31

What can synapses filter out?

Answer 31

Weak stimuli resulting from insufficient secretion of neurotransmitters

Question 32

What can a summation of a series of weak stimuli trigger?

Answer 32

Enough neurotransmitter to fire an impulse

Question 33

What are neural pathways?

Answer 33

Routes taken by impulse through the nervous system

Question 34

What are converging neural pathways?

Answer 34

Impulses from several neurons passed to a single neuron increasing sensitivity to excitatory or inhibitory signals Visions to read in dim light

Question 35

What are diverging neural pathways?

Answer 35

Impulses from one neuron passed to several others so affecting more than one destination at one time Handwriting many muscles

Question 36

What are reverberating neural pathways?

Answer 36

Impulses which are recycled round look like pathways | Allowing repeated stimulation of the pathway, breathing

Question 37

Why are new neural pathways created?

Answer 37

To bypass areas of brain damage, to suppress reflexes or in response to sensory impulses

Question 38

What is given from the creation of new neural pathways?

Answer 38

Plasticity of response

Question 39

What are endorphins?

Answer 39

Neurotransmitters involved in reducing intensity of pain,release of sex hormone

Question 40

When does the endorphin production increase?

Answer 40

In response to severe injury, prolonged and continuous exercise, stress and certain foods

Question 41

What does dopamine do?

Answer 41

Induces the feelings of pleasure and reinforces particular behaviour in the reward pathway

Question 42

What do agonist drugs act like?

Answer 42

Neurotransmitters and can enhance transmission

Question 43

What does antagonistic drugs do?

Answer 43

bind to specific receptors, blocking the action of a neurotransmitter

Question 44

What can enzymes that degrade neurotransmitters or inhibit reabsorption do?

Answer 44

Can be inhibited by certain drugs

Question 45

What can recreational drugs do?

Answer 45

Mimic neurotransmitters, resulting in mood change, alteration of perception and changes in cognition and behaviour

Question 46

What do many recreational drugs affect?

Answer 46

Neurotransmission in the reward pathway

Question 47

What is sensation?

Answer 47

An increase in the number and sensitivity of receptors as a result of exposure to antagonistic drugs-this can lead to drug addiction

Question 48

What is desensitisation?

Answer 48

A decrease in the number and sensitivity of receptors as a result of exposure to agonists drugs- this can lead to drug tolerance