Neurons and Membrane Potential Vocabulary Flashcards

Vocabulary practice cards covering fundamental neuroscience concepts including neuron anatomy, glial cell functions, resting potential mechanics, ionic gradients, and action potential propagation.

Sensory Neurons (Afferent Neurons)

Neurons of the peripheral nervous system (PNS) that carry sensory information ascending toward the central nervous system (CNS).

Motor Neurons (Efferent Neurons)

Neurons that convey motor commands away from the central nervous system (CNS) to target effectors, such as skeletal muscles.

Interneurons

Neurons located entirely within the central nervous system (CNS) that process signals and mediate communication between sensory and motor neurons.

Astrocytes

Star-shaped support cells in the central nervous system (CNS) that regulate and control the extracellular environment of neurons.

Microglia

Specialized glial cells that serve as the internal immune system of the central nervous system (CNS).

Ependymal Cells

Ciliated glial cells in the central nervous system (CNS) involved in the production and circulating movement of cerebrospinal fluid (CSF).

Oligodendrocytes

Glial cells responsible for forming the insulating myelin sheath around axons located within the central nervous system (CNS).

Schwann Cells

Glial cells in the peripheral nervous system (PNS) that form myelin sheaths around axons and form a proliferating cord to guide axon regeneration after injury.

Kinesin

A motor protein involved in anterograde axonal transport, moving secretory vesicles along microtubules away from the cell body toward the axon terminal.

Dynein

A motor protein involved in retrograde axonal transport, carrying recycled membrane vesicles along microtubules from the axon terminal back toward the cell body.

Plasticity

The capacity of the nervous system to remodel its neural pathways and connections in response to stimulation or injury, which is higher early in development.

Resting Membrane Potential

The steady potential difference across the plasma membrane of a resting excitable cell, typically around $-70\,\text{mV}$.

Electrochemical Gradient

The combined effect of concentration differences and electrical forces driving the movement of an ion across a membrane.

Nernst Equation

A mathematical formula ($E_{\text{ion}} = \frac{61}{Z}\log\left(\frac{C_{\text{out}}}{C_{\text{in}}}\right)$) used to calculate the equilibrium potential for a specific ion given its valence and concentrations.

Potassium Equilibrium Potential ($E_{\text{K}}$)

The theoretical membrane potential at which the electrical force pulling $K^+$ inward equals the concentration gradient pushing $K^+$ outward, calculated as $-90\,\text{mV}$.

Sodium Equilibrium Potential ($E_{\text{Na}}$)

The theoretical membrane potential at which electrical repelling forces balance the concentration gradient driving $Na^+$ into the cell, calculated as $+60\,\text{mV}$.

Depolarization

A change in membrane potential that shifts the electrical potential toward a less negative value or closer to $0\,\text{mV}$.

Repolarization

The phase during which the membrane potential returns back toward its original resting potential following depolarization.

Hyperpolarization

A membrane potential change that causes the interior of the cell to become more negative than its normal resting potential.

Overshoot

The period of an action potential during which the inside of the cell membrane becomes positively charged relative to the outside, rising above $0\,\text{mV}$.

Graded Potentials

Local changes in membrane potential that vary in magnitude according to stimulus strength and decay as they spread away from the stimulus site.

Action Potential

A rapid, large, all-or-none electrical reversal of membrane potential that propagates continuously down an excitable cell membrane.

Excitability

The physiological property possessed by neurons, muscle cells, and select other cell types to generate and propagate action potentials.

Absolute Refractory Period

The interval during an action potential when voltage-gated sodium channels are inactivated and no second action potential can be initiated regardless of stimulus strength.

Relative Refractory Period

The time interval following an action potential during which a second action potential can only be generated if triggered by a stronger-than-usual stimulus.

Saltatory Conduction

The mode of rapid nerve impulse propagation along a myelinated axon where action potentials jump from one Node of Ranvier to another.