Physiology of Excitable Cells: Axonal Conduction

A set of 40 fill-in-the-blank flashcards based on the lecture notes for the BS2015 course on Physiology of Excitable Cells, focusing on axonal conduction, electrical properties, and key concepts in neurophysiology.

Passive conduction is the __ flow of current along a neuron.

Passive flow of current along a neuron.

Action potentials are an process requiring ? to maintain concentration gradients for Na+ and K+.

Active process requiring energy.

The time constant is a measure of how quickly the __ potential changes in response to a stimulus.

Membrane potential changes.

The length constant measures how far an electrical potential (signal) will passively spread along a __ process.

Neuronal process.

In neurons, typical time constants are from ? to ? milliseconds.

20 to 50.

The formula for the time constant (τ) is τ = ?.

Rm x Cm.

The length constant (λ) depends on the resistance of the __, __, and _.

Membrane, cytoplasm (axial), extracellular fluid.

The resting membrane potential (Vm) is typically between and mV.

-70 and -80.

Increasing membrane permeability to a particular ion moves membrane potential towards _.

Equilibrium potential (EA).

Voltage-gated Na+ channels and K+ channels are crucial in determining the __ of the action potential.

Shape and properties.

The action potential is triggered when membrane potential reaches the __ threshold.

Action potential threshold.

Resting membrane potential is maintained primarily by the __ pump.

Na/K ATPase pump.

Increasing membrane resistance (Rm) and decreasing capacitance (Cm) leads to a _ conduction velocity.

Faster.

The __ period prevents back-propagation of an action potential.

Refractory period.

Demyelination in diseases such as __ alters conduction properties of neurons.

Multiple Sclerosis.

The movement of ions through channels is influenced by both and gradients.

Concentration, electrical.

An action potential is a ? and ? change of membrane potential.

Rapid, transient.

The velocity of an action potential is influenced by passive electrical properties of the __.

Membrane.

Passive conduction does not require energy; it takes place in the __ of action potentials.

Absence.

The __ potential is the membrane potential at which there is no net movement of ions across the membrane.

Equilibrium potential.

The formula for the length constant (λ) is __.

√(Rm/Ra).

DVm = DVmax x (1 - e^(-t/τ)) describes the __ relationship of membrane potential change.

Exponential.

Passive conduction is primarily governed by ? and ?.

Capacitance, resistance.

___ refers to the influence of passive electrical properties on the conduction of signals.

Myelination.

Increased membrane capacitance (Cm) requires __ current to change the membrane potential.

More.

The __ of Ranvier is crucial for saltatory conduction.

Node.

The size and shape of cells influence the __ spread of voltage signals.

Longitudinal.

Temporal accuracy is essential for proper information transfer in the __.

Nervous system.

The nodes of Ranvier have __ density of open Na+ channels.

High.

The importance of studying neural activity lies in understanding __ activities and pathologies.

Physiological.

The resting membrane potential moves closer to the equilibrium potential of the ion that has __ permeability.

Highest.

An increase in __ can enhance action potential conduction speed.

Myelination.

Neurons can use both active and passive methods to send __.

Signals.

The __ constant indicates how quickly a neuron can respond to a stimulus.

Time.

Measuring the resting potential at different concentrations helps in understanding the __ permeability.

Selective.

Neuronal conduction speed is influenced by __ of the surrounding environment.

Resistances.

In patients with multiple sclerosis, conduction velocity is __ due to demyelination.

Reduced.

When comparing intracellular and extracellular K+ concentrations, we see a __ gradient across the membrane.

Chemical.

The study of ion channels has provided insights into __ and their role in various physiological processes.

Potential therapeutic targets.

Variations in axonal myelination can lead to differences in __ conduction velocity.

Action potential.

The sodium-potassium pump helps maintain the __ across the neuronal membrane.

Membrane potential.

Resting potential can be altered by the opening of __ channels.

Ion.