Myotatic reflex is defined as which of the following?

Myotatic reflex is defined as which of the following?

• A. An Excessive Contraction of Muscles
• B. Involuntary Muscular Contractions Obtained by Exciting the Region Corresponding to the Skin
• C. Partial Muscle Contraction
• D. A Reflex Muscle Contraction Caused by Stretching

Answer: (D)

A stretch of the muscle triggers a reflex contraction—the myotatic reflex is the stretch reflex. When a muscle is suddenly lengthened, specialized sensory receptors in the muscle spindle detect that change in length and rate of stretch. The Ia afferent fibers from the spindle convey this signal directly to the spinal cord and synapse on the alpha motor neurons that innervate the same muscle. This monosynaptic circuit causes the muscle to contract quickly to oppose the stretch, helping to maintain posture and muscle tone. This reflex is typically elicited by a quick tap on a tendon, which briefly stretches the muscle and then evokes a brisk contraction as the system resists further stretching. The other options don’t fit because they describe different phenomena: contractions not linked to a stretch sensation, contractions triggered by skin stimulation, or vague partial contractions rather than the specific stretch-evoked, reflexive response.

A stretch of the muscle triggers a reflex contraction—the myotatic reflex is the stretch reflex. When a muscle is suddenly lengthened, specialized sensory receptors in the muscle spindle detect that change in length and rate of stretch. The Ia afferent fibers from the spindle convey this signal directly to the spinal cord and synapse on the alpha motor neurons that innervate the same muscle. This monosynaptic circuit causes the muscle to contract quickly to oppose the stretch, helping to maintain posture and muscle tone.

This reflex is typically elicited by a quick tap on a tendon, which briefly stretches the muscle and then evokes a brisk contraction as the system resists further stretching. The other options don’t fit because they describe different phenomena: contractions not linked to a stretch sensation, contractions triggered by skin stimulation, or vague partial contractions rather than the specific stretch-evoked, reflexive response.