Chapter 10 Section 5

The rapid rise and fall in force produced by a muscle fiber after a single action potential is a(n)

• tetanus.

• unfused tetanus.

• twitch.

• motor end plate potential.

• muscle action potential.

When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This state of maximum tension is called

• incomplete tetanus.

• complete tetanus.

• a twitch.

• wave summation.

• recruitment.

A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in

• incomplete tetanus.

• complete tetanus.

• treppe.

• wave summation.

• recruitment.

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This addition of one twitch to another is called

• incomplete tetanus.

• complete tetanus.

• treppe.

• wave summation.

• recruitment.

What is the contraction in graph (a) called?

• complete tetanus

• incomplete tetanus

• twitch

• wave summation

• treppe

What is thought to happen in a muscle during the response shown in graph (a)?

• It is strengthening with exercise.

• There is a gradual increase in calcium ion concentration in the sarcoplasm.

• It is fatigued and must make repeated efforts to twitch normally.

• It is aged and has lost contractile proteins.

• It is producing more ATP as tension increases.

To produce a contraction similar to the one in graph (b), the muscle

• must be stimulated to the point of fatigue.

• must be stimulated again before it has relaxed from the previous stimulation.

• is excited by a stimulus of increasing intensity.

• must go through a rapid series of isolated twitches.

• generates more and more thin and thick filaments.

Why is there partial relaxation in graph (c)?

• Calcium ion release is slow.

• The muscle is starting to fatigue.

• Stimulation intensity is fluctuating.

• ATP reserves are cycling.

• Nerve stimulation frequency is below maximum.

What is the contraction in graph (d) called?

• complete tetanus

• incomplete tetanus

• twitch

• wave summation

• treppe

A single contraction-relaxation cycle in a muscle fiber produces a(n)

• cramp

• twitch

• tetanic contraction

• action potential

• motor unit