3.1.1-3.1.2 the CNS and aggression

Question 1

What makes up the nervous system?

Answer 1

CNS and peripheral nervous system

Question 2

What makes up the CNS?

Answer 2

brain and spinal cord

Question 3

What is the role of the CNS?

Answer 3

-control body’s functions
-interpret sensory info and pass on to brain
-responsible for all voluntary and involuntary decisions

Question 4

What are neurotransmitters?

Answer 4

Chemical messengers that operate between neurones and the brain in order to process thoughts/memories in the brain (across synapse)

Question 5

What are neurones?

Answer 5

cells of the nervous system which carry electrochemical messages called nerve impulses

Question 6

What are the 3 types of neuron?

Answer 6

motor, inter, sensory

Question 7

function of a motor neuron

Answer 7

transmits messages from CNS to muscles

Question 8

function of inter neuron

Answer 8

connect neurons to others, located in the brain

Question 9

function of sensory neuron

Answer 9

carry info from senses to CNS

Question 10

What is the link between neurons and nerves?

Answer 10

Nerves are bundles of neurons

Question 11

Special elements of a neuron

Answer 11

-dendrites (finger like structures surrounding nucleus)
-axon (extends from nucleus and reaches to axon terminal)

Question 12

What is a synapse?

Answer 12

A gap between the dendrite and axon terminal

Question 13

What passes over a synapse?

Answer 13

Neurotransmitters/chemical messages

Question 14

Benefit of synapses

Answer 14

allow each axon to communicate with a number of dendrites, forming a complex communication system

Question 15

How does synaptic transmission work?

Answer 15

-process electrical signals and turn into chemical signals and back to electrical
-action potential causes neurotransmitter to be released into synapse
-neurotransmitter binds to receptor site of post synaptic neuron

Question 16

What happens if neurotransmitters aren’t accepted?

Answer 16

-must be removed for next stimulation
-neurotransmitters broken down by enzymes
-reuptake occurs

Question 17

What does action potential do?

Answer 17

the method by which the nerve impulse passes down the axon of the neuron to stimulate the release of neurotransmitters

Question 18

How does action potential cause change?

Answer 18

-tiny electrical impulse triggered by change in electrical potential of neuron

Question 19

How does the charge of a neuron change?

Answer 19

-inside of neuron has slight negative charge, outside is more positive at rest
-when stimulated, positive particles enter and the neuron is depolarised
-some positive particles are pushed back out and neuron returns to depolarised state

Question 20

Define depolarization

Answer 20

when the resting potential of a neuron changes from negative to more positive

Question 21

Define hyperpolarization

Answer 21

opposite to depolarization, change in a cells membrane potential that makes it more negative

Question 22

What are the 3 hormones that are linked to drug taking?

Answer 22

serotonin, dopamine, glutamate

Question 23

Effect of serotonin

Answer 23

-happiness and good mood
-low levels cause depression
-linked to an array of behaviours and mental disorders

Question 24

Effect of dopamine

Answer 24

-pleasure feeling
-addiction
-linked to reward pathway which influences motivation, pleasure and attention

Question 25

Effect of glutamine

Answer 25

-cognitive functioning, memory and learning -too much is dangerous and leads to cellular death so is associated with some diseases and brain injuries eg. Alzheimer's

Question 26

What is an agonist drug

Answer 26

A drug with chemical properties similar to a neurotransmitter and mimics its effect by binding to receptors to excite the neuron so more of the natural NT us released

Question 27

Example of agonist

Answer 27

cocaine and dopamine

Question 28

What is an antagonist?

Answer 28

reduces/stops the effect of an NT as it binds to receptor site to stop/slow passage of message

Question 29

Example of antagonist

Answer 29

Curare (poison) is antagonist for NT acetylcholine

Question 30

What is another way that drugs work? (3)

Answer 30

-can block reuptake of NT from synapse so NT stays in gap which increases its action -stops NT being synthesised -stops NT being released

Question 31

How does alcohol work?

Answer 31

blocks serotonin receptors which has calming effects, so we become merry

Question 32

What parts of the brain are affected when alcohol wears off?

Answer 32

low mood caused: prefontal cortex (decision making), amygdala (controls emotions), can make us aggressive

Question 33

How does nicotine work?

Answer 33

-affects dopamine receptors, causing a release of dopamine pleasure -excess dopamine means the brain shuts off dopamine receptors in an attempt to balance

Question 34

Why do people get addicted to nicotine?

Answer 34

low dopamine activity leads to nicotine craving to boost it

Question 35

How does cocaine work?

Answer 35

-blocks dopamine reuptake -therefore dopamine remains in synapse so can reattach to receptor and cause pleasure response again

Question 36

How does cannabis work?

Answer 36

-ingredient THC binds to cannabinoid receptors -THC inhibits release of neurotransmitter GABA, leading to increased dopamine levels

Question 37

What is GABA?

Answer 37

NT that blocks receptors and inhibits release of dopamine (cannabis inhibits GABA which means dopamine is released)

Question 38

How does heroin work?

Answer 38

-acts at opioid receptor sites in brain to release more dopamine -morphine binds to receptors to reduce inhibitory effect of GABA on dopamine neurons -higher dopamine activity and increased release into synapse -continual stimulation of dopaminergic reward pathway results in feelings of euphoria

Question 39

Short term effects of heroin

Answer 39

-calmed chill feeling as it floods endorphin receptors -activates reward system and good feelings as dopamine is released

Question 40

Long term effects of heroin

Answer 40

the brain adapts to high levels of dopamine and slows down its natural production, explaining why higher doses are needed

Question 41

Symptoms of taking heroin

Answer 41

-small dose causes feelings of warmth -large dose causes sleepiness and relaxation -pleasure and pain reduction -dry mouth, heavy limbs followed by slowing of mental functions, breathing and heart rate

Question 42

How do amphetamines work?

Answer 42

-block reuptake of NTs, meaning euphoria lasts longer -noradrenaline, serotonin and dopamine quickly released into brain -dopamine neurons may be excited via glutamate neurons as the two are interlinked

Question 43

describe amphetamines and dopamine

Answer 43

-increased release of dopamine from axon terminal -blocks dopamine reuptake -dopamine stored in vesicles in synapse or destroyed by enzymes -causes euphoria

Question 44

Short term effects of amphetamines

Answer 44

-the 3 neurotransmitters cause reward, pleasure, adrenaline all at once -euphoric effects are intense eg, feeling powerful -reduced fatigue -high heart rate and blood pressure

Question 45

Long term effects of amphetamines

Answer 45

-depression like symptoms when euphoria wears off which may cause and individual to become dependent -dopamine receptors become damaged/desensitised which causes addiction as more dopamine is required to stimulate neuron

Question 46

Physical long term effects of amphetamines

Answer 46

-extreme weight loss -dental problems -regular infections -risk of stroke

Question 47

Evaluate CNS as a good explanation Strengths

Answer 47

-high reliability as lab experiments can be replicated easily as they are artificial, eg. PET scans involve gamma rays being recorded on scanner -high validity as objective methods were used-Diana Marinez et al used PET scans to demonstrate how heroin changed dopamine receptors in rats

Question 48

Evaluate CNS as a good explanation Weaknesses

Answer 48

-limitation: reductionist because the effects of recreational drugs are reduced down to the release of a hormone -comparison: social approach better explains situational and personal factors that cause on individual to first take/continue to take a drug