Chapter 10, Problem 10.3a
Ms. Sanchez was in a motorcycle accident in which she lost the use of her right upper limb muscles due to significant nerve damage. However, when an electrode is inserted into her muscles, they are able to contract. Explain specifically why nerve damage caused her to lose the use of her muscles. Why can they still respond to stimulation from an electrode?
Video transcript
How does a skeletal muscle fiber differ structurally from typical cells?
Some athletes will consume only protein for several days before a competition, which reduces the amount of glycogen in both the muscle fibers and the liver. What effect would this have on their ability to perform activities that require short, powerful bursts of activity? How would it affect their ability to perform endurance activities?
Mark the following statements as true for smooth muscle tissue, cardiac muscle tissue, and/or skeletal muscle tissue.
a. ____Actin attaches to dense bodies.
b. ____Cells are joined by intercalated discs.
c. ____The thick and thin filaments are arranged into sarcomeres.
d. ____The thick filaments contain myosin heads along their entire length.
e. ____The cells depolarize and contract as a unit.
f. ____ Ca2+ binding to troponin is the initiating event of contraction.
g. ____Ca2+ binding to calmodulin is the initiating event of contraction.
h. ____The sarcolemma has a distinct motor end plate.
Match the following terms with the correct definition.
____Z-disc
____Sarcomere
____A band
____H zone
____I band
____M line
a. The dark band containing the entire length of the thick filament
b. The band of proteins in the middle of the H zone
c. The boundary between sarcomeres
d. The functional unit of contraction
e. The middle region of the A band containing only thick filaments
f. The light band containing only thin filaments
Mr. Nasheed has cerebral palsy and suffers severe skeletal muscle spasms as a result of his condition. He is prescribed the drug dantrolene, which prevents the release of Ca2+ from the SR. Explain how this will treat his muscle spasms.
What is the basic mechanism of contraction at the level of myofilaments?