Nervous Control of Muscle Contraction Quiz

What initiates the contraction of muscle fibers?

• Electrical impulses from neurons

• Chemical signals from the brain

• Mechanical pressure on the muscle

• Thermal changes in the environment

What is a motor unit composed of?

• Multiple neurons and a single muscle fiber

• A single muscle fiber

• A neuron and all muscle fibers in a muscle

• A neuron and a group of muscle fibers it innervates

According to the all-or-none law, what happens if the electrical impulse is insufficient?

• All fibers in the motor unit contract partially

• Some fibers in the motor unit contract

• None of the fibers in the motor unit contract

• All fibers in the motor unit contract fully

Which type of muscle fibers are recruited first to meet force demands?

• Type 1 fibers

• All fiber types simultaneously

• Type 2a fibers

• Type 2x fibers

What is the primary reason for recruiting type 1 fibers first?

• They produce the most force

• They work anaerobically

• They have minimal byproducts and work aerobically

• They are the largest fibers

What happens if type 1 and type 2a fibers together cannot meet the force requirement?

• The body recruits more type 1 fibers

• The body stops trying to produce force

• The body recruits more type 2a fibers

• Type 2x fibers are recruited

What color are type 1 muscle fibers typically represented as in diagrams?

• Green

• Blue

• Red

• White

Why are type 2x fibers white in diagrams?

• They are the smallest fibers

• They have very little blood supply

• They are used for aerobic exercise

• They have a high blood supply

What is required for a muscle to reach maximal force production?

• Recruitment of only type 2x fibers

• Recruitment of only type 1 fibers

• Recruitment of only type 2a fibers

• Recruitment of all motor units

What is the role of type 2a fibers in muscle contraction?

• They are the first to be recruited

• They have some aerobic capacity and produce more force than type 1 fibers

• They are not involved in muscle contraction

• They are only used for maximal force production