THE BIOLOGICAL APPROACH - THE BRAIN

Question 1

What is the soma?

Answer 1

Contains the nucleus which houses the genetic material for that particular neurone, and also contains other materials that allows the cell to function (eg mitochondria)

Question 2

What are dendrites?

Answer 2

Attached to the cell body and attaches to the adjacent neurones
Receives information/chemical messages from the other neurones in order to trigger an action potential

Question 3

What is an axon?

Answer 3

An extension of the cell body that passes the electrical impulse towards the axon terminals
Around the outside are layers of fatty deposits called myelin sheath that acts as insulation for the electrical impulse (speeds up transmission)

Question 4

What are axon terminals?

Answer 4

Located at the end of the axon
Nerve impulses are passed to another neurone, or to a muscle or gland
They are bulb shaped structures that contain tiny sacs called vesicles which store neurotransmitters

Question 5

What are nodes of (x) ranvier?

Answer 5

Gaps between schwann cells that make up the myelin sheath
Uninsulated sections of the axon therefore capable of generating electrical activity, effectively acting as repeater stations boosting the electrical impulse

Question 6

What is the effect of alcohol on the brain?

Answer 6

It stops the message from being sent as it keeps the neurone polarised (it blocks the sodium gateways so sodium can’t alter the electrical charge)

Question 7

What happens at the synapse?

Answer 7

Chemicals pas from the axon to the terminal buttons
Synapse vesicles, filled with neurotransmitters in the terminal button, fuse with the nerve ending membrane resulting in the release of neurotransmitters
Presynaptic receptors detect the amount of neurotransmitters in the terminal button, and stop releasing them if there aren’t many
Neurotransmitters lock perfectly to the postsynaptic receptors and carry on messages through the next neurone

Question 8

What are neurotransmitters?

Answer 8

Act in the brain and the central nervous system, by passing messages across neurones and synapses
Excitatory: cause action potentials and generate an electrical message (eg dopamine)
Inhibitory: block/prevent the action of neurones (eg GABA)

Question 9

What is dopamine?

Answer 9

Responsible for reward driven learning as it’s linked to pleasure
Helps us to make decisions as it focuses our attention on the possible rewards
Also linked to emotion, control of movement and cognition
Many addictive drugs act directly on the dopamine reward pathways which creates the positive feeling
High levels are linked to schizophrenia, and low levels with behaviour disorders
There are five dopamine receptors

Question 10

What is noradrenalin?

Answer 10

Associated with emotion, especially mood control
Involved in functions like sleeping, dreaming and learning
Linked to the fight or flight response

Question 11

What is serotonin?

Answer 11

Associated with emotion and mood control
Reduced levels are linked to aggression and depression
There are fifteen serotonin receptor sites

Question 12

What is acetylcholine?

Answer 12

Stimulates muscle contractions and has a key function in motor control and movement
Also necessary for memory and other cognitive functions (eg attention and alertness)

Question 13

What are hormones?

Answer 13

Chemical messengers but are released by the endocrine system and effect organs and target cells
Have a much longer effect than neurotransmitters (eg puberty)
Oxytocin is a neurotransmitter and hormone, which encourages lactation when a hormone and responsible for love and bonding when a neurotransmitter

Question 14

What are genes?

Answer 14

Units of information we inherit from our parents
Recessive: need two copies of the cell to inherit it
Dominant: only need one copy of the cell to inherit it
We have 22,000 genes which results in the curse of variables (if looking for a particular gene, may see a relationship/pattern when its random)

Question 15

What are the four lobes in the brain?

Answer 15

Frontal lobe, temporal lobe (bottom), parietal love (top), occipital lobe (back)

Question 16

What is the parietal lobe?

Answer 16

Responsible for body sensations, integrating sensory information and language processing

Question 17

What is the frontal lobe?

Answer 17

Responsible for planning movements, some aspects of memory, inhibition of inappropriate behaviours
Contains dopamine sensitive neurones so gives us the ability to make decision
It extends into the prefrontal cortex which receives all the sensory information and links to the limbic system

Question 18

What is the occipital lobe?

Answer 18

Responsible for vision

Question 19

What is the temporal lobe?

Answer 19

Responsible for understanding spoken language, visual processing, recognition and emotional responses, also contains the hippocampus

Question 20

Who supported the role of the temporal lobe?

Answer 20

Kluber and Bucky found that previously aggressive monkeys failed to display normal fears and anxieties after temporal lobe damage

Question 21

What is the limbic system?

Answer 21

Surrounds the brain stem and is responsible for co-ordination and movement at the base of the brain
Important for basic survival drives
Contains the hippocampus, hypothalamus, cingulate gurus, the midbrain and the prefrontal cortex

Question 22

What is the hippocampus?

Answer 22

Responsible for memory and contains the amygdala
The amygdala which is the centre for primitive emotional behaviour and also integrates internal and external stimuli and every sensory modality input which gives us an instinctive feeling
Supported by Charles Whitman and Urbach-Wiethe syndrome

Question 23

What is the hypothalamus?

Answer 23

Controls basic bodily functions (eg thirst, hunger, body temperature)
Can signal to release testosterone from glands

Question 24

What is the midbrain?

