Exam 2 Topics for PSYC 255, Fall 2025

A collection of vocabulary flashcards covering key concepts related to the topics for Exam 2 in PSYC 255.

Blood Brain Barrier (BBB)

A selective barrier that prevents certain substances in the bloodstream from entering the brain, while allowing others to pass.

Circumventricular organ

Areas of the brain where the blood-brain barrier is weak, allowing for the detection of hormones and other substances in the bloodstream.

Heroin vs. Morphine Potency

Heroin is more potent than morphine due to its higher ability to cross the blood-brain barrier.

Korsakoff’s syndrome

A chronic neurocognitive disorder primarily caused by thiamine deficiency, often associated with alcohol misuse.

Cell membrane

A biological membrane that separates and protects the interior of all cells from the external environment.

Ion Channels

Proteins that allow ions to pass through the cell membrane, can be classified as passive, voltage-gated, or ligand-gated.

Sodium-Potassium Pump

A protein that actively transports sodium out of the neuron and potassium into the neuron, maintaining resting potential.

Hyperpolarizing stimulation

A type of stimulation that makes the inside of the neuron more negative compared to the outside.

Depolarizing stimulation

A type of stimulation that makes the inside of the neuron less negative or more positive.

Action Potential

A rapid, temporary change in a neuron's membrane potential that propagates along the axon.

Absolute refractory period

A time during which a neuron cannot fire another action potential, regardless of stimulation.

Relative refractory period

A time following an action potential during which a neuron can fire again only if the stimulus is strong enough.

Myelin sheath

A fatty layer that insulates the axon of neurons, speeding up the transmission of action potentials.

Nodes of Ranvier

Gaps in the myelin sheath that facilitate the rapid conduction of action potentials along myelinated axons.

Multiple Sclerosis

A disease where the immune system attacks the myelin sheath of neurons, leading to communication problems between the brain and the rest of the body.

Inhibitory Postsynaptic Potential (IPSP)

A hyperpolarizing change in the postsynaptic neuron, making it less likely to fire an action potential.

Excitatory Postsynaptic Potential (EPSP)

A depolarizing change in the postsynaptic neuron, making it more likely to fire an action potential.