Download nervous-system-structure-and-function

Biological level of analysis
2.1: Physiology and behaviour
The Nervous system:
structure and function
By Ms Lindstrom
How much does a brain weigh?
Answer
• An average brain weighs 1,3-1,4 kilos
One way to study biological
psychology:
• Physiology: how the nervous system and
hormones work, how the brain functions, how
changes in structure and/or function can
affect behaviour. For example, we could ask how
prescribed drugs to treat depression affect behaviour
through their interaction with the nervous system.
• Therefore, If we want to understand all
aspects of behaviour, perhaps we should start
with one of the smallest units, the basic
building block of the body, the cell.
The Neuron
• The neurons (nerve cells) are one of the
building blocks of behaviour.
• The Neurons send electrochemical messages
to the brain so that people can respond to
stimuli.
Central Nervous System
Neurons
• The human brain is made up of around 10 –
100 billion neurons. The total collection of
nerve cells in the body is called the nervous
system and the major part of the nervous
system, consisting of the brain and the spinal
cord, is called the central nervous system
(CNS).
• Neurons outside the CNS, which take
information between the CNS and various
regions of the body, are called peripheral
neurons.
The Nervous System
The nervous system is made up of the central nervous system, covering of the brain
and the spinal cord, and the peripheral nervous system. The latter is further divided
into the somatic division and the autonomic division. The somatic division controls
voluntary movements and the communication of information to and from the sense
organs. The autonomic division controls involuntary functions such as those of the
heart, blood vessels and lungs. The autonomic division is further divided into the
sympathetic and the parasympathetic divisions. The former prepares the body in
emergency situations and the latter helps the body return to its resting state.
The Spinal Reflex
Neurons handle information in
the body, taking messages
from one part of the body to
another.
Neurons
Outgoing information p. 39
A typical motor neuron see p. 39 in your book
nucleus: contains genetic information
cell body: houses the nucleus and other structures common to all living cells
axon: a thin cylinder of protoplasm which projects away from the cell body and carries signals
from the dendrites to other neurones
dendrites: branch out from the cell body, and receive signals from neighbouring neurones
myelin sheath: a white fatty substance, which insulates the axon and speeds up the rate of
transmission
Nodes of Ranvier: points along the axon which are not covered by the myelin sheath
presynaptic terminal: the small buttons at the end of the branches of the axon
Neurons
McGyver Excersise
• In groups of five
• Create a model of a “neuron” using whatever
material you can find
• You have 5 minutes!
Neurotransmission
• Is the method by which these messages are
sent by
With an electrical impulse down the axon of the
neuron, it releases neurotransmitters which
then cross the gap to another neuron. This
gap is called a synapse.
Neurotransmitters are the body’s natural
chemical messengers (of information)
Neurotransmission
• Underlies behaviour as mood, memory, sexual
arousal and mental illness.
• Drugs as alcohol, marihuana, Ecstasy,
Cocaine… affect our neurotransmissions in
different ways, producing therefore different
outcomes/experiences.
• Psychopharmalogical drugs work in the same
way, trying to affect our neurotransmissions to
either simulate or to block it, but with the
mission of improving the lives
Neurotransmitters
• Examples:
• Acetylcholine – muscle contraction, memory
• Dopamine – voluntary movement, learning,
feelings of pleasure
• Noradrenaline – arousal, alertness,
stimulating the sympathetic nervous system
• Serotonin – sleep, arousal levels, emotion
In total there are over fifty identified transmitter
substances
Neurotransmitters
• “brain's language and acts as the volume
buttons”
• When we feel, think, and remember the
neurotransmitters are involved.
• Depression, neuroses and psychoses can be
caused by problems with neurotransmitters.
Videos
NEURONS AND NEURO-TRANSMITTERS
http://www.youtube.com/watch?v=FR4S1BqdF
G4
Brain of a genius:
•http://dsc.discovery.com/videos/understanding
-the-brain-genius.html
•Teenage brain:
•http://dsc.discovery.com/videos/understanding
-the-brain-teenagers.html
Questions
• 1. What is a neuron?
• 2. Explain the meaning of the statement
`Neurons are the building blocks of the entire
nervous system'.
• 3. What is a neurotransmitter?
Brain
Group work: present in the following order and make a power
point presentation (and a poster) about your topic
•
2: General mapping of the brain:
include localization and function of the areas and layers. What happens if it becomes damaged? (give two
examples) How do we know about these areas today? Do not include Broca’s and Wernicke’s area!
•
2: McGuire: taxi drivers: mapping, description of the area, study (aim, procedure and findings)
•
2:Broca’s area and Wernice’s area: mapping, description of the area, history (why it is called Brocas’s area,
Wernice’s area, study + method)
•
2: split brain surgery: what is split brain surgery (Study by Sperry +method)?
•
•
Neurotransmitters:
2: Acetylcholine (Ahc): describe its use and function and what happens if one has too much or too
little of it (link it to a study) describe the study (aim, procedure and findings)
•
2:Dopamine: describe its use and function and what happens if one has too much or too little of it
(link it to a study and describe the study (aim, procedure and findings)
•
2: Serotonin: describe its use and function and what happens if one has too much or too little of it (link
it to a study) describe the study (aim, procedure and findings)
• Assessment details: see handout ”Rubric for the Brain Group Work”
• Find info in your textbook, revision guide (handouts) and on the internet