Anatomy Exam 3 Practice

The ability of muscular tissue to respond to certain stimuli by producing action

potentials is:

• Elasticity

• Contractibility

• Excitability

• Stability

• Extensibility

The ability of muscular tissue to contract forcefully when stimulated is:

• Excitability

• Contractibility

• Elasticity

• Extensibility

• Stability

The ability of muscular tissue to be stretched without being damaged is:

• Stability

• Contractibility

• Elasticity

• Extensibility

• Excitability

Which of the following is FALSE regarding skeletal muscle fibers (cells)?

• The cells are cylindrical and are arranged in parallel fashion

• The myofibrils are arranged at right angles to the long axis of the cell, creating cross striations.

• Each fiber is a single cell with a hundred or more nuclei.

• A skeletal muscle fiber may be up to 30 cm (12 in.) long.

Which of the following is TRUE of myosin

• It is located in the A band of the sarcomere

• It binds to tropomyosin during contraction

• It forms thick filament

• The molecules are helix shaped

In skeletal muscle, the sarcoplasmic reticulum (SR):

• forms transverse (T) tubules

• is similar to the Golgi complex

• contains extracellular fluid

• releases Ca²⁺ to trigger contraction

Compared to skeletal muscle, cardiac muscle differs in that

• has branching cells

• has different arrangement of thick and thin filaments

• contracts for shorter periods of time

• has a short refractory period

Between the ages of 30 and 50, humans undergo a slow, progressive loss of skeletal

muscle mass as it is replaced largely by fibrous connective tissue and adipose tissue.

• An estimated 10 percent of muscle mass is lost during these years. In part,

  this decline may be due to decreased levels of physical activity.

• No significant change in skeletal muscle mass or composition.

• An increase in skeletal muscle mass, replaced by additional muscle fibers.

• An increase in skeletal muscle mass, with enhanced muscle strength.

Accompanying the loss of muscle mass is ...

Another 40 percent of muscle is typically lost between ages

• 50 and 80.

• 40 and 80.

• 50 and 60.

• 40 and 60.