Muscle Contraction and Function

Flashcards covering key concepts from muscle contraction and function.

What is a crossbridge in muscle physiology?

A structure that extends from myosin and interacts with actin during muscle contraction.

What is the role of myosin ATPase in muscle contraction?

It hydrolyzes ATP to provide energy for crossbridge movement.

What is a power stroke?

The action of the crossbridge pulling actin filaments during muscle contraction.

How does calcium influence muscle contraction?

Calcium binds to troponin, causing conformational changes that allow myosin to bind to actin.

What is the process called that links neuronal stimulation to muscle contraction?

Excitation-contraction coupling.

What are the two types of muscle contractions mentioned?

Isometric (no movement) and isotonic (changes in length).

What are slow twitch fibers primarily used for?

Sustained, endurance activities due to their ability to contract slowly and resist fatigue.

What is the significance of phosphocreatine in muscle activity?

It helps regenerate ATP quickly for muscle contractions.

What happens to calcium during muscle relaxation?

Calcium is actively transported back into the sarcoplasmic reticulum to allow muscle relaxation.

What defines a muscle twitch?

A single contraction followed by relaxation.

What is a crossbridge in muscle physiology?

A structure that extends from myosin and interacts with actin during muscle contraction.

What is the role of myosin ATPase in muscle contraction?

It hydrolyzes ATP to provide energy for crossbridge movement.

What is a power stroke?

The action of the crossbridge pulling actin filaments during muscle contraction.

How does calcium influence muscle contraction?

Calcium binds to troponin, causing conformational changes that allow myosin to bind to actin.

What is the process called that links neuronal stimulation to muscle contraction?

Excitation-contraction coupling.

What are the two types of muscle contractions mentioned?

Isometric (no movement) and isotonic (changes in length).

What are slow twitch fibers primarily used for?

Sustained, endurance activities due to their ability to contract slowly and resist fatigue.

What is the significance of phosphocreatine in muscle activity?

It helps regenerate ATP quickly for muscle contractions.

What happens to calcium during muscle relaxation?

Calcium is actively transported back into the sarcoplasmic reticulum to allow muscle relaxation.

What defines a muscle twitch?

A single contraction followed by relaxation.

What are fast twitch fibers primarily used for?

Short, rapid, and powerful movements as they contract quickly but fatigue easily.

Besides powering the power stroke, what other crucial role does ATP play in muscle contraction?

ATP binding to myosin causes the detachment of the myosin head from actin, allowing the crossbridge cycle to repeat.

What is the neuromuscular junction?

The specialized synapse between a motor neuron and a muscle fiber, where nerve impulses are transmitted to the muscle.

What is a crossbridge in muscle physiology?

A structure that extends from myosin and interacts with actin during muscle contraction.

What is the role of myosin ATPase in muscle contraction?

It hydrolyzes ATP to provide energy for crossbridge movement.

What is a power stroke?

The action of the crossbridge pulling actin filaments during muscle contraction.

How does calcium influence muscle contraction?

Calcium binds to troponin, causing conformational changes that allow myosin to bind to actin.

What is the process called that links neuronal stimulation to muscle contraction?

Excitation-contraction coupling.

What are the two types of muscle contractions mentioned?

Isometric (no movement) and isotonic (changes in length).

What are slow twitch fibers primarily used for?

Sustained, endurance activities due to their ability to contract slowly and resist fatigue.

What is the significance of phosphocreatine in muscle activity?

It helps regenerate ATP quickly for muscle contractions.

What happens to calcium during muscle relaxation?

Calcium is actively transported back into the sarcoplasmic reticulum to allow muscle relaxation.

What defines a muscle twitch?

A single contraction followed by relaxation.

What are fast twitch fibers primarily used for?

Short, rapid, and powerful movements as they contract quickly but fatigue easily.

Besides powering the power stroke, what other crucial role does ATP play in muscle contraction?

ATP binding to myosin causes the detachment of the myosin head from actin, allowing the crossbridge cycle to repeat.

What is the neuromuscular junction?

The specialized synapse between a motor neuron and a muscle fiber, where nerve impulses are transmitted to the muscle.

