What is the stretch reflex response in muscles?

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

Is stretch reflex positive or negative?

The stretch reflex (myotatic reflex), or more accurately “muscle stretch reflex”, is a muscle contraction in response to stretching within the muscle….Clinical significance.

Grade Response Significance
2+ brisk physiologic response normal
3+ very brisk response may or may not be normal
4+ clonus always abnormal

What is the correct order of events of a simple stretch reflex?

Stretch Reflex. When a muscle is stretched (1), muscle spindles (2) send information to the spinal cord (3) where it synapses on motor neuron of the same muscle (4) causing it to contract (5). At the same time, stimulation of an inhibitory interneuron (6) prevents contraction of the antagonistic muscle (7 and 8).

How does stretch reflex affect muscle tone?

Muscle tone is generated by muscle spindles by acting through the stretch reflex. Muscle tone is the constant muscular activity that is necessary as a background to actual movement in order to maintain the basic attitude of the body particularly against the force of gravity (Carpenter, 1984).

What are the 5 elements of the reflex arc?

The pathway can be described as a ‘reflex arc’ which is made up of 5 components:

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

What are the 5 steps of a reflex arc?

So the reflex arc consists of these five steps in order-sensor, sensory neuron, control center, motor neuron, and muscle. These five parts work as a relay team to take information up from the sensor to the spinal cord or brain and back down to the muscles.

What does muscle tone mean?

Muscle tone is the amount of tension (or resistance to movement) in muscles. Our muscle tone helps us to hold our bodies upright when we are sitting and standing. Changes in muscle tone are what enable us to move. Muscle tone also contributes to the control, speed and amount of movement we can achieve.

What are the 3 phases of the stretch shortening cycle?

This pre-stretch, or ‘countermovement’ action is known as the stretch-shortening cycle (SSC) and is comprised of three phases (eccentric, amortization, and concentric) (Figure 1) (3).

What are types of muscle tone?

Muscle tone can be classified as ‘postural’ and ‘phasic’ types. Postural tone is seen in axial muscles where gravity is the most important inciting factor. It results from a steady stretch on the muscles and tendons and manifests as prolonged muscle contraction.

How do you describe normal muscle tone?

Normal tone means that there is the right amount of “tension” inside the muscle at rest, and that the muscle is inherently able to contract on command. Put simply, you can “tell” your muscle to stop and start and it does what you want, when you want, with the appropriate amount of force.

What is muscle stretch reflex?

Muscle Stretch Reflex. A reflex is defined as an involuntary, unlearned, repeatable, automatic reaction to a specific stimulus which does not require input from the brain.

What is the dynamic phase of the stretch reflex?

The static component of the stretch reflex is in place as long as the muscle is stretched. The dynamic phase occurs only when the muscle is stretched e.g. when the tendon is struck with a tendon hammer.

What is the Myotatic reflex?

If we’re involved in sports or physical training, we stretch to warm up, cool down, and during breaks to help us stay loose. Unfortunately, stretching usually doesn’t accomplish much, mainly due to the myotatic reflex, more commonly referred to as the stretch reflex.

How does the stretch reflex travel through the spinal cord?

The stretch reflex skips the brain portion of the trip and follows the simple loop from muscle to spinal cord and back, making it a very rapid sequence. The diagram to the right shows how nerve impulses triggered by the stretch reflex travel between the spinal column and the muscles.