KA4- Cells Of The Nervous System And Neurotransmitters At Synapses

Question 1

Structure of neurons

Answer 1

Dendrites
Cell body
Axons

Question 2

Dendrite

Answer 2

Receives neurotransmitters from other neurons and signals from sense organs

Question 3

Cell body

Answer 3

Contains nucleus, cytoplasm, ribosomes etc
Control centre of cells metabolism

Question 4

Axon

Answer 4

Carries nerve impulses from the cell body to the next neuron

Question 5

Direction of nerve impulse

Answer 5

Dendrite —> cell body —> axon

Question 6

Myelin sheath

Answer 6

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

Question 7

Gaps in the myelin sheath

Answer 7

Nodes

Question 8

Myelination

Answer 8

continues from birth to adolescence so 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 9

Destruction of myelin sheath

Answer 9

Certain diseases destroy the myelin sheath causing a loss of of coordination (incorrect transmission)

Question 10

Glial cells

Answer 10

Produce the myelin sheath and physically support neurons

Question 11

Chemical transmission at the synapse by neurotransmitters

Answer 11

Vesicles
Synaptic cleft
Receptors

Question 12

Presynaptic neuron

Answer 12

Neuron carrying signal before the synapse
Release neurotransmitter to cross gap and activate signal to post synaptic
Neurotransmitter is complementary to specific receptors on post synaptic neuron

Question 13

Synapse is

Answer 13

the tiny region into which the axon end of one neuron releases its neurotransmitters

Question 14

Vesicles containing neurotransmitters

Answer 14

occur only on one side of synapse to ensure nerve impulse is transmitted in one direction

Question 15

Synapses can

Answer 15

filter out weak stimuli arising from insufficient secretion of neurotransmitters

Question 16

Convergent neural pathways

Answer 16

can release enough neurotransmitter molecules to reach threshold and trigger an impulse

Question 17

The function of endorphins

Answer 17

neurotransmitters that stimulate neurons involved in reducing the intensity of pain

Question 18

Endorphin production increase in response to

Answer 18

Severe injury
Prolonged and continuous exercise
Stress
Certain foods

Question 19

Increased levels of endorphins are linked to

Answer 19

the feelings of pleasure obtained from activities such as eating, sex and prolonged exercises

Question 20

The function of dopamine

Answer 20

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

Question 21

The reward pathway involves

Answer 21

neurons which secrete or respond to dopamine

Question 22

The reward pathway is activated when

Answer 22

an individual engages in a behaviour that is beneficial to them, for example eating when hungry

Question 23

Drugs which are used to treat neurotransmitter-related disorders

Answer 23

Agonists
Antagonists
Inhibitors of neurotransmitter enzymes
Reuptake inhibitor

Question 24

Agonists

Answer 24

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

Question 25

Antagonists

Answer 25

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

Question 26

Inhibitors of neurotransmitter enzymes

Answer 26

Inhibit the enzymes that degrade the neurotransmitters (in a synaptic cleft)

Question 27

Reuptake inhibitor

Answer 27

Inhibit reuptake of neurotransmitter at the synapse causing an enhanced effect

Question 28

Recreational drugs

Answer 28

can also act as agonists or antagonists affected neurotransmission (many in the reward pathway) at synapses in the brain altering an individuals mood, cognition, perception and behaviour

Question 29

Drug addiction

Answer 29

Caused by repeated use of drugs that act as antagonists Antagonists block specific receptors causing the nervous system to increase both the number and sensitivity to these receptors

Question 30

Sensitisation (antagonists)

Answer 30

leads to addiction where the individual craves more of the drug.

Question 31

Drug tolerance

Answer 31

Caused by the repeated use of drugs that act as agonists Agonists stimulate specific receptors causing the nervous system to decrease both the number and sensitivity of these receptors

Question 32

Desensitisation (agonists)

Answer 32

Leads to drug tolerance where the individual must take more of the drug to get an effect