What is the role of tropomyosin in skeletal muscles?
A) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
Which muscle cells have the greatest ability to regenerate?
A) smooth
Most skeletal muscles contain ________.
B) a mixture of fiber types
Fatigued muscle cells that recover rapidly are the products of ________.
B) intense exercise of short duration
The strongest muscle contractions are normally achieved by ________.
A) increasing the stimulation up to the maximal stimulus
Which of the following would be recruited later in muscle stimulation when contractile strength increases?
D) motor units with larger, less excitable neurons
Which of the following is not a usual result of resistance exercise?
D) increase in the number of muscle cells
Excitation-contraction coupling requires which of the following substances?
B) Ca2+ and ATP
Which of the following is a factor that affects the velocity and duration of muscle contraction?
C) load on the fiber
Myoglobin ________.
C) stores oxygen in muscle cells
What structure in skeletal muscle cells functions in calcium storage?
C) sarcoplasmic reticulum
What does oxygen deficit represent?
D) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the events of excitation-contraction coupling occur.
D) latent
Creatine phosphate functions in the muscle cell by ________.
C) storing energy that will be transferred to ADP to resynthesize ATP
What controls the force of muscle contraction?
D) multimotor unit summation
The major function of the sarcoplasmic reticulum in muscle contraction is to ________.
B) regulate intracellular calcium concentration
What produces the striations of a skeletal muscle cell?
C) the arrangement of myofilaments
Which of the following are composed of myosin?
C) thick filaments
During muscle contraction, myosin cross bridges attach to which active sites?
C) actin filaments
Which of the following surrounds the individual muscle cell?