Nerve conduction, membrane potential, & action potentials

These flashcards cover key concepts and terms related to the nervous system, specifically focusing on nerve conduction, membrane potential, and action potentials.

What is the resting membrane potential (RMP) for a neuron?

The resting membrane potential for a neuron is measured to be -70 mV.

What creates the electrical gradient in neurons?

The Sodium-Potassium pump causes a charge separation, resulting in a cell being negative on the inside relative to the outside.

What are the three types of signals generated when the resting membrane potential changes?

The three types of signals are graded potentials and action potentials.

How do graded potentials differ from action potentials in terms of distance traveled?

Graded potentials decay quickly and only travel short distances, while action potentials do not decay and can travel long distances.

What happens during depolarization of a neuron?

Depolarization is the change from negative resting membrane potential (RMP) to positive RMP, typically from -70 mV to +30 mV.

What is hyperpolarization?

Hyperpolarization occurs when the membrane potential becomes even more negative than resting potential, such as -70 mV to -95 mV.

What is the role of the Na+/K+ pump in maintaining resting membrane potential?

The Na+/K+ pump maintains resting membrane potential by moving 3 Na+ ions out of the cell and 2 K+ ions into the cell.

What are EPSP and IPSP in relation to graded potentials?

EPSP (Excitatory Post Synaptic Potential) makes action potentials more likely, while IPSP (Inhibitory Post Synaptic Potential) makes them less likely.

What triggers an action potential in neurons?

An action potential is triggered when the threshold of -55 mV to -50 mV is reached, leading to depolarization.

What is the absolute refractory period?

The absolute refractory period is the time during which no action potential can be fired, as all Na+ gates are still open.

What characterizes saltatory conduction?

Saltatory conduction occurs in myelinated axons and is much faster due to insulation and the generation of action potentials at myelin sheath gaps.

What typically causes multiple sclerosis (MS)?

Multiple sclerosis is caused by the immune system attacking myelin sheaths in the CNS, leading to slowed impulse conduction.

What are the three groups of nerve fibers based on diameter and myelination?

Group A fibers are large and myelinated, Group B fibers are intermediate and lightly myelinated, and Group C fibers are small and unmyelinated.

How do local anesthetics affect action potentials?

Local anesthetics block voltage-gated Na+ channels, preventing action potentials from firing.

What is a characteristic of continuous conduction in nerve fibers?

Continuous conduction is slow and occurs in nonmyelinated axons.