Transcript The neuron - Ms Lindstrom`s Blog

Biological level of analysis
Nervous system:
structure and function
By Ms Lindstrom
How much does a brain weigh?
Answer
• An avarage 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
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 to and fro between the CNS and
various regions of the body, are called
peripheral neurons.
Nervous system
The nervous system is made up of the central nervous system, comprising 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
A typical motor neuron
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
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)
Outgoing 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:
• Acetlcholine – 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, feel 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=DF04XPBj5u
c&feature=related
Brain of a genius:
• http://dsc.discovery.com/videos/understandin
g-the-brain-genius.html
• Teenage brain:
• http://dsc.discovery.com/videos/understandin
g-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
•
3 persons mapping the brain:
include localization and function of the areas and layers. What happens if it becomes damaged? The history of the area. How do
we know about these areas today (link it to studies)? Do not include Broca’s and Wernickes area!
•
•
•
2:Brocas area: mapping, description of the area, history (why it is called Brocas’s area, study + method)
2: Wernicke’s area mapping, description of the area, history (why it is called Wernicke’s area, study + method)
2: Split brain surgery: what is split brain surgery (method)? Why is it used? Examples of studies and findings, history
•
•
Neurotransmitters:
2: serotonin: describe its use and function and what happens if one has too much or too little of it (link
it to a psychological illness that you find)
•
2: noradrenaline: describe its use and function and what happens if one has too much or too little of
it (link it to a psychological illness that you find)
•
2:Dopamine: describe its use and function and what happens if one has too much or too little of it
(link it to a psychological illness that you find)
• Assessment details: see handout ”Rubric for the Brain Group Work”