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.
What is an example of stretch reflex stimulated by passive muscle movement?
Patellar reflex- It is a deep tendon reflex. It is a sudden kicking movement of the lower leg in response to tap on the patellar tendon. Tapping of the patellar ligament stimulates the muscle spindles in the quadriceps. It is a passive muscle movement.
What are the two categories of a stretch reflex?
Stretch Reflexes
The stretch reflex consists of a monosynaptic response from the direct connection between Ia afferents and motor neurons, that may be followed by polysynaptic reflex activity.
What happens when the stretch reflex is activated?
When the stretch reflex is activated the impulse is sent from the stretched muscle spindle and the motor neuron is split so that the signal to contract can be sent to the stretched muscle, while a signal to relax can be sent to the antagonist muscles.
What is passive stretching?
Passive stretching is a type of stretching in which you stay in one position for a set time. You're able to relax your body while a partner, accessory, or prop intensifies the stretch by putting external pressure on your body. You can also use the floor or a wall.
Which reflex is associated with muscle stretching?
Myotatic reflex
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.
What happens in an antagonist muscle when the stretch reflex is initiated?
The antagonistic muscle is inhibited and the agonist muscle contracts i.e. in the knee jerk reflex the quadriceps contract and the hamstrings relax.
Frequently Asked Questions
What is the spinal stretch reflex?
The stretch reflex is a monosynaptic reflex that originates in the muscle spindles with any stimulus (not just stretch) and travels through an afferent pathway to the spinal cord (SC) where it synapses with the corresponding alpha motor neuron and contracts the muscle fibers where it is has produced the stimulus.
When tapping the patellar tendon causes a muscle to stretch?
When the physician taps the patellar tendon with a hammer, this action causes the knee extensor muscle to stretch abruptly. This stretch activates the myotatic reflex, causing an extension of the lower leg. (Because the physician taps the tendon, this reflex is also referred to as the deep tendon reflex.
What is the patellar knee jerk reaction as it relates to muscle spindles?
The patellar tendon reflex is elicited by stimulating the patella tendon, classically by a reflex hammer, located inferior to the patella. The stimulation stretches muscle spindles located in the quadriceps muscles, and this muscle spindle stretch excites afferent sensory neurons that innervate the muscle spindles.
Which of the following is responsible for activating the stretch reflex?
The stretch reflex is activated (or caused) by a stretch in the muscle spindle. When the stretch impulse is received a rapid sequence of events follows. The motor neuron is activated and the stretched muscles, and its supporting muscles, are contracted while its antagonist muscles are inhibited (relaxed).
FAQ
- What leads to the stretch reflex?
- Once a stretch reflex occurs, the impulse is sent from the stretched muscle spindle, to the alpha motor neuron. The alpha motor neuron is split. Hence it is able to cause contraction in the synergistic group, and relaxation in the antagonistic group.
- What type of reflex is a stretch reflex?
- The stretch reflex can be a monosynaptic reflex which provides automatic regulation of skeletal muscle length, whereby the signal entering the spinal cord arises from a change in muscle length or velocity.
- What is 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.
- Which reflexes are Monosynaptic?
- When the arc consists of one sensory and motor neuron, it is referred to as a monosynaptic reflex (with 'monosynaptic' referring to one synapse). Monosynaptic reflexes include, for example, the biceps and triceps reflexes, and patellar stretch reflex or knee jerk (see figure below).
Which spinal reflex is invoked in agonist-contract stretching?
| What is the effect when a muscle spindle is activated? | The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, for example, by activating motor neurons via the stretch reflex to resist muscle stretch. |
| Do muscle spindles cause contraction? | Stimulation of muscle spindles elicits a contraction in the stretched muscle (myotatic reflex, i.e. stretch reflex) and at the same time inhibits action potentials to antagonistic muscles. The muscle spindles also participate in regulating the muscle tone. |
| What happens when the muscle spindles are suddenly stretched? | 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 happens to muscle fibers when you stretch? | The stretching of a muscle fiber begins with the sarcomere, the basic unit of contraction in the muscle fiber. As the sarcomere contracts, the area of overlap between the thick and thin myofilaments increases. As it stretches, this area of overlap decreases, allowing the muscle fiber to elongate. |
- What is the muscle spindle and stretch reflex?
- When muscles lengthen, the spindles are stretched. This stretch activates the muscle spindle which in turn sends an impulse to the spinal cord. This impulse results in the activation of more motor neurons at spinal level that send an impulse back to the muscle.
- Which spinal reflex is invoked in agonist-contract stretching
- By J Dolbow · 2022 · Cited by 3 — The myotatic reflex is monosynaptic, induced by the sudden passive muscle belly fiber stretch, and produces a muscle contraction in the agonist muscle or
- Which type of stretching is most likely to elicit a stretch reflex?
- The muscle stretch reflexes readily elicited in term newborns are the pectoralis, biceps, brachioradialis, knee, and ankle jerks. I have considerable difficulty