Muscle

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

• Sarcoplasmic reticulum

• Transverse Tubules

• Mitochondria

• Motor end Plates

Myofibrils are composed primarily of

• Actin and Myosin

• ATP and ADP

• Troponin

• Tropomyosin

The enzyme cholinesterase cause acetylcholine to

• bind to actin

• secret from the motor end plate

• decompose

• form cross bridges

A muscle cramp is likely due to a lack of

• Actin

• Myosin

• ATP

• ADP

Smooth Muscle

• are composed of sheets of muscle cells

• are under conscious control

• is present in the walls of the stomach and intestines

• none of these

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

The all-or-none response means

• all of the muscles in a region contract together

• all of the muscle fibers within a muscle contract together

• when a muscle fiber contracts, it contracts completely

• when a muscle fiber contracts, all of its ATP is changed to ADP

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

When a muscle undergoes atrophy in response to disuse

• there is a reduction in capillary networks

• the number of mitochondria decreases

• the size of actin and myosin filaments decreases

• all of these

Muscle fatigue is most likely due to an accumulation of

• citric acid

• lactic acid

• creatine

• myosin

Tags

NGSS.HS-LS2-3