An ultrastructural study of the stretch-induced hypertrophy of skeletal muscle.
The teres minor muscle of the adult chicken was studied ultrastructurally following tonic stretch-induced hypertrophy. The contralateral control muscle fibres showed compact myofibrils and proliferation of normal Z-bands. Myofibrils of the hypertrophied muscle however, showed Z-band alterations as Z-band expansions and Z-band streaming. Thus Z-band is a highly responsive structure to tonic stretch. Since a number of neuromuscular conditions display Z-band anomalies, the latter occurring in response to a variety of metabolic and physiologic stimuli, including tonic stretch as shown here, represents a non-specific phenomenon.
D000818:Animals; D002645:Chickens; D005260:Female; D006984:Hypertrophy / Q000209:etiology; D008854:Microscopy, Electron; D009132:Muscles / Q000502:physiology / Q000648:ultrastructure*; D012518:Sarcomeres / Q000648:ultrastructure