ANATOMY: Muscle contractions

Which of the following is NOT true about oxygen debt?

• During exertion, oxygen has been depleted

• In recovery, we owe the body some oxygen.

• Oxygen demands remain elevated in order to reduce high levels of lactic acid

• This is the biggest reason someone passes out after exerting a lot of energy?.

Tags

NGSS.HS-LS2-3

These projections, or myosin heads, that are found on the thick filaments are called _____.

• cross bridges

• Z lines

• A bands

• actin tails

What happens during the power stroke of muscle contraction?

• break down of ATP occurs at the myosin head so that it is ready to pull at actin again

• cross bridges attach to actin filaments and pull them toward the middle of the sarcomere

Tags

NGSS.HS-LS1-7

when a muscle is unable to contract even through it is still being stimulated

• oxygen debt

• muscle fatigue

• motor units

System that provides channels for ion flow throughout the muscle fibers to facilitate the propagation of an action potential.

• transverse tubules

• motor units

• sarcoemeres

• sarcoplasmic reticulum

A motor neuron and all of the muscle fibers it innervates/ controls

• transverse tubules

• motor units

• sarcoemeres

• sarcoplasmic reticulum

What ions free the actin strands and allow muscle contraction to occur?

• POTASSIUM

• CALCIUM

• SODIUM

What energy molecule binds to the myosin heads and allows the detachment from actin?

• GLUCOSE

• ADP

• ATP

• CALCIUM

Microfilaments of actin and myocin in repeating subunits.

• MYOFIBRILS

• Z LINES

• SARCOMERES

• SARCOLEMMA

The contractile unit of a myofibril consisting of Z-lines, A-bands, and I-bands.

• A BANDS

• Z LINES

• SARCOMERES

• SARCOLEMMA