Muscles

The threshold potential results from the balance between outward K+ leakage & inward Na+ leakage.

• True

• False

Multiunit muscles are found in the walls of hollow visceral organs.

• True

• False

Which four properties of muscle tissue facilitate the functioning of muscles?

• Contractility, Extensibility, Elasticity, Irritability

• Contractility, Synchronization, Extensibility, Plasticity

• Tunability, Irritability, Contractility, Adaptability

• Elasticity, Plasticity, Synchronization, Adaptability

What is released from the sarcoplasmic reticulum into the sarcoplasm when a muscle contracts?

• Myoglobin

• Na+

• Ca 2+

• ATP

This is the middle region of the thick filaments that do not overlap the thin filaments.

• M line

• H zone

• Z disc

• I band

During contraction, myosin cross bridges pull thick filaments toward the center of each sarcomere.

• True

• False

From least to greatest, which kind of muscle tissue releases the most Ca 2+?

• Smooth, Skeletal, Cardiac

• Cardiac, Skeletal, Smooth

• Skeletal, Cardiac, Smooth

• Smooth, Cardiac, Skeletal

Most muscles cross at least one:

• Tendon

• Ligament

• Bone

• Joint

When the muscle fibers are excited, the ___ are free to bind to ___ molecules on the thin filaments.

• G-actin subunits, ATP

• Ca 2+, troponin

• Na+, myoglobin

• Ca 2+, creatine kinase

The H zone of the A band appears less dense because the thin filaments do not extend into this region.

• True

• False