Muscle Coordination and Contraction

The (a)   refers to where the muscle attaches to bone but does NOT move or moves less.

The (a)   refers to where the muscle attaches to bone and causes movement.

__________ are "helper muscles" as they assist with doing work and stabilize joints against dislocation.

• Synergists

• Prime movers

• Agonists

• Antagonists

A (a)   consists of a group of muscle fibers that all get their signals from the same single motor neuron. As a result, all muscle fibers act together as a unit.

__________ motor units are found in muscles that perform precise or fine movements. Examples would be those found in the eyes and fingers.

• Small

• Large

• Mixed

A(n) ____________________ is a single stimulus-contraction-relaxation sequence in a muscle fiber. It is a single, short contraction involving only a few motor units.

• twitch

• origin

• recruitment

• antagonist

In a single muscle twitch, the ____________________ occurs when calcium (Ca2+) is being pumped back into the sarcoplasmic reticulum (SR) and actin and myosin stop the binding cycle.

• latent period

• contraction phase

• relaxation phase

In a single muscle twitch, the ____________________ occurs immediately after a muscle fiber has been stimulated by a nerve. Calcium (Ca2+) is released from the sarcoplasmic reticulum (SR). The stimulus has arrived, but NO force/tension is being produced. This is the SHORTEST phase of a single muscle twitch.

• latent period

• contraction phase

• relaxation phase

The image shown is an example of ____________________. This occurs if a second stimulus arrives IMMEDIATELY AFTER the RELAXATION phase has ENDED. The resulting contraction will have a slightly higher tension than the first contraction. Tension rises in stages (like a staircase, hence its name).

• treppe

• wave (temporal) summation

• complete tetanus

• incomplete tetanus

The image shown is an example of ____________________. This happens when another action potential (stimulus) occurs BEFORE the muscle is able to RELAX (before the relaxation phase). MORE calcium (Ca2+) is released resulting in MORE binding sites being revealed. As a result, MORE force is generated in that muscle fiber. In this case, twitches add to each other (get closer together in time).

• treppe

• wave (temporal) summation

• complete tetanus

• incomplete tetanus