Week 11 A2 Biology and Depression

1. Biological Explanation
• Complete the
worksheet revising
the biological
approach.

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3. Lesson Objectives
By the end of the lesson you …
• Must be able to define (AO1) the central nervous
system, synapse, neurones and
neurotransmitters.
• Must be able to describe (AO1) how the synapse,
receptors, neurons and neurotransmitters pass
‘messages’
• Should be able to describe (AO1) and evaluate
(AO2) the biological approach to understanding
depression.

4. 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?

6. ?
?
?
Biological
Approach

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

8. 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.

9. 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.

10. 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’.

12. The
Neurone

13. The Synapse

14. 1
Vesicles release neurotransmitter
into synaptic cleft

15. 2
Neurotransmitter binds to
receptors & activates them

16. 3
Excess neurotransmitter is taken
up by the pre-synaptic neurone

17. 4
Enzymes are released to break down
the remaining neurotransmitter

18. 5
Vesicles are replenished with new
& reused neurotransmitter

19. Prozac
Selective Serotonin Reuptake Inhibitor

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

21. 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."

22. 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.

23. Describe how neurotransmitters
work differently in a person with
depression. Include an explanation
of synaptic transmission in your
answer and give a reason for the
difference.

24. • Must be able to define (AO1) the central nervous
system, synapse, neurones and neurotransmitters.
• Must be able to describe (AO1) how the synapse,
receptors, neurons and neurotransmitters pass
‘messages’
• Should be able to describe (AO1) and evaluate (AO2) the
biological approach to understanding depression.

25. Emailing a friend …
Imagine your are emailing a friend who
has depression and who does not know
much about psychology and describing
to them how the biological approach
would explain their depression.

26. Lesson Objectives
By the end of the lesson you …
• Must be able to compare (AO2) the biological
and cognitive explanations of depression.
• Should be able to mark a 12 mark question
and give feedback on it.

27. There are many explanations for depression
including biological ones.
Describe one explanation for depression and
compare this with one other explanation.
Comparisons include considering similarities
and/or differences.
[12]
*in the exam they cannot specifically name depression.

28. • Must be able to compare (AO2) the
biological and cognitive explanations of
depression.
• Should be able to mark a 12 mark question
and give feedback on it.

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