everything psychological is simultaneously _________ every idea, mood, urge is a biological...
TRANSCRIPT
Everything psychological is simultaneously
_________ Every idea, mood, urge is a biological happening
Love, laugh, and cry with your body Many people talk separately about biological and
psychological influences on behavior “To think, feel, or act without a body would be like
running without legs”
Biological Bases of Behavior
Biological Psychologists: branch of
psychology concerned with the links between _________ & __________ Each system is composed of subsystems that
are in turn composed of even smaller subsystems
Biological Psychologists
Structure and CommunicationStructure and Communication
The basic building block of the nervous system -- a nerve _____
Neurons perform three basic tasks Receive Carry Pass on to the next
neuron
Neurons – What are they?
The brain is made up of approximately ________ neurons.100 billion
electrochemical electrochemical informationinformation
Sensory Neurons (a.k.a. Afferent Neurons) carry incoming information from the sense receptors to the CNS.
Motor Neurons (a.k.a. Efferent Neurons) carry outgoing information from the CNS to muscles and glands.
Interneurons connect the two neurons.
Kinds of Neurons
Sensory Neuron Interneuron Neuron
Motor Neuron
• Sensory neurons take info. from the senses to the brain.
• Interneurons take messages from sensory neurons to other parts of the brain or to motor neurons.
• Motor neurons take info. from the brain to the rest of the body.
Structure of a Neuron
Structure of a Neuron – Dendrites
Structure of a Neuron – Soma
Structure of a Neuron – Axon
Structure of a Neuron – Neural Impulse
Structure of a Neuron – Myelin Sheath
Structure of a Neuron – Terminals
Neurons come in a variety of shapes and sizes, but they all have the same basic structure
Neurons – magnified view
Neuron – another view
Neurons send messages to other neurons – this is
what keeps every part of our body in communication with every other part.
Neurons “fire” – send an impulse (message) down their length – or they don’t “fire”
Neurons – How do they work?
This “firing” of impulse messages is called the
action potential. Action potential: is a brief electrical charge
that travels down the axon of the neuron.
Action Potentialshttp://brainu.org/files/movies/action_potential_cartoon.swf
Resting Potential: when a neuron is
at rest and capable of generating an action potential There are fluids inside and outside of the
neuron, filled with electrically charged particles (ions) When the neuron is at rest, there is a negative
charge on the inside of the neuron compared to the outside.
What causes an impulse to fire or not fire?
Stimulation from inputs to dendrites causes
the cell membrane to open briefly Positively charged sodium ions flow in
through the cell membrane If resting potential rises above threshold,
an action potential starts to travel from the cell body down the axon Threshold - Each neuron receives excitatory
and inhibitory signals from many neurons. When the excitatory signals minus the inhibitory
signals exceed a minimum intensity (threshold) the neuron fires an action potential.
Action Potentials, cont.
Refractory period - The “recharging phase”
when a neuron, after firing, cannot generate another action potential
Action Potential, cont.
All-or-None Principle: if a
neuron fires it will always fire at the same intensity A strong stimulus can trigger more
neurons to fire, and to fire more often, but all action potentials are of the same strength and speed.
A neuron does NOT fire at 30%, 45% or 90% but at 100% each time it fires.
Neuron Communication
Just like a gun, there is no “part-way” firing
Action Potential
Instructor’s Notes
Copyright © Houghton Mifflin Company. All rights reserved.
PowerPoint® 2000 or better with Flash® plug-in required to view animations.
Right-click on animation for playback controls.
So what, exactly, are
neurotransmitters and what do they do?
Neurotransmitters: chemical
messenger that travels across the synapse from one neuron to the next
Can influence whether the second neuron will generate an action potential or not
Neurotransmitters
NeurotransmitterNeurotransmitter FunctionFunction ExamplesExamples
Acetylcholine (ACh)Acetylcholine (ACh)Released by motor neurons
controlling skeletal muscles. Enables muscle action, attention, arousal, and
memory
• With Alzheimer’s disease, ACh-producing neurons deteriorate.
• Some ACh receptors stimulated by nicotine.
Dopamine (DA)Dopamine (DA)
Influences voluntary movement, learning,
attention, and pleasurable emotions
• Excess dopamine receptor activity linked to schizophrenia.
• Decreased levels produce the decreased mobility and tremors of Parkinson’s disease.
Serotonin Serotonin
Affects mood, hunger, sleep, and arousal
• Undersupply linked to depression and obsessive-compulsive disorder.
• Prozac and some other antidepressant drugs raise serotonin levels.
Select Neurotransmitters
How Neurotransmitters Influence Us • Serotonin
pathways are involved with mood regulation.
• Dopamine pathways are involved with diseases such as:
• Schizophrenia (too much DA)
• Parkinson’s disease (not enough DA).
Select Neurotransmitters (cont.)
Neurotransmitter Function Examples
Norepinephrine (NE)Helps control alertness,
mood, and arousalUndersupply can depress mood.
GABA (gamma-aminobutyric acid)
A major inhibitory neurotransmitter
Undersupply linked to seizures, tremors, and
insomnia.
Endorphins Contribute to pain relief and perhaps to some pleasurable emotions
(“Runner’s High”)
Resemble opiate drugs in structure and effects
Glutamate A major excitatory
neurotransmitter; involved in memory
Oversupply can overstimulate brain,
producing migraines or seizures (which is why some people avoid MSG,
monosodium glutamate, in food)