32 Questions
What is the primary source of ATP for glycolytic fibers?
Glycolysis
What is the function of myoglobin in oxidative fibers?
To store oxygen
Which type of fiber has a larger diameter and less myoglobin?
Glycolytic fiber
What is the characteristic of fast-twitch fibers in terms of muscle contractions?
They enable brief, rapid, powerful contractions
What is the main difference between oxidative and glycolytic fibers in terms of energy supply?
Oxidative fibers use aerobic respiration, while glycolytic fibers use glycolysis
Which type of meat is composed of glycolytic fibers?
Light meat
What is the main difference between slow-twitch and fast-twitch fibers in terms of contraction speed?
The rate at which their myosin heads hydrolyze ATP
What type of fibers are exclusively found in the muscles of the eye and hand?
Fast-twitch fibers
What happens to some fast glycolytic fibers when a muscle is used repeatedly for activities requiring high endurance?
They become fast oxidative fibers
What is unique about the muscles surrounding the gas-filled swim bladder of the male toadfish?
They can contract and relax more than 200 times per second
What is the main difference between vertebrate cardiac muscle and skeletal muscle?
Vertebrate cardiac muscle can initiate rhythmic depolarization and contraction without nervous system input
What is the purpose of intercalated disks in vertebrate cardiac muscle?
To electrically couple each cardiac muscle cell to the adjacent cells
What is a characteristic of smooth muscle cells in vertebrates?
Their thick filaments are scattered throughout the cytoplasm
How do smooth muscle cells regulate contraction?
Through the binding of Ca2+ to calmodulin
What is a difference between smooth muscle and striated muscle?
Smooth muscle contracts and relaxes more slowly
What is a function of dense bodies in smooth muscle cells?
To attach thin filaments
What is the primary function of myoglobin in oxidative fibers?
To bind oxygen more tightly
What is the main difference between oxidative and glycolytic fibers in terms of their structure?
The amount of myoglobin
Which type of fibers are specialized for brief, rapid, and powerful contractions?
Fast-twitch fibers
What is the role of many mitochondria in oxidative fibers?
To enable efficient use of a steady energy supply
What is the characteristic of dark meat in poultry and fish?
It is composed of oxidative fibers
Which type of fibers are more prone to fatigue?
Glycolytic fibers
What is the reason for the difference in contraction speed between slow-twitch and fast-twitch fibers?
The rate of ATP hydrolysis by myosin heads
What is the characteristic of cardiac muscle cells that allows them to initiate rhythmic depolarization and contraction?
The ability to initiate rhythmic depolarization and contraction without nervous system input
What is the function of Ca2+ in smooth muscle cells?
To activate the myosin head and enable cross-bridge activity
What is the difference in the way Ca2+ regulates contraction in smooth muscle cells compared to striated muscle cells?
Smooth muscle cells have a different mechanism of Ca2+ regulation
What is the result of repeated use of a muscle for activities requiring high endurance?
The muscle becomes more resistant to fatigue
What is unique about the muscles surrounding the gas-filled swim bladder of the male toadfish?
They can contract and relax more than 200 times per second
What is the function of dense bodies in smooth muscle cells?
To anchor thin filaments to the plasma membrane
What is the primary difference between skeletal muscle and cardiac muscle?
Skeletal muscle is voluntary, while cardiac muscle is involuntary
What is the difference in the contraction speed between slow-twitch and fast-twitch fibers?
Fast-twitch fibers contract five times faster than slow-twitch fibers
What is the characteristic of smooth muscle cells that allows them to contract and relax more slowly than striated muscle cells?
Less myosin than striated muscle fibers
Learn about the different types of skeletal muscle fibers, including oxidative and glycolytic fibers, and how they are classified based on ATP source and contraction speed.
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