Anatomy Chapter 8: Muscular System Quiz

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Questions and Answers

What are the three types of muscular tissue?

Skeletal muscle tissue, Cardiac muscle tissue, Smooth muscle tissue

What are the features of Skeletal muscle tissue?

Attached to bones, striated, voluntary

What are the features of Cardiac muscle tissue?

Forms most of the wall of the heart, striated, involuntary

What are the features of Smooth muscle tissue?

Located in viscera, nonstriated, involuntary Signup and view all the answers

What are the 5 key functions of muscular tissue?

Produce body movements, stabilize body positions, regulating organ volume, moving substances within the body, producing heat Signup and view all the answers

What are the connective tissue coverings associated with muscular tissue?

Epimysium, perimysium, endomysium Signup and view all the answers

What are tendons?

Extensions of connective tissue beyond muscle fibers that attach muscle to bone Signup and view all the answers

What provides nutrients and oxygen to skeletal muscles for contraction?

Nerves and blood vessels Signup and view all the answers

Skeletal muscle consists of muscle fibers covered by a ______.

sarcolemma Signup and view all the answers

What do skeletal muscle fibers contain?

Sarcoplasm, multiple nuclei, mitochondria, myoglobin, and sarcoplasmic reticulum Signup and view all the answers

What is a sarcomere?

Arranged functional units of myofibrils containing thin and thick filaments Signup and view all the answers

Thick filaments are composed of _. Thin filaments are composed of .

Myosin; actin, tropomyosin, troponin Signup and view all the answers

Muscle contraction occurs when:

Myosin heads attach and walk along the thin filaments, pulling them toward the center Signup and view all the answers

What is the neuromuscular junction?

The synapse between motor neuron and skeletal muscle fiber Signup and view all the answers

What is a motor unit?

A motor neuron and all of the muscle fibers it stimulates Signup and view all the answers

What is the sliding filament mechanism?

The sliding of filaments and shortening of sarcomeres that cause shortening of muscle fibers Signup and view all the answers

What turns off the contraction cycle?

A decrease in level of Ca2+ in the sarcoplasm Signup and view all the answers

Describe the contraction cycle.

<ol> <li>Myosin ATPase splits ATP and becomes energized 2) Myosin head attaches to actin, forming a cross bridge 3) Cross bridge generates force as it moves to center 4) Binding of ATP to myosin detaches myosin from actin 5) Myosin head splits from ATP and returns to position</li> </ol> Signup and view all the answers

How is muscle tone produced?

Continual involuntary activation of a small number of motor units Signup and view all the answers

What are the three sources of ATP production in muscle fibers?

Creatine phosphate, anaerobic cellular respiration, and aerobic cellular respiration Signup and view all the answers

Creatine phosphate and ATP provide enough energy for muscles to contract maximally for ____________ seconds.

15 Signup and view all the answers

Anaerobic cellular respiration provides enough ATP for _________ seconds of maximal muscle activity.

30-40 Signup and view all the answers

Muscular activity that lasts longer than 1 minute depends on:

Aerobic cellular respiration Signup and view all the answers

What is muscle fatigue?

Inability of a muscle to contract forcefully after prolonged activity Signup and view all the answers

What is recovery oxygen uptake?

Elevated oxygen use after exercise Signup and view all the answers

What is a twitch contraction?

A brief contraction of muscle fibers in a motor unit in response to a single action potential Signup and view all the answers

What is myogram?

A record of a contraction (consists of latent period, contraction period, relaxation period) Signup and view all the answers

What is wave summation?

Increased strength of a contraction that occurs when a second stimulus arrives before the muscle has completely relaxed Signup and view all the answers

What is unfused (incomplete) tetanus?

A sustained muscle contraction with partial relaxation between stimuli Signup and view all the answers

What is fused (complete) tetanus?

A sustained muscle contraction without partial relaxation between stimuli Signup and view all the answers

What is motor unit recruitment?

Process of increasing the number of active motor units Signup and view all the answers

On the basis of structure and function, what are the three classifications of skeletal muscle fibers?

Slow oxidative fibers (SO fibers), fast oxidative-glycolytic fibers (FOG fibers), fast glycolytic fibers (FG fibers) Signup and view all the answers

What order are the motor units in a muscle recruited?

1 - SO fibers, 2 - FOG fibers, 3 - FG fibers Signup and view all the answers

Endurance-type (aerobic) exercises cause:

A gradual transformation of FG fibers into FOG fibers Signup and view all the answers

Exercises that require great strength for short periods of time produce:

An increase in the size and strength of FG fibers Signup and view all the answers

How do skeletal muscles produce movement?

By pulling on tendons attached to bones Signup and view all the answers

What is the origin?

Attachment to the stationary bone Signup and view all the answers

What is the insertion?

