Quick Quiz: Smooth Muscle vs. Skeletal Muscle

Review your notes muscle physiology and then do the following quiz. For each statement, type "smooth" if it is true for smooth muscle only, "skeletal" if it is true for skeletal muscle only, or "both" if it is true for both smooth and skeletal muscle.


 Fill-in Answer Correct False Correct Answer
1. Force generation depends on cross-bridge cycling.
2. An increase in Ca++ in the cytosol is required for contraction.
3. T-tubules are necessary for excitation-contraction coupling.
4. When myosin light chain kinase (MLCK) activity is greater than myosin light chain phosphatase (MLCP) activity, cross-bridge cycling can occur.
5. The sarcoplasmic reticulum is a source of Ca++ ions.
6. Troponin is a regulatory protein on the thin filament.
7. Neurons that synapse onto muscle cells can release the neurotransmitter acetylcholine.
8. Neurons that synapse onto muscle cells can directly inhibit the muscle cell.
9. The synapse between the neuron and the muscle cell has a high safety factor.
10. A major mechanism of Ca++ release from the SR is via binding of IP3 to ligand-gated Ca++ channels.
11. Contraction velocity is determined by the level of myosin ATPase activity.
12. Relaxation occurs as Ca++ is pumped out of the cytosol.
13. The extracellular fluid can be a source of Ca++ ions.
14. Muscle cells are innervated by somatic efferent neurons.


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