U3KA4

Question 1

What is a neuron?

Answer 1

its a nerve cells that carries electrical signals throught the body.

Question 2

What are the three main structures of a neuron?

Answer 2

dendrites, cell body and axon.

Question 3

What does the dendrite do?

Answer 3

it receives signals from sense organs and other neurons.

Question 4

What is the axon?

Answer 4

its a long fibre that transmits the electrical signal

Question 5

What does the cell body contain?

Answer 5

the nucleus and other cell organelles.

Question 6

What is the axon fibre surrounded by?

Answer 6

myelin sheath.

Question 7

How does the myelin sheath help the axon of a neuron?

Answer 7

this insulates that axon and allows for faster transmission of signals down the axon.

Question 8

When is the myelin sheath formed?

Answer 8

from birth to teenage years, this is why young toddlers have such poor reaction speeds and coordination.

Question 9

What is the myelin sheath produced by?

Answer 9

glial cells, they also help support the neuron and keep it in place/

Question 10

What is a synapse?

Answer 10

its a tiny gap between the end of one neuron and the dendrites of another.

Question 11

How does the electrical signal pass through the synapse?

Answer 11

electrical signal travels down the axon fibre of the presynaptic neuron –> presynaptic knob –> neurotransmitter move to the surface of the prenysynaptic knob releasing it into the synaptic cleft –> cross on the membrane of the postnynaptic neuron and bind to complementary receptors

Question 12

What is a presynaptic neuron?

Answer 12

the neuron before the synapse

Question 13

Postsynaptic membrane receptors can be _____ or _____

Answer 13

excitatory or inhibitory

Question 14

What does it mean when a postsynaptic receptor is excitatory?

Answer 14

they increase the chance of generating a signal in the neuron

Question 15

what does it mean when a postsynaptic receptor is inhibitory?

Answer 15

they decrease the chance of generating a signal in the neuron.

Question 16

What are the two ways to remove neurotransmitters?

Answer 16

reuptake and enzyme breakdown

Question 17

why must neurotransmitters be removed?

Answer 17

the postsynaptic would be continually stimulated transmitting the same signal permanently.

Question 18

How are neurotransmitters removed through reuptake?

Answer 18

they move back into the presynaptic neuron via channel proteins,

Question 19

How are neurotransmitters removed through enzyme breakdown?

Answer 19

enzymes in the synpatic cleft break down the neutransmitters.

Question 20

What does the threshold do?

Answer 20

they transmit impulses by a minimum number of neurons that only transmit signals when the stimulus is big enough.

Question 21

In a converging neural pathway, a series of ________ release s small amount of neurotransmitters. The combined effect of these neurotransmitters is enough to reach _____ and trigger an ______.

Answer 21

weak stimuli, threshold, impulse.

Question 22

Neurotransmitter can affect our cognisitive processing, ______, and _____. They control pathways that can affect feelings of ______, _____, _____, _____ and _______

Answer 22

mood, behaviour, sleep, hunger, aggression, coordination and memory.

Question 23

What are endorphins?

Answer 23

neurotransmitters that stimulate neurons involved in reducing the intesity of pain. they decrease stress and improve symptoms of depression/

Question 24

What is dopamine?

Answer 24

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

Question 25

What is the reward pathway?

Answer 25

its a pathway that responds to dopamine.

Question 26

When does the reward pathway activate?

Answer 26

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

Question 27

What are the 4 main categories of drugs that are used to target neurotransmitters relate disorders?

Answer 27

agonists, antagonists, drugs that inhibit uptake and drugs that inhibit neurotransmitter breakdown enzymes.

Question 28

What are agonists?

Answer 28

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

Question 29

What are antagonists?

Answer 29

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

Question 30

What do drugs that inhibit reuptake do?

Answer 30

keep neurotransmitters in the synaptic cleft by preventing them from entering the channels in the presynaptic neuron

Question 31

What do drugs that inhibit breakdown enzymes do?

Answer 31

keep neurotransmitters in the synaptic cleft by inhibiting the enzymes that break them down.

Question 32

What are recreational drugs?

Answer 32

they are substances that are taken for a temporary physiological effect, not for a medical reason. They tamper with levels of neurotransmitters causing changes in mood, behaviour, perception and cognition.

Question 33

What does repeated use of recreational drugs cause?

Answer 33

addiction or tolerance.

Question 34

Why are recreational drugs addictive?

Answer 34

because it tends to stimulate the reward pathway in the brain.

Question 35

repeated use of _____ drugs cause very little stimulaton of a neural pathway.

Answer 35

antagonist

Question 36

repeated use of an _____ drug causes over-stimulation of a neural pathway.

Answer 36

agonist

Question 37

How does antagonist drugs cause addiction?

Answer 37

they block receptors of neurotransmitters that can cause negative sensations such as pain, in response the postsynaptic builds more receptors on its membrane, resulting in sensitisation. Which leads to addiction.

Question 38

How do agonist drugs cause tolerance?

Answer 38

they stimulate receptors of neurotransmitters that can cause positive feelings such as relaxation, in response the postsynaptic neuron reduces the number of receptors at the synapse resulting in desensitization which leads to tolerance.