Final answer:
The muscle spindle detects excessive stretch within the muscle, the given statement is true because muscle spindles are proprioceptive stretch receptors that provide sensory feedback to the central nervous system to coordinate muscle contraction and maintain muscle length.
Step-by-step explanation:
Muscle spindles are proprioceptive stretch receptors that are located within muscles. They detect the amount of stretch or lengthening that occurs in the muscle and provide important sensory feedback to the central nervous system.
When a muscle is stretched, the muscle spindle is activated and sends sensory signals to the spinal cord. These signals are then relayed to the brain, which processes the information and coordinates appropriate muscle contraction and relaxation to maintain muscle length and prevent injury.
For example, if you pull on your bicep muscle, the muscle spindle in that muscle will detect the stretch and send signals to the brain. The brain will then initiate muscle contraction to oppose the stretching force and bring the muscle back to its optimal length. This protects the muscle from excessive stretching and potential damage. Therefore the statement "The muscle spindle detects excessive stretch within the muscle" is true.