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Biological Approach Introduction to Biological Psychology CSN and neurotransmission The effect of recreational drugs

Biological Approach Introduction to Biological Psychology CSN and neurotransmission The effect of recreational drugs

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Page 2: Biological Approach Introduction to Biological Psychology CSN and neurotransmission The effect of recreational drugs

Biological psychology

• What is biological psychology? • What do we need to know?• What sort of research methods do you think

are utilised? Why?

Page 3: Biological Approach Introduction to Biological Psychology CSN and neurotransmission The effect of recreational drugs

Objectives - To get an A grade I need to be able to:

• Name and describe the function of a number different brain areas

• Define the CNS

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CENTRAL NERVOUS SYSTEM• The Nervous System has 2 main parts – the Central Nervous

System (CNS) and the Peripheral Nervous System.• The CNS consists of the brain and the spinal cord. • The brain is within the skull and the spinal cord is within the

vertebrae.

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CNS• The CNS is the main control centre of the body—it takes in

sensory information, organizes and synthesizes data, then provides direction for motor output to the rest of the body.

• The CNS is made up of the brain, brain stem, and spinal cord.• The brain is the main data centre of the body and consists of the

cerebrum which regulates higher level functioning such as thought, and the cerebellum which maintains coordination.

• The brain stem includes the midbrain, pons, and medulla, and controls lower level functioning such as respiration and digestion.

• The spinal cord connects the brain and the body's main receptors, and serves as a conduit for sensory input and motor output.

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Key terms• spinal cord A thick, whitish cord of nerve tissue which is a major

part of the central nervous system. It extends from the brain stem through the spine, with nerves branching off to various parts of the body.

• Cerebellum Part of the hindbrain in vertebrates. In humans it lies between the brainstem and the cerebrum, and plays an important role in sensory perception, motor output, balance and posture.

• Cerebrum In humans it is the largest part of the brain and is the seat of motor and sensory functions, and the higher mental functions such as consciousness, thought, reason, emotion, and memory

• brain stem The part of the brain that connects the spinal cord to the forebrain and cerebrum.

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Parts of the brain and spinal cord

The Brain

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Continued:• Find out the location and function of the following brain parts:

• Parietal lobe• Frontal lobe• Occipital lobe• Temporal lobe• Cerebral cortex• Pre-frontal cortex• Corpus callosum• Ventricles• Thalamus• Pituitary gland• Hypothalamus• Brain stem

Stretch and challenge:Find out about 5 other brain structures and their functions.

Stretch and challenge:Research 1 example of brain injury and how this has affected the individual’s functionality.

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What happens when brains get ‘broken’?

• Read the two articles ‘Phineas Gage and the effect of an iron bar through the head on personality’

• and ‘'There was a lot more to fix than I thought‘.

• What does these tell us about the structures and functions of the brain?

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Objectives – To get an A grade I need to be able to:

• Describe the structure of a neuron and its role• Describe the function of a neurotransmitter • Describe synaptic transmission

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What is a neuron?

• Cell in nervous system which sends processes and sends information within the body.

• Sensory neurons– Receive messages from senses

• Touch• Light • Sound

• Motor neurons– Muscle movement

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Different parts of the neuron

– Cell body– Axon– Dendrites– Terminal buttons

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How brain messages are sent

using neurons

Messages in the brain are sent by using electrical impulses and

chemicals called neurotransmitters

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How brain messages are sent using neurons

– Step one: • In one neuron, in the cell

body, an electrical impulse (can also be called an action impulse) is triggered. This travels down the axon to the end.

• Make the cell body of the neuron

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How brain messages are sent using neurons

– Step two:• At the end of the axon and the terminal branches are

the terminal buttons here the electrical impulse releases a chemical called a neurotransmitter

• Make the axon and the terminal branches of the neuron

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How brain messages are sent using neurons

• Neurotransmitters are chemical messengers that act between the neurones in the brain. This allows the brain to process thoughts and memories.