What neurotransmitter is released at the neuromuscular junction to initiate muscle contraction?

Acetylcholine (ACh).

What role does tropomyosin play in muscle contraction?

Tropomyosin blocks the myosin-binding sites on actin in a resting muscle, preventing contraction until calcium is present.

Where is calcium stored within muscle cells?

In the sarcoplasmic reticulum.

What is tetanus in muscle contraction?

A sustained muscle contraction without relaxation, resulting from a high frequency of stimulation.

What are the primary energy sources for ATP regeneration during prolonged muscle activity?

Aerobic respiration (oxidative phosphorylation) for endurance activities and glycolysis for shorter, more intense activities.

What is a crossbridge in muscle physiology?

A structure that extends from myosin and interacts with actin during muscle contraction.

What is the role of myosin ATPase in muscle contraction?

It hydrolyzes ATP to provide energy for crossbridge movement.

What is a power stroke?

The action of the crossbridge pulling actin filaments during muscle contraction.

How does calcium influence muscle contraction?

Calcium binds to troponin, causing conformational changes that allow myosin to bind to actin.

What is the process called that links neuronal stimulation to muscle contraction?

Excitation-contraction coupling.

What are the two types of muscle contractions mentioned?

Isometric (no movement) and isotonic (changes in length).

What are slow twitch fibers primarily used for?

Sustained, endurance activities due to their ability to contract slowly and resist fatigue.

What is the significance of phosphocreatine in muscle activity?

It helps regenerate ATP quickly for muscle contractions.

What happens to calcium during muscle relaxation?

Calcium is actively transported back into the sarcoplasmic reticulum to allow muscle relaxation.

What defines a muscle twitch?

A single contraction followed by relaxation.

What are fast twitch fibers primarily used for?

Short, rapid, and powerful movements as they contract quickly but fatigue easily.

Besides powering the power stroke, what other crucial role does ATP play in muscle contraction?

ATP binding to myosin causes the detachment of the myosin head from actin, allowing the crossbridge cycle to repeat.

What is the neuromuscular junction?

The specialized synapse between a motor neuron and a muscle fiber, where nerve impulses are transmitted to the muscle.

What neurotransmitter is released at the neuromuscular junction to initiate muscle contraction?

Acetylcholine (ACh).

What role does tropomyosin play in muscle contraction?

Tropomyosin blocks the myosin-binding sites on actin in a resting muscle, preventing contraction until calcium is present.

Where is calcium stored within muscle cells?

In the sarcoplasmic reticulum.

What is tetanus in muscle contraction?

A sustained muscle contraction without relaxation, resulting from a high frequency of stimulation.

What are the primary energy sources for ATP regeneration during prolonged muscle activity?

Aerobic respiration (oxidative phosphorylation) for endurance activities and glycolysis for shorter, more intense activities.

What is the basic contractile unit of a muscle fiber?

The sarcomere, extending from one Z-disc to the next, containing both actin and myosin filaments.

What is the fundamental principle describing how muscles contract at a molecular level?

The sliding filament theory, which states that muscle contraction occurs as the thin actin filaments slide past the thick myosin filaments, shortening the sarcomere.

What is the function of T-tubules in muscle contraction?

T-tubules (transverse tubules) are invaginations of the sarcolemma that allow action potentials to rapidly penetrate into the cell's interior, triggering calcium release from the sarcoplasmic reticulum.

What is a crossbridge in muscle physiology?

A structure that extends from myosin and interacts with actin during muscle contraction.

What is the role of myosin ATPase in muscle contraction?

It hydrolyzes ATP to provide energy for crossbridge movement.

What is a power stroke?

The action of the crossbridge pulling actin filaments during muscle contraction.

How does calcium influence muscle contraction?

Calcium binds to troponin, causing conformational changes that allow myosin to bind to actin.

What is the process called that links neuronal stimulation to muscle contraction?

Excitation-contraction coupling.

What are the two types of muscle contractions mentioned?

Isometric (no movement) and isotonic (changes in length).

What are slow twitch fibers primarily used for?

