Gatos
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Publicado: 21 de febrero de 2013
Muscle Physiology Quiz
The same comments presented with earlier quizzes also apply to this one.
True or False Questions:
1. Myofibrils are repeating subunits (about 2-3 microns in length) that are arranged end-to-end to form sarcomeres.
2. The A band consists of thin filaments that do not overlap with thick filaments.
3. The transeverse tubular system (T system) is anintracellular organelle.
4. The sarcoplasmic reticulum (SR) is an intracellular organelle.
5. The mechanism by which Ca2+ is released from the SR is identical in skeletal muscle and cardiac muscle.
6. Thick filaments are composed of myosin and thin filaments are primarily composed of actin.
7. Tropomyosin binds Ca2+ causing a conformational change that causes troponin to uncover bindingsites on actin for crossbridge attachment.
8. In skeletal and cardiac muscle, in order for a myosin crossbridge to bind to actin the crossbridge must first split a molecule of ATP.
9. In skeletal and cardiac muscle, in order for a myosin crossbridge to detach from actin the crossbridge must first bind a molecule of ATP.
10. Parvalbumin is more abundant in fast fiber types than in slowoxidative fibers.
11. The dystrophin-glycoprotein complex is a group of cytoskeletal proteins that occur exclusively in the Z lines of skeletal and cardiac muscle.
12. The absence of dystrophin from skeletal muscle results in Duchenne muscular dystrophy.
13. A patient who has the same type of genetic defects found in Duchenne muscular dystrophy but associated with the encoding of cardiacmuscle proteins will display a hypertrophic cardiomyopathy.
14. Skeletal muscle normally (i.e., within the body) works at sarcomere lengths less than 2.0 microns, while cardiac muscle normally works at sarcomere lengths greater than 2.6 microns.
15. An isometric contraction is one in which the muscle is prevented from shortening.
16. Normally the frequency of action potentials can affect theamount of tension developed by skeletal muscle but not by cardiac muscle (i.e., skeletal muscle displays summation of tension, but cardiac muscle does not).
17. Motor units generally contain more skeletal muscle fibers in whole muscles designed to produce precise delicate movements than in whole muscles designed to produce coarse powerful movements.
18. Slow oxidative fibers contain lessmyoglobin than fast glycolytic fibers.
19. Desmosomes are mechanical adhering junctions found in the intercalated discs of cardiac muscle.
20. The rapid upstroke (phase 0) of action potentials in ventricular and atrial myocytes results from the opening of Ca2+ channels.
21. Action potentials of atrial myocytes normally have a shorter duration than action potentials of ventricular myocytes.22. The AV node is normally the pacemaker for the whole heart.
23. In the SA node and AV node the upstroke of the action potential results from the opening of Ca2+ channels.
24. Hyperkalemia results in the resting potential of cardiac muscle cells becoming more negative and can therefore cause these cells to fail to reach threshold.
25. Activated (1 adrenergic receptors in the heartactivate G-proteins that inhibit adenylyl cyclase and reduce myoplasmic levels of cAMP.
26. M2 muscarinic receptors in the heart bind ACh causing a decrease in heart rate and decreased force of contraction of the atria.
27. Norepinephrine released from sympathetic nerve terminals in the heart cause a decrease in the rate of pacemaker activity.
28. The Na+/Ca2+ exchanger is abundant in thesarcolemma of cardiac muscle cells, but much less common or absent in skeletal muscle.
29. The inotropic state of a cardiac muscle fiber is always increased when the fiber is stretched to longer lengths.
30. Starling’s Law of the Heart refers to increased force of contraction resulting from increased myoplasmic Ca2+ during ventricular systole.
31. Gap junctions are more common in...
The same comments presented with earlier quizzes also apply to this one.
True or False Questions:
1. Myofibrils are repeating subunits (about 2-3 microns in length) that are arranged end-to-end to form sarcomeres.
2. The A band consists of thin filaments that do not overlap with thick filaments.
3. The transeverse tubular system (T system) is anintracellular organelle.
4. The sarcoplasmic reticulum (SR) is an intracellular organelle.
5. The mechanism by which Ca2+ is released from the SR is identical in skeletal muscle and cardiac muscle.
6. Thick filaments are composed of myosin and thin filaments are primarily composed of actin.
7. Tropomyosin binds Ca2+ causing a conformational change that causes troponin to uncover bindingsites on actin for crossbridge attachment.
8. In skeletal and cardiac muscle, in order for a myosin crossbridge to bind to actin the crossbridge must first split a molecule of ATP.
9. In skeletal and cardiac muscle, in order for a myosin crossbridge to detach from actin the crossbridge must first bind a molecule of ATP.
10. Parvalbumin is more abundant in fast fiber types than in slowoxidative fibers.
11. The dystrophin-glycoprotein complex is a group of cytoskeletal proteins that occur exclusively in the Z lines of skeletal and cardiac muscle.
12. The absence of dystrophin from skeletal muscle results in Duchenne muscular dystrophy.
13. A patient who has the same type of genetic defects found in Duchenne muscular dystrophy but associated with the encoding of cardiacmuscle proteins will display a hypertrophic cardiomyopathy.
14. Skeletal muscle normally (i.e., within the body) works at sarcomere lengths less than 2.0 microns, while cardiac muscle normally works at sarcomere lengths greater than 2.6 microns.
15. An isometric contraction is one in which the muscle is prevented from shortening.
16. Normally the frequency of action potentials can affect theamount of tension developed by skeletal muscle but not by cardiac muscle (i.e., skeletal muscle displays summation of tension, but cardiac muscle does not).
17. Motor units generally contain more skeletal muscle fibers in whole muscles designed to produce precise delicate movements than in whole muscles designed to produce coarse powerful movements.
18. Slow oxidative fibers contain lessmyoglobin than fast glycolytic fibers.
19. Desmosomes are mechanical adhering junctions found in the intercalated discs of cardiac muscle.
20. The rapid upstroke (phase 0) of action potentials in ventricular and atrial myocytes results from the opening of Ca2+ channels.
21. Action potentials of atrial myocytes normally have a shorter duration than action potentials of ventricular myocytes.22. The AV node is normally the pacemaker for the whole heart.
23. In the SA node and AV node the upstroke of the action potential results from the opening of Ca2+ channels.
24. Hyperkalemia results in the resting potential of cardiac muscle cells becoming more negative and can therefore cause these cells to fail to reach threshold.
25. Activated (1 adrenergic receptors in the heartactivate G-proteins that inhibit adenylyl cyclase and reduce myoplasmic levels of cAMP.
26. M2 muscarinic receptors in the heart bind ACh causing a decrease in heart rate and decreased force of contraction of the atria.
27. Norepinephrine released from sympathetic nerve terminals in the heart cause a decrease in the rate of pacemaker activity.
28. The Na+/Ca2+ exchanger is abundant in thesarcolemma of cardiac muscle cells, but much less common or absent in skeletal muscle.
29. The inotropic state of a cardiac muscle fiber is always increased when the fiber is stretched to longer lengths.
30. Starling’s Law of the Heart refers to increased force of contraction resulting from increased myoplasmic Ca2+ during ventricular systole.
31. Gap junctions are more common in...
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