Download Sympathetic nervous system

Review of Biological Approach
Assumptions
Genetic basis
of behaviour
Twin studies
Concordance
rates
Genotype &
Phenotype
Evolutionary
behaviour
Strengths
Weaknesses
Twin Studies adoption studies
and correlation
How they contribute to our
understanding of the learnt innate
debate
Mini-Plenary
What is wrong with heritability studies?
Twin studies.
MZ twins reared together
often treated the same.
Difficult to measure the
true impact of
environment.
DZ twins reared in the same Underestimates the
environment often
importance of
treated differently.
environment.
Twins reared apart – rare –
often brought up in close
proximity
Biological Approach
Strengths
Scientific – uses experimental procedures
Evidence for the nature side of nature-nurture
debate
Useful applications to understanding many
disorders; down’s syndrome, bipolar disorder,
autism.
Biological approach
Weaknesses
Reductionist – explains ALL behaviour in terms of
genes, nerves or chemicals
Over-simplistic – fails to appreciate the
environment
Ethical issues – genetic manipulation? Selective
breeding.
5.1 Biological Questions
1.
Describe what is meant by a concordance rate. (2 marks)
2.
What is the difference between a genotype and a phenotype. Give examples
in your answer. (4 marks)
3.
Outline the theory of evolution and give examples of how it influences our
behaviour. (4 marks)
4.
5.
Outline one assumption of the biological approach. (2 marks)
Rita and Holly are identical twins who were separated at birth. When they
finally met each other at the age of 35, they were surprised at how different
their personalities were. Rita is much more social and out-going than Holly.
Use your knowledge of genotype and phenotype to explain this difference in
their personalities. [4 marks]
6.
Outline and evaluate the biological approach to explaining behaviour. (12
marks)
7.
Describe one strength and one weakness of the biological approach. (4 marks)
Darwin
https://www.youtube.com/watch?v=2d_FkpVkQo
Sperry
All that is psychological is first physiological.
6.1 Influence of biological structures
on behaviour.
Central Nervous System (CNS)
The central nervous system is made up of
the brain and the spinal cord.
The biological approach focuses on the
brain as it controls our behaviour.
Human Nervous System
Draw on
board functions
Human Nervous
System
Peripheral
nervous system
Autonomic
nervous system
Sympathetic
nervous system
Somatic nervous
system
Central nervous
system
Brain
Parasympathetic
nervous system
https://www.youtube.com/watch?v=zeo19WVQ47w
Spinal cord
The nervous system
• Biopsychologists assume that behaviour and
experiences are caused by activity in the
nervous system
• The nervous system is a specialised network of
cells in the human body and is our primary
internal communication system
• It has two main functions:
 To collect, process and respond to information in the
environment
 To co-ordinate the working of different organs and cells
Human
nervous
system
Peripheral nervous
system (PNS)
Autonomic
nervous system
Somatic nervous
system
Sympathetic
nervous system
Parasympathetic
nervous system
Central nervous
system (CNS)
Brain
Spinal cord
The major sub-divisions of the human nervous system
Human nervous
system
Peripheral nervous
system (PNS)
Autonomic nervous
system
Somatic nervous
system
Sympathetic
nervous system
Parasympathetic
nervous system
Central nervous
system (CNS)
Brain
Spinal cord
The major sub-divisions of the human nervous system
The central nervous system (CNS)
The CNS is made up of the
brain and the spinal cord
•The brain is the centre of all
conscious awareness. The brain’s
outer layer, the cerebral cortex, is
highly developed in humans
•The brain is divided in two
hemispheres
•The spinal cord is an extension of
the brain. It is responsible for reflex
actions
The CNS passes
messages to and
from the brain
and connects
nerves to the PNS
The peripheral nervous system (PNS)
The PNS transmits messages
via millions of neurons (nerve
cells), to and from the central
nervous system
The PNS is further subdivided into:
• the somatic nervous system (SNS)
• the autonomic nervous system (ANS)
The somatic nervous system
This is the part of the PNS that is responsible for
carrying sensory and motor information to and
from the spinal cord
The autonomic nervous system (ANS)
This governs vital functions
in the body such as
breathing, heart rate,
digestion, sexual arousal
and stress responses
The two main divisions of the ANS
The two main divisions of the autonomic
nervous system are:
• The sympathetic nervous system
• The parasympathetic nervous system
Their actions are mostly antagonistic - that is
they usefully work in opposition to each other
The opposing actions of the sympathetic and the
parasympathetic nervous system
Organ
Sympathetic nervous system
Parasympathetic nervous system
Gut
Slows digestion
Increases digestion
Salivary glands Inhibits saliva production
Increases saliva production
Heart
Increases heart rate
Decreases heart rate
Liver
Stimulates glucose production
Stimulates bile production
Bladder
Stimulates urination (relaxes the
Inhibits urination (contracting
bladder)
bladder)
Eye
Dilates pupils
Constricts pupils
Lungs
Dilates bronchi
Constricts bronchi
Generally,
maintains
and
conserves
body
energy
and
functions
Generally
prepares
the body
to expend
energy
for fight
or flight
Fight or flight response
• Anxiety and fear are actually important for
survival because they act as a mechanism to
protect the body against stress and danger.
