Neuromuscular Junctions and Excitation-Contraction Coupling Quiz

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Which connective tissue covering surrounds the entire muscle to hold it together and give it shape?

Perimysium

Endomysium

Sarcolemma

Epimysium (correct)

What is the basic functional unit of the myofibril?

Fascicles

Muscle fibers

Sarcomeres (correct)

Tendons

Which plasma membrane surrounds an individual muscle fiber?

Perimysium

Epimysium

Sarcolemma (correct)

Plasmalemma

Which protein is responsible for positioning the myosin filament and maintaining equal spacing between the actin filaments in the sarcomere?

Titin (B) Signup and view all the answers

What is the role of titin in muscle contraction?

To provide increased force when muscles are stretched (C) Signup and view all the answers

What is the primary protein of the thick filament in the sarcomere?

Myosin (D) Signup and view all the answers

Which type of fibers showed a large increase after resistance exercise training in untrained young men and women?

Type IIa fibers (D) Signup and view all the answers

What type of fibers increased in prevalence after training for a marathon?

Type I fibers (C) Signup and view all the answers

What is the function of the plasmalemma in muscle fibers?

Maintain acid-base balance (A) Signup and view all the answers

Which protein is primarily responsible for the dark A-band in a sarcomere?

Myosin (C) Signup and view all the answers

What is the function of the M-line in a sarcomere?

To serve as the attachment site for the thick filaments (B) Signup and view all the answers

Which protein forms the backbone of the thin filament in a sarcomere?

Actin (A) Signup and view all the answers

Which type of muscle is found in the walls of most blood vessels and allows for vessel constriction or dilation to regulate blood flow?

Smooth muscle (B) Signup and view all the answers

Which type of muscle is found only in the heart and composes the vast majority of the heart's structure?

Cardiac muscle (D) Signup and view all the answers

Which type of muscle is under conscious control and is named because most attach to and move the skeleton?

Skeletal muscle (C) Signup and view all the answers

Which of the following statements accurately describes the neuromuscular junction?

It is the synapse between the α-motor neuron and a muscle fiber. (C) Signup and view all the answers

What is the term used to describe the process that triggers a muscle fiber to contract?

Excitation-contraction coupling (C) Signup and view all the answers

What is the role of calcium in the muscle fiber during the contraction process?

It binds to troponin and initiates the contraction process. (D) Signup and view all the answers

Which of the following is the correct sequence of events that leads to muscle contraction?

Motor neuron activation, release of ACh, depolarization, action potential, muscle contraction (B) Signup and view all the answers

What happens when an α-motor neuron is activated?

All of the muscle fibers in its motor unit are stimulated to contract (C) Signup and view all the answers

What is the role of ACh in muscle contraction?

It opens up ion gates in the muscle cell membrane, allowing sodium to enter the muscle cell (A) Signup and view all the answers

What happens during muscle contraction?

The actin and myosin filaments slide with contraction (B) Signup and view all the answers

What is the H-zone?

The region that is no longer visible when the actin and myosin filaments overlap (D) Signup and view all the answers

What is excitation-contraction coupling?

The process of motor neuron activation leading to muscle contraction (D) Signup and view all the answers

What happens if the muscle cell is sufficiently depolarized?

An action potential is generated and muscle contraction occurs (A) Signup and view all the answers

Which type of muscle fibers showed a decrease in prevalence after resistance exercise training in untrained young men and women?

Hybrid fibers (C) Signup and view all the answers

Which type of muscle fibers showed an increase in prevalence after training for a marathon?

Type I fibers (C) Signup and view all the answers

What is the function of the sarcoplasmic reticulum (SR) in a muscle fiber?

Storage site for calcium (C) Signup and view all the answers

Which type of muscle is under conscious control and is named because most attach to and move the skeleton?

Skeletal muscle (C) Signup and view all the answers

What is the function of smooth muscle?

To move food through the digestive tract (C) Signup and view all the answers

What is the primary characteristic of cardiac muscle?

Composes the vast majority of the heart's structure (D) Signup and view all the answers

Which protein is primarily responsible for the dark A-band in a sarcomere?

Myosin (A) Signup and view all the answers

What is the function of the M-line in a sarcomere?

To stabilize the structure of the sarcomere (A) Signup and view all the answers

What is the role of titin in muscle contraction?

To serve as the attachment site for the thick filaments (D) Signup and view all the answers

Which protein is responsible for positioning the myosin filament and maintaining equal spacing between the actin filaments in the sarcomere?

Titin (A) Signup and view all the answers

What is the primary function of titin in muscle contraction?

All of the above (D) Signup and view all the answers

What is the role of calcium in the activation of titin during muscle contraction?

Calcium binds to titin, increasing its stiffness (A) Signup and view all the answers

Which of the following is the correct sequence of connective tissues surrounding a muscle fiber, from outermost to innermost?

