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PSY 345 Biological Psychology
Study Guide 04
Action Potential
Today’s guide explores cells. What they are and what their basic components are. Then, we’ll
talk about the specialized cells that make up the brain (i.e. neurons and glia). We’ll also talk
about the general environment the central nervous system inhabits.
READING: pps. 37-46
What does it mean to be positively or negatively charged, how can a protein have a charge, and
what are cations and anions?
What is an electrical gradient, how does the gradient lead to polarization and a resting potential,
and how does the membrane of the cell work to maintain this gradient?
How does one measure the resting potential and electrical activity inside neurons?
How does the flow of sodium, potassium, chloride, and calcium ions across the affect the
electrical potential of the cell. (Calcium ions are cations)
How does the sodium potassium pump work and what are the relative concentrations of sodium
and potassium ions in the intra- and extracellular space?
What are the electrical and concentration gradients and how do they want to move sodium,
potassium, chloride, and calcium ions? (There’s more calcium in the extracellular fluid)
What’s a voltage gated ion channel?
How do the electrical and concentration gradients in the ‘resting’ neuron coupled with the
voltage gated ion channels prepare the neuron to make respond strongly and rapidly?
What is the resting potential and what does it mean to depolarize or hyperpolarize a neuron?
What happens when a neuron is sufficiently depolarized and reaches its threshold potential (i.e.
between -40 & -55 mV)?
What happens at the peak of a neurons action potential and what do these changes lead to?
How do local anesthetics affect neural communications to block pain perception?
Explain the all-or-none law and why action potentials occur in an all or none fashion.
How can single neurons code information about the strength of a stimulus under the all-or-none
law?
What are the different types of refractory periods and why do they occur?
How is an action potential propagated?
What is a graded potential?
PSY 345 Biological Psychology
Study Guide 04
What is myelin and how does it increase the speed at which action potentials are propagated?