• The sympathetic nervous system controls
what has been called the "Fight or Flight"
phenomenon because of its control over the
necessary bodily changes needed when we
are faced with a situation where we may need
to defend ourselves or escape.
Imagine…
• You are walking down a dark street at night by
yourself. Suddenly you hear what you suspect
are footsteps approaching you rapidly.
• What happens?
• Your sympathetic nervous system kicks in and
in an instant, your body is prepares itself for
either defence or escape.
Fight or flight?
• These changes enable the body to take action
and protect itself in dangerous situations,
either by running away or fighting – hence,
the fight or flight response.
When the ‘threat’ has passed…
• Now imagine that the footsteps belong to a good
friend who catches up to you and offers to walk
you home. You feel relief instantly, but your body
takes longer to adjust.
• In order to return everything to normal, the
parasympathetic nervous system kicks in.
• This system is slow acting, unlike its counterpart,
and may take several minutes or even longer to
get your body back to where it was before the
scare.
• These two subsystems are at work constantly
shifting your body to more prepared states
and more relaxed states.
• Every time a potentially threatening
experience occurs (e.g., someone slams on
their breaks in front of you, you hear a noise
in your house at night, you hear a loud bang, a
stranger taps you on the shoulder
unexpectedly), your body reacts.
The constant shifting between these two
systems keeps your body ready for your current
situation.
6.2 Structure and Function of Neurons
“Our deepest emotions are nothing
more than chemical equations”
Bullet with Butterfly Wings
(Smashing Pumpkins)
Neurons
Facts about Neurons …
• 100 billion neurons or nerve cells in the human nervous
system.
• Some are small and some are over 1 metre long.
• Neurons are nerve cells that transmit nerve signals to and
from the brain at up to 200 mph.
• A typical neuron has about 1,000 to 10,000 synapses (that
is, it communicates with 1,000-10,000 other neurons,
muscle cells, glands, etc.)
The Structure of Neurons
Neurons
Source: science photo library
Neuronal cell
bodies
Axons
Synapses occur
at the junctions
Motor Neuron
Carry messages away from the brain and spinal cord to the organs and muscles in the body.
CNS - PNS
Sensory Neuron
Carry messages from the receptors in the body to the brain and spinal cord.
PNS - CNS
Interconnecting/Relay Neuron
Transmits information from sensory neurons to motor neurons
Synapses
The gap between the end of one neuron and the dendrites of the next neuron.
Types of Neuron
• Use page 228 in your textbook to complete
the blanks on the sheet.
Structure
Function
Axon
The axon is the elongated fibre that extends from the cell body to the
terminal endings carries the nerve impulse away. The larger the axon,
the faster it transmits information.
Myelin sheath
Insulating layer – (fatty substance ) which increases speed of
transmission.
Axon Terminal
The terminal buttons are located at the end of the neuron and are
responsible for sending the signal on to other neurons.
Dendrite
are tree-like extensions at the beginning of a neuron
Large surface area covered with synapses.
Receive information from other neurons and transmit electrical
stimulation to the soma.
Synapse
At the end of the terminal button is a gap known as a synapse.
Neurotransmitters are used to carry the signal across the synapse to
other neurons.
Node of Ranvier
gaps between the myelin sheaths generated by different cells. At nodes
of Ranvier, the axon is uninsulated and therefore capable of generating
electrical activity.
Schwann Cells
Wrap around the Axon to form the myelin sheath
Activity: Reflex Arc
Construct a neural pathway for being hit on the
knee with a hammer!
Sensory
Neuron
Hammer
Knee
Interconnecting
Neuron
Motor Neuron
Synaptic Transmission
• Synaptic Transmission: the process by which
nerve impulses are carried across the small
gap, the synapse, between one neuron and
another. The nerve impulse is an electrical
signal which is carried by chemicals called
neurotransmitters.
• This happens at very high speed e.g. visual
information seems to be encoded within 50100 milliseconds of neuronal activity.
Synapses
• Neurons transmit signals electrically along
their axons
• The synapses (junctions between neurones)
transmit signals chemically.
Synapse
Source: neuroscience.wustl.edu
Vesicles filled with
neurotransmitter
Synaptic cleft
Location of
receptors (postsynaptic density)
Vesicles release neurotransmitter
into synaptic cleft
Neurotransmitter binds to
receptors & activates them
Excess neurotransmitter is taken
up by the pre-synaptic neurone
Enzymes are released to break down
the remaining neurotransmitter
Vesicles are replenished with new
& reused neurotransmitter
What Does It Look Like?
Let’s Synapse!
• Each person in your group has a label that
identifies which part of the process of synaptic
transmission you are.
• Your group must order themselves in such a
way that will demonstrate the process of
synaptic transmission.
Excitatory or Inhibitory
• Excitatory potentials: increases the chance of
the neuron firing.
