Nervous System Flashcards

Vocabulary flashcards for key terms related to the nervous system, electrical properties, and action potential.

Neuron

The primary cell type found in the CNS, capable of propagating electrical signals.

Neuroglia (Glial Cells)

Cells that provide critical support for neurons in the CNS and nerve cells in the PNS.

Astrocytes

Glial cells in the CNS that regulate blood flow, filter toxins, and assist in neurotransmitter reuptake (Glutamate).

Microglia

Immune cells of the CNS, responsible for mounting immune responses, mediating inflammation, and acting as phagocytes.

Ependymal Cells

Ciliated glial cells found in the ventricles of the brain, circulating cerebrospinal fluid (CSF), filtering toxins, and maintaining homeostasis.

Oligodendrocytes

Glial cells in the CNS responsible for myelination by wrapping axons with myelin sheaths.

Schwann Cells

Cells in the PNS responsible for myelination of nerve cells in the periphery.

Satellite Cells

Cells in the PNS that regulate the extracellular matrix surrounding peripheral nerve cells and provide a physical cushion.

Ion

An electrically-charged atom formed when an atom loses or gains an electron.

Cations

Positively-charged ions (e.g., Na+, K+, Ca2+).

Anions

Negatively-charged ions (e.g., Cl-).

Ion Channels

Specialized integral membrane proteins that allow specific ions to move into or out of the cell.

Membrane Potential

The charge difference across a cell’s membrane.

Chemical (Concentration) Gradient

The difference in concentration of an ion on either side of the membrane.

Equilibrium Potential

The membrane potential at which a single ion is at equilibrium.

Resting Potential

The stable membrane potential of a neuron when it is not firing an action potential (typically around -70 mV).

Action Potential

A unidirectional communication mechanism that allows neurons to send electrical signals.

Depolarization

The first phase of the action potential, when voltage-gated Sodium (Na+) channels open and Na+ flows into the cell.

Repolarization

The second phase of the action potential, when Sodium (Na+) channels close and Potassium (K+) ions flow out of the cell.

Hyperpolarization

A brief period in the action potential when more Potassium (K+) ions leave the cell, and voltage-gated channels slowly close.

Sodium-Potassium Pump

A protein pump that restores the resting potential by forcing three Sodium (Na+) ions out and pushing two Potassium (K+) ions into the cell.

Saltatory Conduction

The faster propagation of an action potential along a myelinated axon, where ion channels are only present at the Nodes of Ranvier.