Quantitative changes in the frog muscle spindle with passive stretch.
D000818:Animals; D001001:Anura; D002467:Cell Nucleus; D008722:Methods; D008854:Microscopy, Electron; D009119:Muscle Contraction; D009470:Muscle Spindles / Q000166:cytology* / Q000502:physiology; D009132:Muscles / Q000166:cytology / Q000502:physiology*; D009210:Myofibrils; D009411:Nerve Endings / Q000166:cytology; D009474:Neurons; D010507:Periodicity; D011894:Rana pipiens