• Inhibitory potentials: decreases the chance of
a neuron firing.
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.
http://www.youtube.com/watch?v=_chkzzvFvoQ
http://www.youtube.com/watch?v=90cj4NX87Yk&feature=related
Neurotransmitters
A chemical passed from one neuron to another which either excites or
inhibits the cell.
Excitatory
synapses –make
next nerve likely
to fire
Inhibitory
synapses make
next nerve less
likely to fire
6.3 Neurochemistry
The Endocrine System
https://www.youtube.com/watch?v=HXPCQBD_WGI
The Endocrine System
• The endocrine system is in charge of
body processes that happen slowly,
such as cell growth.
• Faster processes like breathing and
body movement are controlled by
the nervous system.
• However, even though the nervous
system and endocrine system are
separate systems, they often work
together to help the body function
properly.
These release
adrenalin
directly into
the
bloodstream
which
prepares the
body for fight
or flight by
constricting
blood vessels
in the
stomach.
This inhibits
digestion and
gives you that
sick feeling as
well as
increasing
your heart
rate
This controls
the release of
hormones
from all other
endocrine
glands
This facilitates
the release of
the female
hormones –
oestrogen and
progesterone
This facilitates the release of the
male hormones – testosterone
Summary questions
• Using an example, explain what is meant by
the fight or flight response
If you hear a noise that makes you jump, your
body immediately diverts blood away from
your stomach to your muscles in order for you
to stay and confront a potential attacker
(fight), or run away (flight)
Summary questions
• Give two actions of the sympathetic nervous
system and two actions of the
parasympathetic nervous system
• Sympathetic nervous system – dilates pupils, inhibits saliva
production, dilates bronchi, speeds up heart rate, inhibits
digestion, stimulates glucose production, inhibits urination
• Parasympathetic nervous system – constricts pupils,
stimulates saliva production, constricts bronchi, slows down
heart rate, stimulates digestion, stimulates bile production,
stimulates urination
Summary questions
• Billy is an A level student. He has been asked by
his teacher to give a short presentation to the
other psychology students in his class. Just before
his presentation, Billy feels his mouth go dry and
he starts to sweat. After the presentation has
ended, Billy feels his breathing slow down and he
begins to feel thirsty.
• Use your knowledge of the autonomic nervous
system to explain Billy’s behaviour before and
after the presentation.
Possible answer
Billy feels stressed about giving a presentation to the
class and this activates sympathetic responses in his
autonomic nervous system. Blood is diverted to the
muscles for energy and as a result, Billy sweats to allow
heat energy to be lost from the surface of the skin. It is
the body’s cooling mechanism. His salivary glands have
inhibited saliva production making his mouth go dry.
Once the presentation is over, Billy’s stress is no longer
present and his parasympathetic nervous system is now
acting to restore his bodily functions to a normal state;
this is why his breathing is slowing down. He feels thirsty
as his previously inhibited saliva production has dried his
mouth out and now he is aware of this and this needs
rectifying
The Endocrine System
Composed of a number of glands that release hormones.
Hormones travel through the bloodstream and affect different body organs.
Endocrine system provides an additional means of communication in the nervous
system.
The pituitary gland – ‘the Master Gland’ which controls other glands – it is located
deep in the middle of the brain in the hypothalamus.
The most important gland psychologically is the adrenal gland - adrenaline – the
stress hormone.
When the brain perceives an event as stressful the Brain stimulates the sympathetic
nervous system which instructs the adrenal gland to release the hormone
adrenaline.
6.4 Fight or Flight Response
Walter Cannon (1932) idea of flight or fight
response provides a relationship between
arousal and stress.
‘response to a stressor that results in a state of
physiological arousal so that the individual is
prepared to take flight or fight”
Fight or Flight
http://www.youtube.com/watch?v=J968Wco1u0s&feature=related
http://www.youtube.com/watch?v=V08dWz5XNBA&feature=related
http://www.youtube.com/watch?v=4g25d7_Afmc&feature=related
http://www.youtube.com/watch?v=ZEhPIxOxkuY&feature=related
Activity:
Draw two bodies on two separate pages.
Annotate
A) The ANS and Endocrine Response
B) The Sympathetic and Parasympathetic
Response.
Central Nervous System
The effects of stress: Fight or Flight
Central Nervous System
Stress and the nervous system
Cerebral Cortex – sends signals to
Hypothalamus – coordinates homeostasis and
stress response
Sends message down the ANS – sympathetic
nervous system
Discussion
Human stress mechanisms have not evolved to
cope with modern society. The mechanisms
are more damaging to health than helpful.
Many stress situations are not life threatening –
so why do we have a flight or fight response?
Plenary
•
•
•
•
•
•
•
Key Points
ANS – involuntary
Sympathetic – fight or flight
Parasympathetic – rest and digest
Endocrine system works in conjunction with
the sympathetic nervous system.
Quiz
• Write down five quiz questions and the
answers.
• Quiz your partner.
• Swap your questions and find a new partner.