• Eg. Serotonin is a neurotransmitter that produces a feeling of happiness!

• Make a tiny neurotransmitter

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How brain messages are sent using neurons

– Step three:• This neurotransmitter now has to cross a gap called a

synapse or a synaptic gap to get to the dendrites on the next neuron to continue the message. The neurotransmitter can get lost in the gap.

• Add the dendrites to the cell body

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How brain messages are sent using neurons

– Step four:• If the receptors at the dendrites of the next neuron are

suitable to receive the neurotransmitter in the gap it will get picked up by them. LOCK AND KEY

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How brain messages are sent using neurons

– Step five:• The neurotransmitter changes the

chemical balance (this is called the synaptic transmission) at the receptor which sets off an electrical impulse whilst the neurotransmitter drops back into the synaptic gap. And the process starts all over again!

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Synaptic Gap

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Lock and Key

• Receptors at a dendrite will be a certain shape (a lock) which can only take a certain neurotransmitter (key)

• Lock and Key diagram

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How Synapses work

• You will need notes on how messages are passed via neurotransmitters

• http://www.youtube.com/watch?v=HXx9qlJetSU

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Page 24: Biological Approach Introduction to Biological Psychology CSN and neurotransmission The effect of recreational drugs

Place the following in the correct order• The axon terminal of one neuron reaches to the dendrites of

another.• Dendrites surround the nucleus which is connected to a long

extension called an axon, which reaches the an axon terminal.• On one side, at the dendrites, there are receptors of a certain

shape, prepared to receive the neurotransmitter from another neuron.

• If the neurotransmitter fits the receptor the message is passed on; if it does not, the message is blocked.

• Between the terminal and the dendrites, there is a gap called a synapse.

• A neurotransmitter travels down the pre synaptic neuron, across the synapse and binds in a lock and key effect to a receptor on the post synaptic neuron. A neuron is made up of dendrites, a nucleus, an axon and an axon terminal.

Page 25: Biological Approach Introduction to Biological Psychology CSN and neurotransmission The effect of recreational drugs

Answers • A neuron is made up of dendrites, a nucleus, an axon and an axon terminal.• Dendrites surround the nucleus which is connected to a long extension

called an axon, which reaches the an axon terminal.• The axon terminal of one neuron reaches to the dendrites of another.• On one side, at the dendrites, there are receptors of a certain shape,

prepared to receive the neurotransmitter from another neuron.• Between the terminal and the dendrites, there is a gap called a synapse.• A neurotransmitter travels down the pre synaptic neuron, across the

synapse and binds in a lock and key effect to a receptor on the post synaptic neuron.

• If the neurotransmitter fits the receptor the message is passed on; if it does not, the message is blocked.

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Extension

• How do you think drugs work?

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Exam question

• Describe the process of synaptic transmission.(6 marks)

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Exam Questions

• Describe the Central Nervous System (4 marks)

• What is a neuron? (2 marks)• What is a neurotransmitter? (2 marks)• What is a synapse? (2 marks)

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Objectives – To get an A grade I need to be able to:

• Describe the effect of recreational drugs on the transmission process in the CNS

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Recreational drugs

• How do recreational drugs affect the CNS?• In pairs, explain to others the role of

recreational drugs on the CNS.

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How do drugs affect your brain?

Why does a cup of coffee wake you up, and aspirin stop your headache? Many drugs work by copying or blocking the effects of naturally occurring chemicals in your brain.

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What is a drug?

• A drug is any chemical you take that affects the way your body works. Alcohol, caffeine, aspirin and nicotine are all drugs. A drug must be able to pass from your body into your brain. Once inside your brain, drugs can change the messages your brain cells are sending to each other, and to the rest of your body. They do this by interfering with your brain's own chemical signals: neurotransmitters that transfer signals across synapses.

