What is the Myotatic stretch reflex

The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching. When a muscle is stretched, the stretch reflex regulates the length of the muscle automatically by increasing its contractility as long as the stretch is within the physiological limits.

When does the myotatic reflex occur?

When a muscle spindle is stretched an impulse is immediately sent to the spinal cord and a response to contract the muscle is received. Since the impulse only has to go to the spinal cord and back, not all the way to the brain, it is a very quick impulse. It generally occurs within 1-2 milliseconds.

What does Myotatic mean?

Medical Definition of myotatic : relating to or involved in a muscular stretch reflex.

Why is myotatic reflex important?

The purpose of the myotatic reflex is to resist changes in muscle length. This is useful when one is trying to maintain the position of a limb during purposeful work or in maintaining posture, but it is counter-productive during purposeful movements when the muscles must contract while their antagonist member relaxes.

What is the myotatic reflex quizlet?

Myotatic Reflex. aka “the stretch reflex” or “the Deep Tendon reflex” • Definition: Tonic contraction of the muscles in response to a. stretching force, due to stimulation of muscle proprioceptors. • It is the basis of the knee jerk response that is routinely tested in the neurological examination.

How the myotatic reflex is activated by hitting the Achilles tendon?

Alpha motor neurons in the spinal cord cause a brief, rapid contraction of the quadriceps femoris, which causes the leg to extend. Tapping the Achilles tendon behind the ankle and just above the heel activates plantar flexion of the foot. This reflex response is like walking tip-toed or standing on your toes.

What does an absent myotatic reflex mean?

Absence (0) of a myotatic reflex indicates a lesion of the sensory or motor component of the reflex arc—an LMN or segmental sign (see Table 1-3).

What is the muscle response during the reverse myotatic reflex?

When the tension is extreme, the inhibition can be so great it overcomes the excitatory effects on the muscle’s alpha motoneurons causing the muscle to suddenly relax. This reflex is also called the inverse myotatic reflex, because it is the inverse of the stretch reflex.

What is the inverse myotatic reflex?

The Inverse Myotatic Reflex Involves Sensors of Muscle Force in the Tendon. Stretch receptors called Golgi tendon organs are found within the collagen fibers of tendons and within joint capsules. … In this way, high force development that could injure muscles can be prevented by relaxation of the muscle.

What is the receptors involved in a myotatic reflex arc?

A receptor – muscle spindle. An afferent fibre – muscle spindle afferent. An integration centre – lamina IX of spinal cord. An efferent fibre – α-motoneurones.

Article first time published on

How do you overcome Myotatic reflexes?

1. Create a strong stretch.
2. Strongly contract the muscle that is stretching and hold for 5 to 30 seconds.
3. Stop contracting stretching muscle.
4. You should feel release in stretching muscle; if so move deeper into pose.
5. Repeat.

How many neurons and spinal cord synapses are involved in the Myotatic stretch reflex?

The myotatic or stretch reflexes are basic to the regulation of posture and movement. The reflex arc is a simple two-neuron (monosynaptic) pathway. The sensory neuron has a receptor in the muscle spindle and its cell body in the spinal ganglion.

How does the patellar reflex work?

knee-jerk reflex, also called patellar reflex, sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon, which lies just below the kneecap. … In reaction these muscles contract, and the contraction tends to straighten the leg in a kicking motion.

How might this patellar reflex help maintain upright posture?

Stretch reflexes are very important in maintaining your upright posture in humans. … Tapping the patellar tendon stretches the quadriceps muscle and causes the sensory receptor of the muscle, called a spindle fiber, to send a signal along the afferent neuron to the spinal cord.

What is the effect of mental distraction on the patellar reflex?

Mental distraction plays no part on the reflex. This caused the patellar reflex to be less vigorous immediately following exercise.

What effect would the Jendrassik maneuver have on the myotatic reflex?

Discussion: 1) What effect does the Jendrassik maneuver have on the myotatic reflex? A larger reflex response (angle) is usually observed when an individual is distracted by this maneuver.

What is the purpose of the stretch reflex quizlet?

The stretch reflex (myotatic reflex) is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length. When a muscle lengthens, the muscle spindle is stretched and its nerve activity increases.

What is the Achilles reflex response?

The Achilles reflex is a monosynaptic stretch reflex similar to the patellar reflex. In the Achilles reflex, the hammer taps the Achilles tendon while the foot is dorsiflexed, and the foot, in response, should jerk toward the plantar surface. The Achilles reflex originates in the S1 and S2 nerve roots.

What is the gamma loop?

The gamma loop (also referred to as the alpha-gamma loop) is a feedback loop in our nervous system that regulates the level of tension in our muscles. … In future posts I’ll talk about two closely related topics: how the stretch reflex (myotatic reflex) works, and how we build up residual muscle tension.

What is the stimulus for the Golgi tendon organ?

The contraction of these fibres, exerting strain on the collagenous bundle and causing deformation of sensory terminals, is the adequate stimulus of the tendon organ. For this stimulus, the tendon organ has a very low threshold, so that a single fibre twitch can elicit a discharge from the receptor.

What is Intrafusal muscle fibers?

Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors). They detect the amount and rate of change in length of a muscle. They constitute the muscle spindle, and are innervated by both sensory (afferent) and motor (efferent) fibers.

What type of reflex is the patellar stretch reflex?

The knee-jerk reflex, also known as the patellar reflex, is a simple reflex that causes the contraction of the quadriceps muscle when the patellar tendon is stretched.

Is clonus a spasticity?

Spasticity and clonus result from an upper motor neuron lesion that disinhibits the tendon stretch reflex; however, they are differentiated in the fact that spasticity results in a velocity dependent tightness of muscle whereas clonus results in uncontrollable jerks of the muscle.

What is gamma motor neuron?

A gamma motor neuron (γ motor neuron), also called gamma motoneuron, or fusimotor neuron, is a type of lower motor neuron that takes part in the process of muscle contraction, and represents about 30% of (Aγ) fibers going to the muscle.

Which muscles are the effectors in a patellar reflex?

What is the patellar reflex? A monosynaptic reflex extension of the leg resulting from a sharp tap on the patellar tendon. It helps maintain and upright position. It’s effector muscles are located in the quadriceps femoris.

What is spiral cord?

The spinal cord is a long bundle of nerves and cells that extends from the lower portion of the brain to the lower back. It carries signals between the brain and the rest of the body.

Which neurons are the main afferents involved in the stretch reflex circuit?

Figure 28.6. Basic circuitry underlying the knee-jerk stretch reflex. Ia spindle afferents from the quadriceps muscle make monosynaptic, excitatory connections on α-motor neurons that innervate the quadriceps.

Which is the true statement about the synapses in the spinal cord in the stretch reflex?

Which is the true statement about the synapses in the spinal cord in the stretch reflex? Interneurons make inhibitory synapses with neurons that prevent contraction of the antagonist muscle.

What causes knee reflex?

The normal knee-jerk reflex involves no input to or from the brain. The normal knee-jerk or, “patellar jerk,” reflex is elicited when the knee is tapped below the knee cap (patella). Sensors that detect stretching of the tendon of this area send electrical impulses back to the spinal cord.