Motor Units, Muscle Spindles and Golgi Tendon Organs

What is a motor unit?

• A single muscle fiber

• A motor neuron and all the muscle fibers it innervates

• A sensory receptor in the muscle

• A group of tendons connected to a single bone

What law describes how a motor unit either fully contracts or does not contract at all?

• Henneman’s Size Principle

• All-or-none law

• The stretch reflex

• Autogenic inhibition

Which of the following types of motor units are responsible for precise, fine movements?

• Large motor units

• Small motor units

• Intermediate motor units

• Fast glycolytic motor units

How are motor units recruited during increasing levels of force production?

• Larger motor units are always recruited first.

• All motor units activate at the same time.

• Small motor units are recruited first, followed by larger motor units.

• Only the fast-twitch motor units are activated.

What is the primary function of muscle spindles?

• To detect changes in muscle tension

• To prevent overstretching of the muscle

• To signal the brain during muscle fatigue

• To control voluntary muscle contractions

Muscle spindles are most sensitive to which of the following?

• Muscle length and the rate of stretch

• Blood flow to the muscle

• Muscle tension during contraction

• Oxygen consumption during exercise

What reflex is initiated when a muscle spindle detects a rapid stretch?

• Golgi reflex

• Tendon reflex

• Stretch reflex

• Autogenic inhibition

In which situation would muscle spindles play the most significant role?

• Preventing excessive muscle tension during a heavy lift

• Detecting when a muscle is quickly overstretched

• Allowing smooth, controlled relaxation of a muscle

• Facilitating autogenic inhibition during flexibility training

What is the main role of a Golgi tendon organ (GTO)?

• To detect changes in muscle length

• To prevent injury by reducing excessive muscle tension

• To trigger the stretch reflex

• To increase muscle contraction during exercise

What response occurs when the Golgi tendon organ detects excessive tension in a muscle?

• The muscle contracts more forcefully.

• The motor units are recruited more rapidly.

• The muscle relaxes to prevent injury.

• The antagonist muscle contracts.