The outermost layer of connective tissue of a
muscle is the:

• fascicle.
• epimysium.
• endomysium.
• perimysium.

The thick myofibril filament of a sarcomere is
composed of a protein:

• actin.
• myosin.
• sarcolemma.
• titin.

The muscle primarily responsible for a movement
is the:

• prime mover (agonist).
• synergist.
• antagonist.
• origin.

The neuron and the collection of muscle fibers it innervates is called the:

• neural impulse.
• motor neuron.
• muscle fiber.
• motor unit.

The functional contractile unit within muscle fiber is the:

• sarcoplasm.
• sarcolemma.
• sarcomere.
• sarcoplasmic reticulum.

The functional contractile unit within muscle fiber is the:

• actin.
• nucleus.
• mitochondrion.
• sarcomere.

According to the sliding filament model, muscle
contraction begins when:

• calcium ion concentration increases exposing binding sites.
• myosin heads pull on actin filaments.
• ATP splits to form ADP and P.
• myosin heads release the actin filaments

Cardiac muscle

• contracts as a syncytium.
• excites itself.
• is only in the heart.
• all of these

Oxygen debt in muscles may develop because of:

• the inability of respiratory and circulatory systems to supply enough oxygen to skeletal muscles when used strenuously for a minute or two.
• the inability of myoglobin molecules to store enough oxygen when skeletal muscles are used strenuously for a minute or two.
• too much oxygen used in forming pyruvic acid when skeletal muscles are contracted strenuously for a minute or two.
• too high a concentration of oxygen in the atmosphere.

Tags

NGSS.HS-LS1-7

NGSS.HS-LS2-3

A weightlifter uses muscles so the muscles exert more than 75% of their maximum tension, this stimulates:

• an increase in slow, fatigable white fibers.
• muscle fibers developing new filaments of actin and myosin.
• shrinking of skeletal muscle.
• conversion of skeletal to smooth muscle.