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Chapter 2

PSY 101 Chapter Notes - Chapter 2: Positron Emission Tomography, Resting Potential, Lesion


Department
Psychology
Course Code
PSY 101
Professor
Kim Plyler
Chapter
2

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Psych Notes – 9/8/14
The Biological Perspective
Biopsychological systems – Everything psychological is simultaneously biological
oThese things occur in a social context
oThese systems interact
Biological Psychology/Behavioral Neuroscience
Branch of psychology concerned with the links between biology and behavior
Cells of the Nervous System
Neurons: special cells that are responsible for communication between cells
Glia: Provide functional/structural support to neurons (migration in development, deliver
nutrients, waste removal, myelin sheath)
Parts of a Neuron
Cell Body (Soma) – the cell’s life support
center
Dendrites – receive messages from other cells
Axon – passes messages away from cell body
to neurons, muscles, or glands
Terminal branches – release information to
other cells
Neural impulse – electrical signal traveling
down the axon
Myelin sheath – covers the axon of some
neurons and helps speed neural impulses
Oligodendrocyte : glial cell that connects to myelin sheath which connects to the axon
Types of Neurons
Sensory neurons – neurons that carry information from the sensory receptors to the central
nervous system
Motor neurons – carry outgoing information from the central nervous system to the muscles
and the glands
Interneurons – neural connectors that link the sensory and motor neurons
oReflex arc – i.e. detecting a hot object
Neural Communication
Components:
oNeural impulse: message within a neuron
Action potential – Electrical signal that moves from the axon hillock, down the axon,
and into the terminal
When no message is received – the state of the neuron is at resting potential, the
resting charge of the neuron
Maintained by ions (inside neuron = negative, outside = positive)
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oMajor players:
Inside the Cell:
Potassium – (K+) more inside the cell
Proteins – (A-) more inside the cell
Outside the Cell:
Sodium – (Na+) more outside the cell
Chloride – (Cl-) more outside the cell
Calcium – (Ca++) more outside the cell
o2 forces act on major players
Chemical gradient (diffusion) – ions move from high concen. to low
Electrical gradient (electrostatic pressure) – ions move toward opposite charge
oSodium-Potassium transporter – keeps too much sodium from entering the cell and
changing the voltage
oAction potential: brief electrical impulse the provides the basis for conduction of
information along an axon to its terminal
Change of intracellular potential from -70mV to +40mV (depolarization)
Triggered when Na+ ions move into the cell
An electrical impulse that surges along an axon caused by an influx of positive ions in
the neuron
There is a threshold that has to be met before an action potential can occur
All or none: neurons either fire or they don’t – have to reach threshold
Neural Connections
Synapse – Junctions between the axon tip of the sending neuron and the dendrite or cell
body of the receiving neuron
Tiny gap at this junction is called the synaptic gap or cleft
Neural Communication
1. The action potential activates vesicles at the end of the
axon
2. Vesicles release neurotransmitters across the synapse
3. Neurotransmitters cross the synapse and bind to
receptors on the dendrites of the next neurons
4. Channels on the post-synaptic neuron open and allow the
action potential to continue
Terminating the message – don’t want NT staying in
the synapse long term
Reuptake – NT gets brought back into the terminal
Neurons must be turned on and off:
oExcitatory Neurotransmitter – NT that causes the receiving cell to fire
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