Transcript Biological Approach

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?
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
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.
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.
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.
Parts of the brain and spinal cord
The Brain
Continued:
• Find out the location and function of the following brain
parts:
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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.
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?
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
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
Different parts of the neuron
– Cell body
– Axon
– Dendrites
– Terminal buttons
How brain
messages are sent
using neurons
Messages in the brain are sent by
using electrical impulses and
chemicals called neurotransmitters
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
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
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
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
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
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!
Synaptic
Gap
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
How Synapses work
• You will need notes on how messages are
passed via neurotransmitters
• http://www.youtube.com/watch?v=HXx9qlJet
SU
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.
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.
Extension
• How do you think drugs work?
Exam question
• Describe the process of synaptic transmission.
(6 marks)
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)
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
Recreational drugs
• How do recreational drugs affect the CNS?
• In pairs, explain to others the role of
recreational drugs on the CNS.
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.
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.
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 tailormade 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.
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.
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.
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
Classwork
• Research how one
particular drug affects
the CNS.
• Any stimulant (caffeine,
nicotine, amphetamine,
cocaine), any opiates
(painkillers), any
sedative (alcohol),
Exam question
• Describe the effect of a
recreational drug on the
transmission process in
the CNS (8 marks)
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 wellknown stimulant.
Tea (left) and cocaine (right)
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).
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.
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
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???????