Which receptors detect temperature and chemical changes in muscle tissue?

• A. Small-diameter nerve fibers
• B. Large-diameter nerve fibers
• C. Mechanoreceptors
• D. Muscle spindle receptors

Answer: (A)

Small-diameter afferent fibers carry temperature and chemical signals from muscle tissue. These thin fibers, including A-delta and C fibers, convey thermoreception and chemoreception, such as changes in pH, CO2, and metabolite buildup during activity. Mechanoreceptors, by contrast, respond to mechanical changes like stretch or force and are carried by larger-diameter fibers, while muscle spindle receptors are specific proprioceptors that track muscle length and movement. So the receptors detecting temperature and chemical changes in muscle are the ones tied to small-diameter nerve fibers.