Muscle Structure

The functional contractile unit within a muscle fiber is called the

• sarcomere

• fascia

• sarcoplasm

• tendon

The cytoplasm of a muscle cell is called the

• myosin

• actin

• fascia

• sarcoplasm

Structure B is known as the thin filaments of the sarcomere, what is another name for the thin filaments?

• myosin

• actin

• fascia

• myofibril

Structure C is known as the thick filament of the sarcomere, it is also known as

• myosin

• actin

• fascia

• myofibrils

Structure A is on either side of the sarcomere, it is called the

• A band

• I band

• Z disc

• fascia

Tags

NGSS.HS-LS1-2

The unit between A and A is called

• a sarcomere

• The I band

• the Z disc

• fascia

The impulse that triggers a contraction travels deep into a muscle fiber by means of

• Sarcoplasmic reticulum

• Transverse Tubules

• Mitochondria

• Motor end Plates

Compared to skeletal muscle, smooth muscle

• contracts more slowly and relaxes more slowly

• contracts more slowly and relaxes more rapidly

• contracts more rapidly and relaxes more slowly

• contracts more rapidly and relaxes more rapidly

Rigor mortis that occurs in skeletal muscles a few hours after death is due to

• excessive ATP, which prevents muscle relaxation

• lack of ATP, which prevents muscle relaxation

• excessive ATP, which causes muscle contraction

• None of these

What is the structure that stores the Calcium in the muscle cell.  

• Sarcoplasm
• Sarcolemma
• Sarcoplasmic Reticulum
• Myoglobin