Fundamentals of the Nervous System and Nervous Tissue

A set of vocabulary flashcards based on key concepts from the Nervous System and Nervous Tissue lecture notes.

Resting membrane potential

The membrane potential of a neuron not transmitting signals, approximately -70 mV.

Membrane polarization

When the inside of the cell is negatively charged relative to the outside.

Voltage

A measure of potential energy generated by separated charge, measured in volts (V) or millivolts (mV).

Current

Flow of electrical charge (ions) between two points.

Resistance

Hindrance to charge flow.

Ohm's law

A relationship between voltage, current, and resistance: I = V/R.

Chemically gated channels

Channels that open in response to the binding of a specific chemical, such as a neurotransmitter.

Voltage-gated channels

Channels that open and close in response to changes in membrane potential.

Mechanically gated channels

Channels that open and close in response to physical deformation of receptors.

Electrochemical gradient

The combined electrical and chemical gradients for ions.

Graded potentials

Localized changes in membrane potential due to stimuli, can lead to action potentials.

Depolarization

A decrease in membrane potential (making it less negative), increasing the likelihood of an action potential.

Hyperpolarization

An increase in membrane potential (making it more negative), decreasing the likelihood of an action potential.

Action potentials (AP)

Brief reversals of membrane potential used for long-distance signaling in neurons.

Threshold

The membrane potential at which an action potential is triggered, typically around -55 to -50 mV.

Absolute refractory period

Time during which no new action potential can be generated regardless of the strength of the stimulus.

Relative refractory period

Period following the absolute refractory period when a stronger than normal stimulus is needed to generate an action potential.

Continuous conduction

Slow conduction occurring in unmyelinated axons.

Saltatory conduction

Rapid conduction occurring in myelinated axons where action potentials jump from one node of Ranvier to another.

Multiple sclerosis (MS)

An autoimmune disease affecting the central nervous system, resulting in the destruction of myelin sheaths.

Na+/K+ pump

A pump that stabilizes the resting membrane potential by moving sodium out and potassium into the cell.