Physiology of Musculoskeletal System

Flashcards covering key concepts related to the physiology of the musculoskeletal system, focusing on excitable tissues, action potentials, and the role of ions in nerve and muscle function.

What are the excitable tissues that respond to stimuli?

Nerve and muscle tissues.

What occurs in a resting membrane potential (RMP)?

A potential difference created across the cell membrane by metabolic processes.

What is the typical RMP for nerves?

-70 mV.

Why is the interior of a cell negatively charged at rest?

Due to greater diffusion of K+ out of the cell than Na+ into the cell.

What is the primary function of the Sodium-Potassium Pump?

Maintain sodium and potassium concentration across the membrane.

What is the threshold potential for activating sodium channels?

About -50 to -55 mV.

What are the stages of action potential?

1. Slow depolarization, 2. Firing level, 3. Rapid complete depolarization, 4. Overshoot.

What is the 'All or Nothing' principle?

A neuron either fires at maximum intensity or not at all, depending on whether the stimulus reaches threshold.

What is hyperpolarization?

When the inside of the neuron becomes more negative than the resting potential.

What is the significance of myelin in nerve conduction?

Myelin sheath allows for faster signal transmission through saltatory conduction.

How does excitability change with increasing extracellular calcium concentration?

High calcium levels decrease excitability by stabilizing the membrane.

What are local potentials?

Graded potentials that produce response but do not reach action potential.

What defines the refractory period?

The time during which a nerve fiber cannot be excited again immediately after an action potential.

What type of conduction occurs in unmyelinated nerve fibers?

Continuous conduction.

What factors affect the strength of a stimulus?

Rate of application, strength, and duration.

How does a voltage-gated sodium channel function during action potential?

It opens to allow Na+ influx, leading to depolarization.

What is the function of the ryanodine receptor in muscle contraction?

Releases Ca++ from the sarcoplasmic reticulum to initiate muscle contraction.

What is depolarization in action potential?

A decrease in membrane potential, making the inside of the neuron more positive due to Na+ influx.

What triggers the release of neurotransmitters at the synaptic cleft?

The arrival of an action potential at the axon terminal, causing voltage-gated calcium channels to open.

What role does the refractory period play in nerve firing?

It ensures that action potentials only travel in one direction along the axon and limits the frequency of firing.

What happens during repolarization in an action potential?

Voltage-gated sodium channels close, and potassium channels open, allowing K+ to exit the cell, restoring negative membrane potential.

What is the role of the myelin sheath in nerve fibers?

It insulates the axon, increasing signal transmission speed through saltatory conduction, where action potentials jump between nodes of Ranvier.

What is the role of myelin in nerve conduction?

Myelin sheath allows for faster signal transmission through saltatory conduction.

What are local potentials?

Graded potentials that produce response but do not reach action potential.

What type of conduction occurs in unmyelinated nerve fibers?

Continuous conduction.

How does the voltage-gated sodium channel function during action potential?

It opens to allow Na+ influx, leading to depolarization.

What is the significance of the Sodium-Potassium Pump?

Maintain sodium and potassium concentration across the membrane.