Muscle Contraction

Which of the following muscles is considered the largest muscle in the human body?

• Sartorius

• Gluteus Maximus

• Stapedius

• Pectoralis Major

What is the primary action of skeletal muscles when they contract?

• Push bones away from each other.

• Generate heat for body temperature regulation.

• Pull bones closer to their origin.

• Extend themselves beyond their resting state.

True or False: Skeletal muscles pull their insertion towards their origin when they contract.

• True

• False

What is the term for the muscles primarily responsible for producing a specific movement?

• Antagonists

• Synergists

• Fixators

• Prime Movers

During a movement, what is the role of antagonist muscles?

• To directly assist the prime movers in generating force., maximizing strength

• To work in parallel to the prime movers, enabling hyperflexion.

• To work in reverse of the prime movers, preventing overextension.

• To initiate the movement before the prime movers engage, preventing muscle strains.

What is a motor unit composed of?

• A single muscle fiber and multiple motor neurons.

• A group of muscle fibers and a single motor neuron.

• Multiple muscle fibers and multiple motor neurons.

• A single muscle fiber and a single motor neuron.

Muscles responsible for fine motor control, such as those in the eyes and fingers, typically have what type of motor units?

• Large motor units with high innervation ratios.

• Small motor units with low innervation ratios.

• Motor units that can both push and pull.

• Motor units that only contain fast-twitch fibers.

Which phase of a muscle twitch involves the release of calcium ions and the initiation of cross-bridge cycling, but no force production yet?

• Period of Contraction

• Relaxation Period

• Latent Period

• Refractory Period

What happens during the relaxation period of a muscle twitch?

• Myosin heads bind to actin, generating tension.

• Calcium ions are pumped back into the sarcoplasmic reticulum.

• Sodium ions are pumped back into the sarcoplasmic reticulum.

• The muscle fiber shortens to its maximum extent, generating potential energy.

What are graded muscle responses?

• Responses that vary in strength.

• Responses that are always maximal.

• Responses that only occur in smooth muscle.

• Responses that are unaffected by stimulus frequency.