What response does the stretch reflex initiate in a muscle?
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 are stretch reflexes?
I Definition. Muscle stretch reflexes are involuntary contractions of muscles induced by a brisk stretch of the muscle. Muscle stretch reflexes are usually named after the muscle being tested (Table 63.1), the one notable exception being the Achilles or ankle jerk.
Where are reflexes initiated?
spinal cord
Most reflex arcs involve only three neurons. The stimulus, such as a needle stick, stimulates the pain receptors of the skin, which initiate an impulse in a sensory neuron. This travels to the spinal cord where it passes, by means of a synapse, to a connecting neuron called the relay neuron situated in the spinal cord.
Who Discovered stretch reflex?
The stretch reflex and the contributions of C David Marsden. Annals of Indian Academy of Neurology, 20(1): 1-4.
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).
What receptors initiate the inverse stretch 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.
What are the functions 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.
How is reflex generated?
Reflexes, Spinal Cord and Blink Reflexes are involuntary activity arising from an afferent input and a subsequent efferent response. These can be proprioceptive arising from receptors within muscles, tendons, and joints or exteroceptive arising from skin and subcutaneous tissues.
Why do we have a stretch reflex?
The stretch reflex is designed as a protective mechanism, to prevent strain and tear injuries to the muscles and tendons. When the muscle spindle is excited an impulse is immediately received to contract the muscle, thereby protecting it from being pulled forcefully or stretched beyond a normal range of motion.
What is true about stretch reflex quizlet?
What is an example of a stretch reflex?
Another example of the stretch reflex is the knee-jerk test performed by physicians. When the patellar tendon is tapped with a small hammer, or other device, it causes a slight stretch in the tendon, and consequently the quadriceps muscles.
What is the definition of stretch reflex?
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. A sudden stretch, such as tapping the Achilles ‘ tendon, causes a reflex contraction in the muscle as the spindles sense the stretch and send an action potential to the motor neurons which then cause the muscle to contract; this particular reflex causes a contraction in the soleus-gastrocnemius group of muscles.
What are the steps of the reflex arc?
A simple reflex arc has five steps: A stimulus: An outside force that does something. Afferent, or sensory neurons, carry the impulse to the spinal cord. Interneurons in the spinal cord integrate and plan a response. Efferent, or motor neurons, carry out the response. The effector response is the action carried out.
What nerves are involved in patellar reflex?
The patellar tendon reflex tests the function of the femoral nerve and spinal cord segements L2-L4. The patellar reflex is a clinical and classic example of the monosynaptic reflex arc. There is no interneuron . Instead the bipolar sensory neuron synapses directly on a motor neuron in the spinal cord.