Attachment to the movable bone Signup and view all the answers

What does the prime mover (agonist) produce?

Desired action Signup and view all the answers

What does the antagonist produce?

Opposite action of the agonist Signup and view all the answers

What does the synergist do?

Assists the prime mover by helping to reduce unnecessary movement Signup and view all the answers

What does the fixator do?

Stabilizes the origin of the prime mover so it can act more efficiently Signup and view all the answers

Principle skeletal muscles of the body are grouped according to:

Region Signup and view all the answers

The names of most skeletal muscles indicate:

Specific characteristics Signup and view all the answers

What are the major descriptive categories of skeletal muscles?

Direction of fibers, location, size, number of origins, shape, origin and insertion, and action Signup and view all the answers

When older persons start losing skeletal muscle, what is it replaced by?

Fibrous connective tissue and fat Signup and view all the answers

Aging also results in a _ in muscle strength, muscle reflexes, and __ of flexibility.

Decrease; slower; loss Signup and view all the answers

Study Notes

Types of Muscular Tissue

Three types of muscular tissue: skeletal, cardiac, and smooth.
Skeletal muscle: attached to bones, striated, and under voluntary control.
Cardiac muscle: found in heart walls, striated, and involuntary.
Smooth muscle: located in viscera, non-striated, and involuntary.

Functions of Muscular Tissue

Produces body movements and stabilizes body positions.
Regulates organ volume and facilitates movement of substances within the body.
Generates heat as a byproduct of muscle activity.

Connective Tissue in Muscles

Epimysium: covers the entire muscle.
Perimysium: encases fascicles, or bundles of muscle fibers.
Endomysium: surrounds individual muscle fibers.

Muscle Attachments and Energy Supply

Tendons serve as extensions of connective tissue, attaching muscle to bone.
Nerves and blood vessels deliver nutrients and oxygen necessary for muscle contraction.

Muscle Fiber Structure

Each skeletal muscle fiber is encased in a sarcolemma.
Muscle fibers contain sarcoplasm, multiple nuclei, mitochondria, myoglobin, and sarcoplasmic reticulum.

Sarcomeres and Filament Composition

Sarcomeres are the functional units of myofibrils, composed of thick (myosin) and thin (actin, tropomyosin, troponin) filaments.

Muscle Contraction Mechanism

Muscle contraction occurs when myosin heads walk along thin filaments, pulling them toward the center.
The neuromuscular junction is the synapse between a motor neuron and a muscle fiber.
A motor unit consists of a motor neuron and the muscle fibers it stimulates.

Mechanisms and Types of Contraction

The sliding filament mechanism describes how filaments slide past each other to shorten muscle fibers.
Muscle contraction is controlled by calcium ions; a decrease in Ca2+ stops the contraction cycle.
Muscle tone results from the continuous involuntary activation of some motor units.

ATP Production Sources

Muscle fibers generate ATP through creatine phosphate, anaerobic, and aerobic respiration.
Creatine phosphate and ATP support maximal contraction for about 15 seconds.
Anaerobic respiration provides ATP for 30-40 seconds of intense activity.
Sustained activity beyond one minute relies on aerobic respiration.

Muscle Fatigue and Recovery

Muscle fatigue refers to the inability to contract forcefully after prolonged activity.
Recovery oxygen uptake involves increased oxygen consumption following exercise.

Muscle Contraction Patterns

Twitch contraction results from a single action potential.
Myograms record muscle contractions, showing the latent, contraction, and relaxation periods.
Wave summation increases contraction strength with successive stimuli.
Unfused tetanus exhibits partial relaxation, while fused tetanus maintains a strong, sustained contraction.

Skeletal Muscle Fiber Classification

Skeletal muscle fibers are classified into slow oxidative (SO), fast oxidative-glycolytic (FOG), and fast glycolytic (FG) fibers.
Recruitment order of fibers: SO, then FOG, then FG fibers.
Aerobic exercises can transform FG fibers into FOG fibers.
Strength training enhances FG fiber size and strength.

Muscle Movement Principles

Skeletal muscles move by pulling on tendons attached to bones.
Muscles have an origin (stationary attachment) and an insertion (movable attachment).
Prime movers (agonists) perform the primary action; antagonists provide opposing actions.
Synergists assist prime movers, and fixators stabilize the origin for efficient action.

Muscle Aging and Development

Major skeletal muscles are categorized based on region and characteristics.
Skeletal muscle names often reflect their features.
Muscle loss occurs around age 30, typically replaced by fibrous connective tissue and fat.
Aging is associated with decreased strength, slower reflexes, and reduced flexibility.

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Description

Test your knowledge of the muscular system with this quiz focused on the key types and features of muscular tissue. Explore skeletal, cardiac, and smooth muscle characteristics in detail. Perfect for students studying anatomy or physiology!