Download Brain and Behaviour

BRAIN AND BEHAVIOUR
Chapter
Over view
Notes
BRAIN AND BEHAVIOUR
1 st: Franz Gall “phrenology” the idea that
certain areas of the brain control certain
functions and behaviours.
Biological Psychologists: study the links
between biology and psychology and in doing
so are learning about depression, sleep,
dreams and schizophrenia.
THE NERVOUS SYSTEM
An electrochemical communication
system that enables you to think, feel
and act.
It is composed of nerve cells called
NEURONS
The Nervous System of animals and
humans are very similar and operate
similarly.
HOW DOES INFORMATION TRAVEL IN THE
NERVOUS SYSTEM?
 3 different types of nerve cells called Neurons:
 Sensory neuron (send information from sensory organs and
tissue to the brain and spinal cord)
 Interneuron (processes information in the brain and spinal
cord)
 Motor neuron (receives instructions from the brain and spinal
cord)
 The simplest neural response – The REFLEX – touch
a hot stove (pain reflex)
GENERATING A NEURAL IMPULSE
 Myelin Sheath – insulates to help speed
 Axon – passes information to other neurons
 Dendrites – receive information from other neurons
 For a neural impulse to “FIRE” the combined impulses that
reach the dendrite must reach a certain level of intensity or
THRESHOLD – this is an all of nothing response to neurons
either reaching the threshold or they don’t .
 If the Threshold is reached then the neuron transmits an
electrical impulse down the axon and this impulse that runs
down the axon is called the ACTION POTENTIAL .
 Stronger stimuli does not cause a stronger impulse to fire,
but, it can cause more neurons to fire and to fire more often.
HOW DO NERVE CELLS COMMUNICATE?
 The axon terminal of one neuron is separated from the
receiving neuron by a tiny gap known as the SYNAPSE or
SYNAPTIC GAP.
 To communicate with one another the neuron releases
chemicals called NEUROTRANSMITTERS into the synaptic gap .
 The neurotransmitters cross the synaptic gap and bind the
receptor sites on the receiving neuron – like a key fitting into
a lock .
 When these neurotransmitters bind to the receptor sites they
either EXCITE or INHIBIT the receptor neurons readiness to
fire.
 If a neuron receives more excitatory messages, it will fire.
 If a neuron receives more inhibitory messages it will not fire .
HOW DO NEUROTRANSMITTERS INFLUENCE US?
One of the best understood
neurotransmitters = acetylcholine
(messenger at every junction between a
motor neuron and a muscle neuron)
The Endorphins – neurotransmitters that
are similar to the drug morphine (which
elevates mood and eases pain). They are
natural opiates which are released in
response to pain and vigorous exercise.
DIVISIONS OF THE NERVOUS SYSTEM
 Central Nervous System: includes all neurons in the
brain and spinal cord.
 Peripheral Nervous System: links the CNS with the
body’s sense receptors, muscles and glands .
 Somatic Nervous System: transmits sensory input
from the outside world and directs motor input – the
voluntary movement of our skeletal muscles .
DIVISIONS OF THE NERVOUS SYSTEM
 Autonomic Nervous System: influences the glands
and muscles of our internal organs. It can be
consciously overridden but usually tends on its own
influence.
 Sympathetic Nervous System: fight or flight response
which accelerates heartbeat, slows digestion .
 Parasympathetic Nervous System: this calms you
down so the opposite of sympathetic nervous system .