Structure and Function of Membrane Systems of Skeletal Muscle Cells

The sections in this article are: 1 Structural Components of Skeletal Muscle Fibers 1.1 Sarcomeres, Striations, and Fibrils 1.2 Membranes 2 Physiological Correlates 2.1 Local Activation Experiments 2.2 Comparison of Slow-Acting and Fast-Acting Muscle Fibers 2.3 Relation of Total Surface Area to Fiber Capacitance 2.4 Glycerol-Shock Experiments 3 Microscopic Methods in Study of Cellular Membrane Structure 3.1 Scanning Electron Microscopy 3.2 High-Voltage Electron Microscopy of Thick Sections 3.3 Freeze-Fracture Electron Microscopy 4 T System 4.1 Definition, Development, and Function 4.2 T-Tubule Networks 4.3 T-Tubule Shapes 5 Sarcoplasmic Reticulum 5.1 Definition, Development, and Function 5.2 Structural Relationship to Myofibrils and Striations 5.3 Form of Sarcoplasmic Reticulum 5.4 Content of Sarcoplasmic Reticulum 5.5 Calcium Movements 6 Intrinsic Membrane Proteins 6.1 Sarcoplasmic Reticulum 6.2 T Tubules 7 Comparative Structure of Sarcoplasmic Reticulum and T System 7.1 Fibers With One Small Dimension and No T System 7.2 Fibers With Low Speed and Small Quantity of Membranes 7.3 Fibers With High Speed and Large Quantity of Membranes 7.4 Variation in Speed and Quantity of Membranes in Mammalian Fibers 7.5 Invertebrate Fibers 8 T-System-Sarcoplasmic Reticulum Couplings 8.1 Basic Form 8.2 Structural Details 8.3 Role of T-Tubular Calcium Current in Excitation- Contraction Coupling 8.4 Functional Mechanism of Coupling Between T Tubules and Sarcoplasmic Reticulum 9 Special Geometry of T System 9.1 Longitudinal T Tubules 9.2 Helicoids 9.3 Structural and Functional Implications