Biological Psychology: Neurons and Behavior

Flashcards covering the cellular structure of the nervous system, the mechanics of action potentials, synaptic communication, and major neurotransmitters based on the lecture transcript.

Neuron

A separate cell that makes up the brain and human nervous system, of which there are approximately $12-15$ billion in the cerebral cortex and $70$ billion in the cerebellum.

Glia

Cells that are smaller but more numerous than neurons; they support neurons by insulating them, synchronizing activity, and removing waste products.

Cell body

The part of a neuron that contains the nucleus of the cell.

Dendrites

Widely branching structures, named after the Greek word for "tree," that receive input from other neurons.

Axon

A single, long, thin, straight fiber with branches near its tip that transmits information to other cells.

Myelin

An insulating sheath that covers some vertebrate axons and speeds up the transmission of impulses.

Action potential

An excitation that travels along an axon at a constant strength, regardless of the distance traveled.

All-or-none law

The principle stating that an axon cannot vary the strength or velocity of its action potentials; it is essentially an on-off message.

Resting potential

The electrical polarization across the membrane of an axon when it is not stimulated, typically measuring about $-70$ millivolts internally.

Sodium-potassium pump

A mechanism that pushes sodium ions out of the axon while pulling potassium ions in to maintain the resting potential.

Threshold

The specific level of excitation (typically about $-55$ millivolts) required to open the axon's gates and start an action potential.

Synapse

The specialized junction between one neuron and another where a chemical is released to either excite or inhibit the next cell.

Terminal bouton

Also known as a presynaptic ending, this is a bulge at the end of an axon branch that releases neurotransmitters.

Neurotransmitter

A chemical that activates receptors on other neurons; a given neuron usually releases only one or a few of the dozens of types available.

Postsynaptic neuron

The neuron on the receiving end of a synapse.

Reuptake

The process by which a neurotransmitter is reabsorbed by the axon that released it to end the message.

Otto Loewi

The researcher who conducted an experiment in 1920 with frog hearts to demonstrate that neurons communicate by releasing chemicals.

Glutamate

The brain's main excitatory neurotransmitter, essential for learning; excessive release during strokes can kill neurons.

GABA (gamma-amino-butyric acid)

The main inhibitory neurotransmitter in the brain; its activity is increased by anti-anxiety and anti-epileptic drugs.

Dopamine

A neurotransmitter with pathways important for movement and memory; its decay is associated with Parkinson's disease.

Serotonin

A neurotransmitter that modifies many types of motivated and emotional behavior; most antidepressants prolong its activity.

Endorphins

Neurotransmitters that decrease pain and increase pleasure; they are stimulated by morphine and heroin.

Parkinson's disease

A condition characterized by difficulty initiating movement and tremors, caused by the gradual decay of axons that release dopamine.

L-dopa

A drug that can cross from the blood into the brain to be converted into dopamine, used as a treatment for Parkinson's disease.