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Muscle MCQs

Muscle MCQs. The fibrous connective tissue sheath which encloses a whole muscle is called the. endomysium. perimysium. epimysium. sarcolemma. Within a muscle the fibers are divided into larger bundles called ____, each surrounded by its own connective tissue sheath. sarcomeres

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Muscle MCQs

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  1. Muscle MCQs

  2. The fibrous connective tissue sheath which encloses a whole muscle is called the • endomysium. • perimysium. • epimysium. • sarcolemma.

  3. Within a muscle the fibers are divided into larger bundles called ____, each surrounded by its own connective tissue sheath. • sarcomeres • sarcolemmas • myofibers • fascicles

  4. The term ____ is synonymous with muscle cell. • myofiber • sarcomere • myofibril • fascicle

  5. Skeletal muscle cells are unusual in that they • lack smooth endoplasmic reticulum. • have no mitochondria. • have multiple nuclei. • depend entirely on anaerobic respiration.

  6. Skeletal muscle cells are striated that is, they have alternating dark and light bands called ____, respectively. • A and I bands • H and M bands • Z and M lines • I and H bands

  7. The I bands of skeletal muscle fibers each have a dark line in the middle called a • D line. • H line. • Z line. • X line.

  8. A muscle is stimulated and exhibits a contraction (twitch). Before this twitch is over, it is stimulated again, and a second twitch occurs "piggyback" on the first one and causes a higher contraction strength. This phenomenon is called • tetanus. • graded contraction. • summation. • isometric contraction.

  9. If enough muscle fibers contract to make the muscle as a whole shorten in length, the muscle is said to exhibit • complete tetanus. • graded contraction. • isometric contraction. • isotonic contraction.

  10. A motor unit is • the motor end plate where a nerve fiber synapses with a muscle fiber. • one motor neuron and all muscle fibers to which it leads. • a spinal reflex arc. • a sarcomere.

  11. The contraction strength of a whole muscle varies in accordance with the • number of motor units activated. • innervation ratio. • amount of calcium released from the sarcoplasmic reticulum. • amplitude of the arriving action potentials.

  12. Contraction in a muscle occurs because the • thin filaments get shorter. • thick filaments get shorter. • thin filaments slide between the thick filaments. • titin proteins pull on opposite ends of the sarcomere.

  13. The region of the resting sarcomere where the thin and thick filaments are overlapping is seen in the • narrow dark line known as the Z line. • dark color of the I bands. • lighter region of the I bands. • dark color of the A bands.

  14. The thick filaments of muscle are composed of • tropomyosin. • actin. • troponin. • myosin.

  15. The basic unit of muscle contraction is the sarcomere, which is • one A band and the adjacent I band. • the distance from one Z line to the next. • equivalent to a fascicle of muscle fibers. • equivalent to one of the myofibrils within a muscle fiber.

  16. During contraction the • actin filaments bind to the myosin filaments. • I bands shorten. • sarcomeres do not change in length. • size of the H zone increases.

  17. The ability of myosin to interact with actin is regulated by the binding of • Ca2+ to troponin. • ATP to actin. • Ca2+ to tropomyosin. • the binding of titin to ATP.

  18. The thin filaments of a muscle fiber consist of all of the following except • tropomyosin. • myosin. • troponin. • actin.

  19. The calcium that binds to troponin to activate muscle contraction comes from storage sites located in the • T tubules. • extracellular fluid. • synaptic vesicles of the motor neuron. • sarcoplasmic reticulum.

  20. Excitation-contraction coupling refers especially to the • events at the neuromuscular junction where a motor fiber excites a muscle cell. • propagation of action potentials from the neuromuscular junction to the T tubules. • calcium release and binding to troponin molecules. • attachment of myosin cross bridges to the thin filaments.

  21. ATP is required by two different processes that are necessary to the contraction and relaxation of a muscle: the interaction between the thick and thin filaments of the sarcomeres, and the • binding of acetylcholine to the motor end plate. • release of calcium from the sarcoplasmic reticulum. • movement of the troponin-tropomyosin complex. • reuptake of calcium by the sarcoplasmic reticulum.

  22. In skeletal muscle contraction Ca2+ must bind to troponin for contraction to occur and in order for the muscle to relax the Ca2+ must • diffuse out of the cell. • be actively transported into the cell. • be actively transported into the sarcoplasmic reticulum. • be bound to tropomyosin until the next contraction.

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