Answer 24

Contains PAG (periaqueductal gray) which links the amygdala and hypothalamus with the prefrontal cortex
Plays a role in the modulation of pain in defensive behaviour
Coordinates/integrates behaviour to perceived external threat/stressors

Question 25

What is the prefrontal cortex?

Answer 25

Front part of the brain which occupies ⅓ of the entire volume of the cortex Influential in governing social interactions Linked to rationality, doesn’t develop fully until 20s which could explain why teenagers are more risk taking Supported by Phineas Gage

Question 26

Who was Phineas Gage?

Answer 26

Experienced a horrific industrial accident that severely damaged his prefrontal cortex His language, intellectual capabilities and movement were unaffected however his personality significantly changed as he became more angry, impulsive and aggressive Died 11 years later, but was returning to his previous personality showing brain plasticity

Question 27

Who was Charles Whitman?

Answer 27

Got hold of a rifle and went to the top of a tower, where he shot a lot of people after stabbing his mother and wife Later discovered he had a large tumour that was pushing against his amygdala which affected his emotional responses

Question 28

What is Urbach-Wiethe syndrome?

Answer 28

Brain disease which leads to atrophy of the amygdala (decays and shrivels) The group without the disease could remember the gory details of a traffic accident, as they created an emotional response to it, however those with the disease couldn’t

Question 29

What is the charge inside and outside of the neurone?

Answer 29

The inside of a neurone is negatively charged due to having negatively charged chloride ions and large negatively charged protein molecules The outside of a neurone is positively charged due to large amounts of sodium, and a smaller amount of potassium

Question 30

What is resting potential?

Answer 30

The state of the neurone is in when it’s polarised and it’s ready to send a message but it’s not sending it There is 10x as much sodium outside the membrane than inside (trying to push inside) There is 20x more potassium inside the membrane than outside (trying to push out) The membrane is semi permeable with gaps called sodium potassium gateways, and there’s an operating sodium potassium pump that regulates/controls the equilibrium

Question 31

What is action potential?

Answer 31

The state of the neurone is in when it’s polarised and it’s ready to send a message but it’s not sending it There is 10x as much sodium outside the membrane than inside (trying to push inside) There is 20x more potassium inside the membrane than outside (trying to push out) The membrane is semi permeable with gaps called sodium potassium gateways, and there’s an operating sodium potassium pump that regulates/controls the equilibrium

Question 32

What is the effect of recreational drugs?

Answer 32

When you take drugs it increases the levels of dopamine in the brain and therefore you’re more likely to repeat the behaviour (leads to addiction) Down regulation - become less sensitive to the neurotransmitter Up regulation - become more sensitive to the neurotransmitter Some drugs also release serotonin (eg ecstacy)

Question 33

What are arguments for addiction being biological?

Answer 33

Drugs increase the amount of dopamine which rewards you, so repeat behaviour to get the reward again Olds and Milner attached electrodes to the dopamine centres of monkeys and rats brains and they had lever to self administer dopamine The rats pressed the lever 2000 times an hour, and the monkeys 8000 times an hour (until they collapsed from exhaustion) Suggests that dopamine plays a major role in addiction Noble discovered that people with the a1 version of a gee produce less dopamine so turn to drugs for more dopamine Suggests that addiction is biological

Question 34

What are arguments against addiction being biological?

Answer 34

Only 10% of those who take cocaine get addicted Alexander Came up with luxury rat park and basic rat park, both with morphine infused water Rats in luxury rat park hardly pressed the lever whereas basic rat park rats pressed it loads Suggests addiction is more social than biological Supported by the Vietnam war where the soldiers took heroin for pain but once back home only 10% were addicted (environment impacts addiction) Siegel et al Three groups of rats, first group never had done heroin and the two others had The first group were given 15mg and 96% died The second group were given 15mg in the same location and 32% died This group were given 15mg in a new location and 64% died Supports that addiction is situational

Question 35

What is the biological key question?

Answer 35

What is an effective way and reason for using biological treatments for chronic drug addiction?

Question 36

Why is the biological key question relevant to today’s society?

Answer 36

Substance abuse is a major problem in society, as addicts are unable to work, cost the NHS and the individual money, impact the family and they often commit crime About ⅓ of addicts have been claiming benefits for at least ten years to pay for drugs

Question 37

What is a biological treatment of addiction?

Answer 37

Methadone - a synthetic opiate that replaces heroin at the synapse, allowing the addict to function normally Avoids withdrawal symptoms and is taken orally Lasts 24 hours so only needed once a day allowing time for the addict to recover socially and psychologically Amount is gradually decreased enabling the addict to recover fully Olds and Milner support that addiction is biological therefore a biological treatment is necessary

Question 38

What are criticisms of the biological treatment of addiction?

Answer 38

It partially blocks the ‘rush’ so is less desirable Addicts stay on it for a while so no progress is made Overdosing is still possible It doesn’t tackle the underlying causes of addiction, just the symptoms

Question 39

What are non-biological treatments for addiction?

Answer 39

Any treatment should tackle the biological, social and psychological factors (eg CBT, psychoanalysis, behavioural therapies, self-help groups etc) However they still experience withdrawal due to down regulation and brain plasticity meaning the addict is dependent on it Addicts socially associate people, places and times with drug taking and therefore to recover they need to dissociate these things, which biological treatments don’t Alexander supports that addiction is social showing that treatments should address this as well as biological factors