Sustained, endurance activities due to their ability to contract slowly and resist fatigue.

What is the significance of phosphocreatine in muscle activity?

It helps regenerate ATP quickly for muscle contractions.

What happens to calcium during muscle relaxation?

Calcium is actively transported back into the sarcoplasmic reticulum to allow muscle relaxation.

What defines a muscle twitch?

A single contraction followed by relaxation.

What are fast twitch fibers primarily used for?

Short, rapid, and powerful movements as they contract quickly but fatigue easily.

Besides powering the power stroke, what other crucial role does ATP play in muscle contraction?

ATP binding to myosin causes the detachment of the myosin head from actin, allowing the crossbridge cycle to repeat.

What is the neuromuscular junction?

The specialized synapse between a motor neuron and a muscle fiber, where nerve impulses are transmitted to the muscle.

What neurotransmitter is released at the neuromuscular junction to initiate muscle contraction?

Acetylcholine (ACh).

What role does tropomyosin play in muscle contraction?

Tropomyosin blocks the myosin-binding sites on actin in a resting muscle, preventing contraction until calcium is present.

Where is calcium stored within muscle cells?

In the sarcoplasmic reticulum.

What is tetanus in muscle contraction?

A sustained muscle contraction without relaxation, resulting from a high frequency of stimulation.

What are the primary energy sources for ATP regeneration during prolonged muscle activity?

Aerobic respiration (oxidative phosphorylation) for endurance activities and glycolysis for shorter, more intense activities.

What is the basic contractile unit of a muscle fiber?

The sarcomere, extending from one Z-disc to the next, containing both actin and myosin filaments.

What is the fundamental principle describing how muscles contract at a molecular level?

The sliding filament theory, which states that muscle contraction occurs as the thin actin filaments slide past the thick myosin filaments, shortening the sarcomere.

What is the function of T-tubules in muscle contraction?

T-tubules (transverse tubules) are invaginations of the sarcolemma that allow action potentials to rapidly penetrate into the cell's interior, triggering calcium release from the sarcoplasmic reticulum.

What is a motor unit?

A single motor neuron and all the muscle fibers it innervates.

What is muscle fatigue?

The decline in a muscle's ability to generate force even when it is still receiving neural stimulation.

What is the length-tension relationship in muscle contraction?

The relationship between the initial resting length of a muscle fiber and the amount of force (tension) it can generate upon contraction, with optimal force generated at an intermediate length.

What is summation in muscle contraction?

The increase in muscle tension or force caused by successive stimuli that occur before the muscle has completely relaxed from the previous twitch, leading to a stronger total contraction.

What is a crossbridge in muscle physiology?

A structure that extends from myosin and interacts with actin during muscle contraction.

What is the role of myosin ATPase in muscle contraction?

It hydrolyzes ATP to provide energy for crossbridge movement.

What is a power stroke?

The action of the crossbridge pulling actin filaments during muscle contraction.

How does calcium influence muscle contraction?

Calcium binds to troponin, causing conformational changes that allow myosin to bind to actin.

What is the process called that links neuronal stimulation to muscle contraction?

Excitation-contraction coupling.

What are the two types of muscle contractions mentioned?

Isometric (no movement) and isotonic (changes in length).

What are slow twitch fibers primarily used for?

Sustained, endurance activities due to their ability to contract slowly and resist fatigue.

What is the significance of phosphocreatine in muscle activity?

It helps regenerate ATP quickly for muscle contractions.

What happens to calcium during muscle relaxation?

Calcium is actively transported back into the sarcoplasmic reticulum to allow muscle relaxation.

What defines a muscle twitch?

A single contraction followed by relaxation.

What are fast twitch fibers primarily used for?

Short, rapid, and powerful movements as they contract quickly but fatigue easily.

Besides powering the power stroke, what other crucial role does ATP play in muscle contraction?

ATP binding to myosin causes the detachment of the myosin head from actin, allowing the crossbridge cycle to repeat.

What is the neuromuscular junction?

The specialized synapse between a motor neuron and a muscle fiber, where nerve impulses are transmitted to the muscle.