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Questions and Answers

The Golgi tendon organ is most likely to sense which of the following?

Vibration

Pressure

Tension (correct)

Length

Fine touch

Type II sensory afferents from the muscle spindle receptor are attached to which of the following structures?

Nuclear chain fiber (correct)

Gamma S fiber

Dynamic nuclear bag fiber

Extrafusal muscle fiber

Which of the following is most likely to increase the sensitivity of the stretch reflex?

Increased activity in fusimotor (gamma motor neuron) system (correct)

Bending head forward

Increasing activity of medullary reticular nuclei

Cutting dorsal root fibers

Assuming all sensory, motor, and reflex neuronal pathways are intact, skeletal muscle contraction can be caused by stimulation of which of the following?

Type 1a sensory nerve endings Signup and view all the answers

The dynamic response of the muscle spindle receptor can best be described as:

An increase in the activity of the muscle spindle receptor that is proportional to the rate of change in length of the muscle fiber. Signup and view all the answers

Stimulation of type II sensory fibers innervating a muscle spindle:

Will activate an alpha motor neuron connected to the muscle containing the spindle receptor. Signup and view all the answers

Which fiber is responsible for the dynamic response in a muscle spindle receptor?

Nuclear bag fiber Signup and view all the answers

Which of the following best describes the primary function of the Golgi tendon organ?

To sense muscle tension and equalize the contractile force exerted by groups of muscle fibers in a muscle Signup and view all the answers

Activation of a type 1b sensory neuron is most likely to have which of the following effects?

Contraction of muscle fiber associated with this neuron Signup and view all the answers

Muscle contraction can be caused by stimulation of which of the following types of neurons, assuming all sensory, motor, and reflex pathways are intact?

All of these Signup and view all the answers

Type 1a afferents innervate which of the following types of receptors in the muscle spindle apparatus?

All of these Signup and view all the answers

The sensitivity of the stretch reflex can be altered by:

Activity of pontine reticular nuclei. Signup and view all the answers

The stretch reflex initiated by tapping on the patellar tendon causes muscle contraction by activation of which of the following?

Type Ia sensory fibers Signup and view all the answers

Activation of which of the following can lead to muscle contraction under basal conditions?

Type Ia sensory fibers Signup and view all the answers

A muscle spindle is most likely to sense which of the following?

Length Signup and view all the answers

A 30-year-old man with bare feet steps on a broken bottle with his right foot. His right leg immediately lifts while his left leg extends before he can consciously react to the pain. Which of the following best describes the name of this reflex?

Flexor withdrawal reflex Signup and view all the answers

Which of the following best describes the type of reflex arc and sensory receptor for the flexor withdrawal reflex?

Reflex arc: polysynaptic; sensory receptor: nociceptor Signup and view all the answers

Which of the following best describes anterior motor neurons and their innervation targets?

Alpha-extrafusal fibers; gamma-intrafusal fibers Signup and view all the answers

Which of the following best describes the reflex arc and muscle response of the Golgi tendon organ?

Disynaptic reflex arc; relaxation of muscle Signup and view all the answers

Which of the following best describes the transmitter released from Renshaw cells and the primary action of Renshaw cells under normal physiologic conditions?

Glycine—inhibitory Signup and view all the answers

Study Notes

Golgi Tendon Organ

Golgi tendon organs are sensory receptors located in tendons, near the junction of the tendon and muscle.
They are sensitive to muscle tension and play a role in regulating muscle force.

Muscle Spindle Receptors

Muscle spindle receptors are sensory receptors found within skeletal muscles.
They are responsible for sensing muscle length and rate of change in muscle length.

Type II Sensory Afferents

Type II sensory afferents are attached to the nuclear chain fiber of the muscle spindle.

Increasing Sensitivity of the Stretch Reflex

Increased activity in the fusimotor system (gamma motor neurons), leads to an increase in the sensitivity of the stretch reflex.

Skeletal Muscle Contraction

Stimulation of Type 1a sensory nerve endings can cause skeletal muscle contraction.
Stimulation of the alpha motor neurons in the spinal cord also causes skeletal muscle contraction.

Dynamic Response of the Muscle Spindle Receptor

The dynamic response of the muscle spindle receptor is an increase in activity of the receptor that is proportional to the rate of change in length of the muscle fiber.

Type II Sensory Fibers

Stimulation of Type II sensory fibers innervating a muscle spindle leads to activation of an alpha motor neuron connected to the muscle containing the spindle receptor.

Primary Function of the Golgi Tendon Organ

The Golgi tendon organ senses muscle tension and helps equalize the contractile force exerted by groups of muscle fibers in a muscle.

Activation of Type 1b Sensory Neuron

Activation of a type 1b sensory neuron inhibits muscle contraction in the muscle fiber associated with the neuron.

Muscle Contraction Causes

Stimulation of alpha motor neurons can cause muscle contraction.
Stimulation of gamma motor neurons can also cause muscle contraction.
Stimulation of Type 1a sensory endings from a nuclear bag fiber in the muscle spindle can trigger muscle contraction.

Type 1a Afferents

Type 1a afferents innervate the nuclear chain fibers, the static nuclear bag fibers, and the dynamic nuclear bag fibers of the muscle spindle.

Altering Stretch Reflex Sensitivity

Activity of the pontine reticular nuclei alters the sensitivity of the stretch reflex.

Patellar Tendon Reflex Activation

The patellar tendon reflex is activated by the stimulation of Type 1a sensory fibers.

Muscle Contraction under Basal Conditions

Type 1a sensory fibers can lead to muscle contraction under basal conditions.

Muscle Spindle Function

Muscle spindles sense the length of a muscle.

Flexor Withdrawal Reflex

The flexor withdrawal reflex is a polysynaptic reflex involving nociceptors as sensory receptors.

Anterior Motor Neuron Innervation Targets

Alpha motor neurons innervate extrafusal muscle fibers.
Gamma motor neurons innervate intrafusal muscle fibers.

Golgi Tendon Organ Reflex Arc

The Golgi tendon organ has a disynaptic reflex arc that leads to relaxation of the muscle.

Renshaw Cells

Renshaw cells release glycine.
Renshaw cells are inhibitory under normal physiological conditions.

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Description

Test your knowledge about muscle physiology with this quiz focusing on sensory receptors like Golgi tendon organs and muscle spindle receptors. Understand their roles in muscle tension, contraction, and the stretch reflex mechanism. Perfect for students studying anatomy and physiology.

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