50 Questions
Which connective tissue covering surrounds the entire muscle to hold it together and give it shape?
Epimysium
What is the basic functional unit of the myofibril?
Sarcomeres
Which plasma membrane surrounds an individual muscle fiber?
Sarcolemma
Which protein is responsible for positioning the myosin filament and maintaining equal spacing between the actin filaments in the sarcomere?
Titin
What is the role of titin in muscle contraction?
To provide increased force when muscles are stretched
What is the primary protein of the thick filament in the sarcomere?
Myosin
Which type of fibers showed a large increase after resistance exercise training in untrained young men and women?
Type IIa fibers
What type of fibers increased in prevalence after training for a marathon?
Type I fibers
What is the function of the plasmalemma in muscle fibers?
Maintain acid-base balance
Which protein is primarily responsible for the dark A-band in a sarcomere?
Myosin
What is the function of the M-line in a sarcomere?
To serve as the attachment site for the thick filaments
Which protein forms the backbone of the thin filament in a sarcomere?
Actin
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
Which type of muscle is found only in the heart and composes the vast majority of the heart's structure?
Cardiac muscle
Which type of muscle is under conscious control and is named because most attach to and move the skeleton?
Skeletal muscle
Which of the following statements accurately describes the neuromuscular junction?
It is the synapse between the α-motor neuron and a muscle fiber.
What is the term used to describe the process that triggers a muscle fiber to contract?
Excitation-contraction coupling
What is the role of calcium in the muscle fiber during the contraction process?
It binds to troponin and initiates the contraction process.
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
What happens when an α-motor neuron is activated?
All of the muscle fibers in its motor unit are stimulated to contract
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
What happens during muscle contraction?
The actin and myosin filaments slide with contraction
What is the H-zone?
The region that is no longer visible when the actin and myosin filaments overlap
What is excitation-contraction coupling?
The process of motor neuron activation leading to muscle contraction
What happens if the muscle cell is sufficiently depolarized?
An action potential is generated and muscle contraction occurs
Which type of muscle fibers showed a decrease in prevalence after resistance exercise training in untrained young men and women?
Hybrid fibers
Which type of muscle fibers showed an increase in prevalence after training for a marathon?
Type I fibers
What is the function of the sarcoplasmic reticulum (SR) in a muscle fiber?
Storage site for calcium
Which type of muscle is under conscious control and is named because most attach to and move the skeleton?
Skeletal muscle
What is the function of smooth muscle?
To move food through the digestive tract
What is the primary characteristic of cardiac muscle?
Composes the vast majority of the heart's structure
Which protein is primarily responsible for the dark A-band in a sarcomere?
Myosin
What is the function of the M-line in a sarcomere?
To stabilize the structure of the sarcomere
What is the role of titin in muscle contraction?
To serve as the attachment site for the thick filaments
Which protein is responsible for positioning the myosin filament and maintaining equal spacing between the actin filaments in the sarcomere?
Titin
What is the primary function of titin in muscle contraction?
All of the above
What is the role of calcium in the activation of titin during muscle contraction?
Calcium binds to titin, increasing its stiffness
Which of the following is the correct sequence of connective tissues surrounding a muscle fiber, from outermost to innermost?
Epimysium, perimysium, endomysium
What is the function of tendons in muscle fibers?
To transmit the force generated by muscle fibers to the bones
What is the role of hybrid muscle fibers in skeletal muscles?
To allow the muscle to achieve a greater range of contractile function
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
What is the primary protein of the thick filament in the sarcomere?
Myosin
What is the function of the plasmalemma in muscle fibers?
To transmit the action potential
Which of the following is responsible for the movement of the thin filaments towards the center of the sarcomere during muscle contraction?
Actin filaments
What happens when the H-zone overlaps and is no longer visible?
The sarcomere is in a contracted state
What is the sequence of events that starts with a motor nerve impulse and results in muscle contraction called?
Excitation-contraction coupling
What is the role of ACh in muscle contraction?
To open ion gates in the muscle cell membrane
What happens when an α-motor neuron is activated?
All muscle fibers in its motor unit are stimulated to contract
What is the primary protein of the thick filament in the sarcomere?
Myosin
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
Test your knowledge on the intricacies of neuromuscular junctions and excitation-contraction coupling in this quiz. Explore the communication between the nervous and muscular systems and understand the sequence of events that trigger muscle fiber contraction.
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