This is a lab exercise protocol for recording stretch receptor potentials in the dorsal extensor muscle of crayfish. 

The exercises in this experiment will demonstrate:

• the types of muscle receptor organs (MRO): MRO1, which is slow-adapting and discharges for long periods of time with a moderate, constant stretch; MRO2, which is fast-adapting and responds only briefly to sharp, vigorous stretching.
• adaptation, or a decrease in the frequency of firing, in the slow-adapting MRO as the time after the initiation of a constant stretch increases.
• the frequency of firing of MRO1 is directly proportional to the degree of tail flexion or stretching of RM1