Week 11 AS Biological Psychology

1. Pinky and The Brain …
1.
2.
3.
4.
5.
6.
How many brain cells does
an average brain contain?
What percentage of the
bodies energy does the
brain use?
How much does a brain
weigh?
What percentage of our
brain do we use?
How many times do our
brain cells fire a second?
How many times do
synapses send information
every second?

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3. Lesson Objectives
By the end of the lesson you …
• Must be able to define (AO1) the biological
approach.
• Must be able to define (AO1) the central
nervous system, synapse, neurones and
neurotransmitters.

4. “The human brain is not like other organs of
the body in that looking at its structure does
not reveal anything about how it functions. We
can see that the wall of the small intestine
acts as an absorptive surface; the heart as a
pump. The brain, however, is a large mass of
cells and fibres which, no matter how clearly
we look at it, gives no indication of how we
think, speak and remember.”
Parkin, 2000

10. Approach
Theories
Studies
Methods
Biological Approach
Biological Theory of Gender
Development
Money (1975)
Raine (1997)
Twin / adoption studies
MRI / PET scanning
Lab Experiments on Animals

11. How chemical
activity
mediates out
behaviour.
Genetic
Influences
over our
behaviour
Biological
Approach
Hormonal
Influences
over our
behaviour

12. How chemical
activity
mediates out
behaviour.
Neurotransmitters
• One way messages are passed within the brain
is by neurotransmitters.
• These are chemicals that pass from neuron to
neuron.
• Between neurones there are gaps called
synapses.
• If the receptors of one neuron are set to
receive the neurotransmitters of another,
then the message continues.

13. Genetic
Influences
over our
behaviour
Genetic Influences
• Genes are passed on from parents to children
and they govern behaviour as well as physical
characteristics. Children receive (approx.) half
their genes from their fathers and half from their
mothers.
• The human genome has recently been decoded,
which means that all genes have been identified.
• Does not mean the function of each gene is
known because it is often the combination or the
position of genes that leads to certain
characteristics, rather than one particular gene.

14. Hormonal
Influences
over our
behaviour
Hormonal Transmission
• Hormones are another way
messages are passed around the
body.
• These send messages more slowly
than neurotransmitters and are used
for different purposes.
• Hormones have a large part to play in
our development as either male or
female – for example, ANDROGENS
are ‘male’ and OESTROGEN is
‘female’.

15. Consolidation Question
Describe what is meant by the biological
approach, giving at least 2 features of the
approach in your answer.
(6 marks)
10 minutes

16. The biological approach looks at chemical
activity in the brain, including how
neurotransmitters act at synapses to enable
messages to be transmitted. Eg …
Another way messages are transmitted is
through hormones which act slower than
neurotransmitters. Eg …
The biological approach includes an
evolutionary perspective, which examines how
characteristics are inherited via genes. Eg …

17. Central
Nervous
System
Hormones
Neuron
Brain
Laterlisation
Synapse
Neurotransmitters

18. The Central
Nervous System
The central nervous
system is made up of the
brain and spinal cord. The
brain functions to receive
nerve impulses from the
spinal cord and cranial
nerves. The spinal cord
contains the nerves that
carry messages between
the brain and the body.

19. A neuron (or neurone or nerve cell) is an electrically
excitable cell that processes and transmits information
by electrochemical signaling, via connections with other
cells called synapses.

20. Neurones
Neuronal cell
bodies
Axons
Synapses occur
at the junctions

21. Synapses
• Neurones transmit signals electrically along
their axons.
• The synapses (junctions between neurones)
transmit signals chemically.

22. Synapse
Vesicles filled with
neurotransmitter
Synaptic cleft
Location of
receptors (postsynaptic density)

23. Neurotransmitters
Information is carried by
biochemical substances
called
neurotransmitters. The
terminal buttons and the
dendrites of other
neurons do not touch, but
instead pass the
information containing
neurotransmitters through
a synapse.

24. Brain Lateralisation
• The brain has many parts and
is in two halves or
hemispheres joined by the
CORPUS CALLOSUM.
• It is thought females use both
halves of their brain more
than males, and males are
more right-brain dominant.
• BRAIN LATERALISATION is the
term used when considering
the two halves of the brain
separately.

25. Central
Nervous
System
Hormones
Neuron
Brain
Laterlisation
Synapse
Neurotransmitters
Page 2 & 3

26. • Must be able to define (AO1) the biological
approach.
• Must be able to define (AO1) the central nervous
system, synapse, neurones and
neurotransmitters.

27. Define (without notes)
•
•
•
•
•
neurone
neurotransmitter
gene
synapse
CNS

28. Define (without notes)
• neurone
– a nerve cell that sends electrical impulses
• neurotransmitter
– a chemical released at the end of the neurone to
pass a message on to another neurone.
• gene
– units of information that are inherited.
• synapse
– the space between two neurones which is crossed
by neurotransmitters.
• CNS
– central nervous system – the brain and spinal cord
which organise communication around the body.

29. Lesson Objectives
By the end of the lesson you …
• Must be able to describe (AO1) how the
synapse, receptors, neurons and
neurotransmitters pass ‘messages’
• Must be able to describe (AO1) the
components of a neuron.

30. The
Neurone

31. The Synapse

32. 1
Vesicles release neurotransmitter
into synaptic cleft

33. 2
Neurotransmitter binds to
receptors & activates them

34. 3
Excess neurotransmitter is taken
up by the pre-synaptic neurone

35. 4
Enzymes are released to break down
the remaining neurotransmitter

36. 5
Vesicles are replenished with new
& reused neurotransmitter

37. Prozac
Selective Serotonin Reuptake Inhibitor

38. Illustration 1 shows how this works in a
healthy nerve transmission process

39. Illustration 2 shows the process when Major Depression is present.
Note that fewer Serotonin molecules are present in the synaptic cleft
and hence fewer make it to the next neuron to make it "fire."

40. Illustration 3 shows how an SSRI drug blocks the reuptake of Serotonin thus
causing the concentration in the synaptic cleft to be increased. Consequently
more serotonin makes it to the receptor sites on the next nerve cell and the
functioning returns to normal.

41. Describe how neurotransmitters
work. Include an explanation of
synaptic transmission in your
answer and give one example to
illustrate.
(8 marks)

42. • Must be able to describe (AO1) how the synapse,
receptors, neurons and neurotransmitters pass
‘messages’
• Must be able to describe (AO1) the components
of a neuron.

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