Human Muscle Physiology

Which of the following best describes actin filaments?

• A thin filament made of two intertwining strands whose subunits bind together like beads on a string
• A thick filament that looks like two golf clubs twisted together
• A small, globular regulatory protein that holds another protein in place
• A long, ropelike regulatory protein that spirals around another protein, covering its active sites

The storage and release of calcium ions is the key function of the:

• sarcolemma.
• sarcoplasm.
• sarcoplasmic reticulum.
• mitochondrion.

Which of the following is NOT a major function of muscle tissue?

• generating heat through contractions
• stabilizing joints
• promoting movement of body structures
• storing energy

Which of the following statements is TRUE regarding Fast Glycolytic fibers found in skeletal muscle?

• They are small in diameter.
• They are adapted for intense bursts of anaerobically fueled movement.
• They have abundant mitochondria.
• They contract slowly, but are resistant to fatigue.

The Na+/K+ pump helps a muscle cell maintain a state of:

• depolarization.
• propagation.
• resting membrane potential.
• action potential.

Which of the following statements is TRUE regarding Slow Oxidative fibers found in skeletal muscle?

• They are large in diameter.
• They are adapted for intense bursts of anaerobically fueled movement.
• They lack mitochondria.
• They contract slowly, but are resistant to fatigue.

Calcium ions bind to the ___ molecule in skeletal muscle cells.

• actin
• troponin
• tropomyosin
• myosin

This is a band of connective tissue that surrounds whole muscles.

• ligament
• endomysium
• epimysium
• perimysium

Which of the following represents the sequence that muscle action potentials must go through to excite a muscle cell?

• sarcolemma, axon of neuron, T tubules
• T tubules, sarcolemma, myofilament
• muscle fiber, axon of neuron, mitochondria
• axon of neuron, sarcolemma, T tubules

Which of the following functions as a motor protein in all three types of muscle tissue?

• actin
• myosin
• troponin
• titin