Muscle Spindle Structure and Function Quiz

Play an AI-generated podcast conversation about this lesson

What is the primary function of the Renshaw cells in the spinal cord?

To release acetylcholine and stimulate the muscle spindles
To stimulate gamma motor neurons and increase muscle tone
To inhibit the originally stimulated alpha motor neuron and limit its discharge (correct)
To excite the alpha motor neurons and increase muscle contraction

Which type of motor neuron innervates the intrafusal muscle fibers within the muscle spindle?

Alpha motor neurons
Neither alpha nor gamma motor neurons
Both alpha and gamma motor neurons
Gamma motor neurons (correct)

What is the main difference between the static stretch reflex and the dynamic stretch reflex?

The static stretch reflex involves inhibition of the alpha motor neurons, while the dynamic stretch reflex involves excitation of the alpha motor neurons
The static stretch reflex involves a rapid contraction, while the dynamic stretch reflex involves a gradual contraction
The static stretch reflex is mediated by Ia afferents, while the dynamic stretch reflex is mediated by II afferents
The static stretch reflex maintains muscle tone, while the dynamic stretch reflex occurs during rapid changes in muscle length (correct)

What is the structure of a muscle spindle?

A specialized fusiform structure located in the fleshy part of the muscle (C) Signup and view all the answers

What is the primary way that muscle spindles are stimulated?

By stretch of the muscle fibers (C) Signup and view all the answers

What is the approximate percentage of gamma motor neurons compared to alpha motor neurons in the spinal cord?

Gamma motor neurons represent 30% of the total motor neurons (C) Signup and view all the answers

Which type of nerve fibers supply the contractile part of the nuclear chain in muscle spindles?

Gamma motor neurons (D) Signup and view all the answers

What is the main difference between the dynamic and static stretch reflexes?

The stimulus duration (sudden vs. maintained stretch) (C) Signup and view all the answers

Which part of the muscle spindle is composed of nuclear bag fibers?

The central part (A) Signup and view all the answers

Which method directly stimulates the efferent (motor) nerves to activate muscle spindles?

Stimulation of the efferent motor nerves (D) Signup and view all the answers

What is the primary function of gamma motor neurons in relation to muscle spindles?

Adjust the sensitivity of muscle spindles to stretch (A) Signup and view all the answers

Which of the following accurately describes the structure of a muscle spindle?

It consists of 4-12 intrafusal muscle fibers, with nuclear bag fibers being longer and fewer in number than nuclear chain fibers. (D) Signup and view all the answers

Which of the following statements regarding the innervation of a muscle spindle is correct?

Primary afferents (Ia) arise from the receptor area of nuclear bag fibers, while secondary afferents (II) arise from the receptor area of nuclear chain fibers. (A) Signup and view all the answers

Which of the following types of nerve fibers innervate the contractile part of the nuclear bag fibers in a muscle spindle?

Gamma efferents (dynamic nerve fibers) (C) Signup and view all the answers

Which of the following methods would directly stimulate the muscle spindle and elicit a stretch reflex?

Electrically stimulating the gamma efferents innervating the intrafusal muscle fibers (C) Signup and view all the answers

Which of the following statements accurately describes the function of the stretch reflex mediated by muscle spindles?

It maintains muscle tone and prevents excessive stretching of the muscle. (C) Signup and view all the answers