PSYB64 Physiological Psychology
Chapter 3 Vocabulary Terms
Action potential: The nerve impulse arising in an axon.
Neuron: A cell of the nervous system that is specialized for information processing and communication.
Glia: Cells in the nervous system that support the activities of neurons.
Organelle: A small structure within a cell that carries out a specific function.
Cell body/soma: The main mass of a neuron, containing the nucleus and many organelles.
Axon: The branch of a neuron usually responsible or carrying signals to other neurons.
Dendrite: The branch of a neuron that generally receives information from other neurons.
Intracellular fluid: The fluid inside a cell.
Extracellular fluid: The fluid surrounding a cell.
Permeability: A property of a substance that determines the extent to which other substances may pass
Ion channel: A protein structure embedded in a cell membrane that allows ions to pass without the use
of additional energy.
Ion pump: A protein structure embedded in a cell membrane that uses energy to move ions across the
Ion: An electrically charged particle in solution.
Voltage-dependent channel: An ion channel that opens or closes in response to the local electrical
Ligand-gated channel: An ion channel in the neural membrane that responds to chemical messengers.
Synapse: The junction between two neurons at which information is transferred from one to another.
Sodium-potassium pump: An ion pump that uses energy to transfer three sodium ions to the
extracellular fluid for every two potassium ions retrieved from the extracellular fluid.
Calcium pump: A protein structure embedded in the neural membrane that uses energy to move
calcium ions out of the cell.
Neurotransmitter A chemical messenger that transfers information across a synapse.
Cytoskeleton: A network of filaments that provides the internal structure of a neuron.
Microtubule: The largest fiber in the cell cytoskeleton, responsible for the transport of
neurotransmitters and other products to and from the cell body.
Anterograde transport: Movement of materials from the cell body of a neuron to the axon terminal
along the microtubules.
Retrograde transport: Movement of material from the axon terminal back to the cell body via the cell’s
system of microtubules.
Neurofilaments: A neural fiber found in the cell cytoskeleton that is responsible for structural support.
Microfilament: The smallest fiber found in the cell cytoskeleton that may participate in the changing of
the length and shape of axons and dendrites.
Nucleus: The substructure within a cell body that contains the cell’s DNA.
Nucleolus: A substructure within a cell nucleus where ribosomes are produced.
Ribosome: An organelle in the cell body involved with protein synthesis.
Endoplasmic reticulum: An organelle in the cell body that participates in protein synthesis.
Golgi apparatus: An organelle in the cell body that packages proteins in vesicles.
Mitochondria: Organelles that provide energy to the cell by transforming pyruvic acid and oxygen into
molecules of adenosine triphosphate (ATP).
Synaptic gap: The tiny fluid filled space between neurons forming a synapse.
Dendritic spine: A knob on the dendrite that provides additional membrane area for the formation of
synapses with other neurons.
Axon hillock: The cone-shaped segment of axon located at the junction of the axon and cell body that is
specialized for the generation of action potentials. Myelin: The fatty insulating material covering some axons that boosts the speed and efficiency of
Local circuit neuron: A neuron that communicates with neurons in its immediate vicinity.
Projection neuron: A neuron with a very long axon that communicates with neurons in distant areas of
the nervous system.
Collateral: One of the branches near the end of the axon closest to its targets.
Axon terminal: The swelling at the tip of an axon collateral specialized for the release of
Synaptic vesicle: A small structure in the axon terminal that contains neurotransmitters.
Node of Ranvier: The uncovered section of axon membrane between two adjacent segments of myelin.
Unipolar neuron: A neuron with one branch that extends a short distance from the cell body then splits
into two branches.
Bipolar neuron: A neuron with two branches, one axon and one dendrite.
Multipolar neuron: A neuron that has multiple branches, usually one axon and numerous dendrites.
Sensory neuron: A specialized neuron that translates incoming sensory information into electrical
Motor neuron: A specialized neuron that communicates with muscles and glands.
Interneuron: A neuron that serves as a bridge between sensory and motor neurons.
Macroglia: Large glial cells, including astrocytes, oligodendrocytes, and Schwann cells.
Microglia: Tiny, mobile glial cells that migrate to areas of damage and digest debris.