Muscle Tissue and Functions

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Questions and Answers

Which of the following is NOT a characteristic of muscle tissue?

Elasticity
Excitability
Contractility
Permeability (correct)

Skeletal muscles are responsible for all locomotion.

True (A)

What are the two types of myofilaments that are essential for muscle contraction?

Actin and myosin

The prefix ______ refers to muscle.

myo Signup and view all the answers

Match the following muscle types with their primary location:

Skeletal muscle = Attached to bone Smooth muscle = On hollow organs, glands, and blood vessels Cardiac muscle = Heart Signup and view all the answers

Which type of muscle is responsible for the contraction of the heart?

Cardiac muscle (C) Signup and view all the answers

Smooth muscle contractions are voluntary.

False (B) Signup and view all the answers

What is the primary function of smooth muscle in the digestive system?

Squeezing or propelling substances (i.e., food, feces) through organs Signup and view all the answers

Each muscle fiber contains a single nucleus.

False (B) Signup and view all the answers

What are the three connective tissue wrappings that surround muscle fibers?

Epimysium, perimysium, and endomysium Signup and view all the answers

The basic functional unit of a muscle fiber is the ______.

sarcomere Signup and view all the answers

Which of the following is NOT a component of the thin filament?

Myosin (B) Signup and view all the answers

Match the following structures with their descriptions:

A band = Dark band composed of thick filaments I band = Light band composed of thin filaments H zone = Central region of the A band containing only thick filaments Z disk = Defines the boundary of a sarcomere M line = Central region of the H zone where thick filaments are linked together Signup and view all the answers

What happens to the width of the I band during muscle contraction?

Decreases (B) Signup and view all the answers

What is the role of ATP in muscle contraction?

ATP provides energy for the myosin heads to bind to actin, detach from actin, and reattach further along the thick filament, causing the sliding of thin filaments. Signup and view all the answers

During muscle contraction, the thick filaments shorten.

False (B) Signup and view all the answers

Muscle cramps are a symptom of muscular dystrophy.

False (B) Signup and view all the answers

The protein ______ is crucial for the structure of muscle fibers and is affected in muscular dystrophy.

dystrophin Signup and view all the answers

Which of the following is a characteristic of the autoimmune disease myasthenia gravis?

It primarily affects the skeletal muscles. (B) Signup and view all the answers

What is sarcopenia?

Sarcopenia is the age-related loss of muscle mass. Signup and view all the answers

Which of the following accurately describes the relationship between muscles and bones during movement?

Muscles contract to pull on bones, causing movement. (B) Signup and view all the answers

Which of the following can help prevent sarcopenia?

Regular exercise. (A) Signup and view all the answers

Muscles always contract in pairs, with one muscle extending the bone and the other flexing it.

True (A) Signup and view all the answers

Match the following disorders with their descriptions:

Poliomyelitis = Viral infection that affects the nerves controlling skeletal muscle movement Muscular Dystrophies = Group of genetic disorders that cause progressive muscle weakness and degeneration Myasthenia Gravis = Autoimmune disease affecting the neuromuscular junction Tetanus = Bacterial infection that causes painful muscle spasms Signup and view all the answers

The attachment of a muscle to a more stationary bone is called the , while the attachment to the more movable bone is called the .

origin, insertion Signup and view all the answers

Describe the two primary ways in which muscles can attach to bones.

Muscles can attach to bones either directly, where the epimysium of the muscle is fused to the periosteum of the bone, or indirectly, where connective tissue wrappings extend beyond the muscle as a tendon or aponeurosis. Signup and view all the answers

Match the following terms with their respective descriptions:

Origin = The attachment point of a muscle to a more moveable bone. Insertion = The attachment point of a muscle to a more stationary bone. Tendon = A dense fibrous connective tissue that attaches muscle to bone. Aponeurosis = A broad, flat sheet of connective tissue that attaches muscle to bone. Signup and view all the answers

Which of the following is NOT a component found in a skeletal muscle?

Cartilage (A) Signup and view all the answers

Each skeletal muscle fiber is innervated by multiple nerve endings, allowing for precise control of muscle contraction.

False (B) Signup and view all the answers

Why do contracting muscle fibers require a continuous supply of oxygen and nutrients?

Contracting muscle fibers need oxygen for energy production and nutrients such as glucose to fuel their contractions. Wastes produced during contraction must also be removed efficiently. Signup and view all the answers

Which type of muscle has smaller motor units, allowing for finer control of movement?

Muscles controlling fine movements (C) Signup and view all the answers

A single motor unit can cause a strong contraction of the entire muscle.

False (B) Signup and view all the answers

The ______ is the final trigger for muscle contraction.

rise in intracellular Ca2+ levels Signup and view all the answers

What are the four main steps involved in the contraction of a skeletal muscle?

The four main steps involved in the contraction of a skeletal muscle are: 1. Cross bridge attachment - myosin cross bridge attaches to actin filament; 2. Working (power) stroke - myosin head pivots and pulls actin filament toward M line; 3. Cross bridge detachment - ATP attaches to myosin head and the cross bridge detaches; 4. “Cocking” of the myosin head - energy from hydrolysis of ATP cocks the myosin head into the high energy state Signup and view all the answers

Match the following terms related to muscle contraction with their descriptions:

Cross bridge attachment = Myosin head attaches to actin filament Working (power) stroke = Myosin head pivots and pulls actin towards the M line Cross bridge detachment = ATP binds to the myosin head, causing detachment Cocking of myosin head = ATP hydrolysis provides energy for the myosin head to return to its high-energy position Signup and view all the answers

Muscle fatigue occurs primarily due to a depletion of glycogen stores in the muscle.

False (B) Signup and view all the answers

What are the physiological changes that occur in a muscle during oxygen debt?

During oxygen debt, the muscle needs to replenish oxygen reserves, convert lactic acid to pyruvic acid, replace glycogen stores, and resynthesize ATP and CP reserves. Signup and view all the answers

Which of the following is NOT a contributing factor to muscle fatigue ?

Increased blood flow to the muscle (E) Signup and view all the answers

Flashcards

Muscle Functions

Roles include stabilizing joints, producing movement, and generating heat.

Characteristics of Muscle Tissue

Excitability, contractility, extensibility, and elasticity are key traits.