Electron-dense material within sarcoplasmic reticulum apposed to transverse tubules and to the sarcolemma in dog papillary muscle fibers.
D000818:Animals; D002462:Cell Membrane; D004285:Dogs; D008854:Microscopy, Electron; D009206:Myocardium / Q000166:cytology*; D009210:Myofibrils / Q000166:cytology*; D010210:Papillary Muscles / Q000166:cytology