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What is a synapse?• When a nerve impulse reaches

the synapse at the end of a neuron, it cannot pass directly to the next one. Instead, it triggers the neuron to release a chemical neurotransmitter. The neurotransmitter drifts across the gap between the two neurons. On reaching the other side, it fits into a tailor-made receptor on the surface of the target neuron, like a key in a lock. This docking process converts the chemical signal back into an electrical nerve impulse.

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Altering your mind?• Some drugs interfere with

neurotransmitters in the brain. These 'mind-altering' drugs change our interpretation of the world, our behaviour, and our mood. For example, cannabis affects neurons releasing acetylcholine, noradrenaline and dopamine.

• LSD is a combination of an artificial acid and a natural molecule found in the fungus Claviceps purpurea (Ergot). LSD mimics serotonin action in the brain, which seems to explain its hallucinogenic effects.

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What makes drugs addictive?

• Doctors call a drug addictive if it makes you dependent on the drug. Unpleasant withdrawal symptoms appear unless you take the drug. Addictive drugs also make you crave them - you have an overwhelming urge to continue taking the drug, even after withdrawal symptoms have disappeared.

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Why are some drugs addictive?

• Scientists think that all addictive drugs activate the brain's 'reward system', by increasing the release of the chemical dopamine from neurons in key areas of the brain. Dopamine release occurs after pleasurable experiences, for example after food or sex, but can also be induced by some drugs. Drugs that artificially increase dopamine release in this way may cause craving for more. It is possible that some people may have a genetic tendency to make them develop drug addictions extremely rapidly.

Dopamine releasing neurons

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Classwork

• Research how one particular drug affects the CNS.

• Any stimulant (caffeine, nicotine, amphetamine, cocaine), any opiates (painkillers), any sedative (alcohol),

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Exam question

• Describe the effect of a recreational drug on the transmission process in the CNS (8 marks)

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What are stimulants?• Stimulants are drugs that make

you feel more alert. Caffeine, found in tea, coffee and chocolate, is one example. Many plants contain naturally occurring stimulants (probably to deter invading insects) that in humans make the brain and body more active. Many stimulants, such as nicotine and cocaine, are harmful and addictive. Amphetamine, which was first made a century ago, is another well-known stimulant.

Tea (left) and cocaine (right)

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What are opiates?• Opiates, originally derived from

the opium poppy, have been used for thousands of years for both recreational and medicinal purposes. The most active substance in opium is morphine - named after Morpheus, the Greek god of dreams. Codeine, a less powerful drug, is also found in opium. Both these opiates relieve pain, relax muscles and cause drowsiness. All opiates mimic your body's own painkillers. Morphine is a very powerful painkiller, but it is also very addictive.

All opiates originally derived from the opium poppy (Papaver somniferum).

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How do painkillers work?

• When part of your body is injured, special nerve endings send pain messages back to your brain. Painkilling drugs interfere with these messages, either at the site of the injury, in the spinal cord or in the brain itself. Many painkillers are based on one of two naturally occurring drugs: aspirin and opiates. Aspirin uses a chemical found in willow bark, used by the Ancient Greeks to relieve pain. Opiates all work in a similar way to opium, which is extracted from poppies.

Painkillers interfere with the pain messages sent to your brain.

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What are sedatives?• Sedatives are drugs that calm you

down. The oldest known sedative is probably alcohol, used for thousands of years. Surgeons even used it as a general anaesthetic before the arrival of ether and chloroform. Barbiturates were synthesised in the 1890s and abused widely by the 1900s. The search for safer sedative and anxiety-reducing drugs began after the Second World War, eventually resulting in the discovery of a family of drugs known as benzodiazepines, which include Valium.

Sedatives are drugs that calm you down

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Links to Issues and Debates

Ethics – e.g. studying aggression and how findings are used; in the research itself such as issues of confidentiality and informed consent.Reductionism – e.g. focusing specifically on aggression when studying the brain.Nature-nurture – e.g. brain localisation in aggression and environmental influences on aggression.The use of psychological knowledge within society – e.g. understanding causes of aggression, in order to perhaps deal with them.

Can you identify where the issues and debates were in today’s lesson???????

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