dinesh said:Don't you need ATP for the atpase activity to allow reaccumulation of the caclium in the sarcoplasm.
trudub said:Yes, but that isn't what actually drives the process of relaxation, although it is necessary to maintain relaxation.
trudub said:You are, however, correct to say that it does not cost an ATP to relax the muscle. To relax, you merely need to bind a new ATP. That ATP is not used until the next contraction. So, it does require ATP but to say that it is an energy requiring process might not be exactly accurate.
Hausdaddy24 said:My anatomy textbook actually lists the reuptake of calcium into the sarcoplasmic reticulum (by an active pump) as the very first step of relaxation. without calcium in the sarcoplasm the tropomyosin-troponin complex changes shape and covers myosin binding sites which= relaxation. So yes relaxation is an active process.