Epimysium, perimysium, endomysium (A) Signup and view all the answers

What is the function of tendons in muscle fibers?

To transmit the force generated by muscle fibers to the bones (C) Signup and view all the answers

What is the role of hybrid muscle fibers in skeletal muscles?

To allow the muscle to achieve a greater range of contractile function (D) Signup and view all the answers

Which of the following is the correct sequence of events that leads to muscle contraction?

Action potential travels down the axon to the axon terminals (B) Signup and view all the answers

What is the primary protein of the thick filament in the sarcomere?

Myosin (B) Signup and view all the answers

What is the function of the plasmalemma in muscle fibers?

To transmit the action potential (D) Signup and view all the answers

Which of the following is responsible for the movement of the thin filaments towards the center of the sarcomere during muscle contraction?

Actin filaments (C) Signup and view all the answers

What happens when the H-zone overlaps and is no longer visible?

The sarcomere is in a contracted state (D) Signup and view all the answers

What is the sequence of events that starts with a motor nerve impulse and results in muscle contraction called?

Excitation-contraction coupling (C) Signup and view all the answers

What is the role of ACh in muscle contraction?

To open ion gates in the muscle cell membrane (A) Signup and view all the answers

What happens when an α-motor neuron is activated?

All muscle fibers in its motor unit are stimulated to contract (D) Signup and view all the answers

What is the primary protein of the thick filament in the sarcomere?

Myosin (D) Signup and view all the answers

What is the role of calcium in the muscle fiber during the contraction process?

To bind to troponin and expose the binding sites on actin (D) Signup and view all the answers

Neuromuscular Junctions and Excitation-Contraction Coupling Quiz

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Questions and Answers

Which connective tissue covering surrounds the entire muscle to hold it together and give it shape?

What is the basic functional unit of the myofibril?

Which plasma membrane surrounds an individual muscle fiber?

Which protein is responsible for positioning the myosin filament and maintaining equal spacing between the actin filaments in the sarcomere?

What is the role of titin in muscle contraction?

What is the primary protein of the thick filament in the sarcomere?

Which type of fibers showed a large increase after resistance exercise training in untrained young men and women?

What type of fibers increased in prevalence after training for a marathon?

What is the function of the plasmalemma in muscle fibers?

Which protein is primarily responsible for the dark A-band in a sarcomere?

What is the function of the M-line in a sarcomere?

Which protein forms the backbone of the thin filament in a sarcomere?

Which type of muscle is found in the walls of most blood vessels and allows for vessel constriction or dilation to regulate blood flow?

Which type of muscle is found only in the heart and composes the vast majority of the heart's structure?

Which type of muscle is under conscious control and is named because most attach to and move the skeleton?

Which of the following statements accurately describes the neuromuscular junction?

What is the term used to describe the process that triggers a muscle fiber to contract?

What is the role of calcium in the muscle fiber during the contraction process?

Which of the following is the correct sequence of events that leads to muscle contraction?

What happens when an α-motor neuron is activated?

What is the role of ACh in muscle contraction?

What happens during muscle contraction?

What is the H-zone?

What is excitation-contraction coupling?

What happens if the muscle cell is sufficiently depolarized?

Which type of muscle fibers showed a decrease in prevalence after resistance exercise training in untrained young men and women?

Which type of muscle fibers showed an increase in prevalence after training for a marathon?

What is the function of the sarcoplasmic reticulum (SR) in a muscle fiber?

Which type of muscle is under conscious control and is named because most attach to and move the skeleton?

What is the function of smooth muscle?

What is the primary characteristic of cardiac muscle?

Which protein is primarily responsible for the dark A-band in a sarcomere?

What is the function of the M-line in a sarcomere?

What is the role of titin in muscle contraction?

Which protein is responsible for positioning the myosin filament and maintaining equal spacing between the actin filaments in the sarcomere?

What is the primary function of titin in muscle contraction?

What is the role of calcium in the activation of titin during muscle contraction?

Which of the following is the correct sequence of connective tissues surrounding a muscle fiber, from outermost to innermost?

What is the function of tendons in muscle fibers?

What is the role of hybrid muscle fibers in skeletal muscles?

Which of the following is the correct sequence of events that leads to muscle contraction?

What is the primary protein of the thick filament in the sarcomere?

What is the function of the plasmalemma in muscle fibers?

Which of the following is responsible for the movement of the thin filaments towards the center of the sarcomere during muscle contraction?

What happens when the H-zone overlaps and is no longer visible?

What is the sequence of events that starts with a motor nerve impulse and results in muscle contraction called?

What is the role of ACh in muscle contraction?

What happens when an α-motor neuron is activated?

What is the primary protein of the thick filament in the sarcomere?

What is the role of calcium in the muscle fiber during the contraction process?

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