scholarly journals THE SARCOPLASMIC RETICULUM OF STRIATED MUSCLE OF A CYCLOPOID COPEPOD

1963 ◽  
Vol 17 (3) ◽  
pp. 629-640 ◽  
Author(s):  
Wolf H. Fahrenbach
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Sarcoplasmic Reticulum ◽  
Striated Muscle ◽  
Cyclopoid Copepod ◽  
Dense Network ◽  
Abdominal Musculature ◽  
Contraction Speed ◽  
Tubular System ◽  
Fast Acting

The fine structure of the abdominal musculature of the copepod Macrocyclops albidus was investigated by electron microscopy. Tubules penetrate into the muscle fibers from the sarcolemma, continuity between the wall of the tubules and the sarcolemma being clear. A dense network of tubules envelops the myofibrils, its interstices being occupied by cisternal elements. At the Z lines the tubules traverse the interior of myofibrils, giving off branches which course longitudinally within the substance of the myofibrils. These branches are also accompanied by elongate, non-intercommunicating cisternae. Comparison of this fast acting copepod muscle with other vertebrate and invertebrate muscles indicates that the complexity of the tubular system is a function of the myofibrillar geometry, whereas the degree of development of the cisternal system is related to the contraction speed of the muscle.

High Voltage Electron Microscopy of Muscle

1969 ◽  
Vol 27 ◽  
pp. 96-97
Author(s):  
Robert V. Rice ◽  
J. S. Lally
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
High Voltage ◽  
Striated Muscle ◽  
High Voltage Electron Microscopy ◽  
Thin Sections ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Cell Biol ◽  
Adjacent Structures

Several structures have been proposed to account for the appearance of Z and M-lines seen in thin sections of striated muscle. The high penetrating power of 800,000 to 1,000,000 volt electrons coupled with stereology offers a unique opportunity to resolve the complicated fine structure of Z and M-lines. In addition use has been made of the recently developed extraction and reconstitution of Z and M-lines (Stromer, Hartshorne, Mueller, and Rice, J. Cell Biol., 40, 167, 1969). Removal of portions of these structures helps to eliminate confusion due to adjacent structures.

The Ultrastructure of the White Striated Myotomal Muscle of the Cod, Gadus morhua

1967 ◽  
Vol 24 (12) ◽  
pp. 2549-2553 ◽  
Author(s):  
C. M. Bishop ◽  
P. H. Odense
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Cross Section ◽  
Actin Filaments ◽  
Gadus Morhua ◽  
Striated Muscle ◽  
Fish Muscle ◽  
Transverse Tubular System ◽  
Tubular System ◽  
Myotomal Muscle

The structure of the white skeletal muscle of the cod (Gadus morhua) is described. The peripheral fibrils are ribbon-like and rectangular in cross section with the long axis normal to the sarcolemma. The inner fibrils are mainly polygonal in cross section. Most of the mitochondria and nuclei are peripheral to the fibrils and next to the sarcolemma. The arrangement of the contractile proteins is typical for striated muscle, and the sarcoplasmic reticulum and transverse tubular system are similar to those in other white skeletal fish muscle. A distinct N-band is apparent with indications of branching and reorientation of the actin filaments. Mitochondria are often closely associated with the Z line.

scholarly journals OBLIQUELY STRIATED MUSCLE

1968 ◽  
Vol 36 (1) ◽  
pp. 245-259 ◽  
Author(s):  
Jack Rosenbluth
Keyword(s):  
Electron Microscopy ◽  
Sarcoplasmic Reticulum ◽  
Connective Tissue ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Body Muscle ◽  
Dense Bodies ◽  
Thick Filaments ◽  
Predominant Type ◽  
Physiological Differences

Body muscle cells of the bloodworm Glycera, a polychaete annelid, were studied by electron microscopy and compared with muscle cells of the more slowly acting nematode Ascaris, which have been described previously. Both muscles are obliquely striated. The predominant type of bloodworm fiber is characterized by a prominent transversely oriented sarcoplasmic reticulum with numerous dyads at the surface of each cell. Thick myofilaments are ∼3 µ long and overlap along ∼60% of their length in extended fibers and ∼80% in shortened fibers. There is virtually no endomysium and very little intracellular skeleton, and the cells are attached by desmosomes to one another rather than to connective tissue. Dense bodies are absent from the fibers and in their place are Z lines, which are truly linear rather than planar. Scattered among the predominant fibers are others, less orderly in arrangement, in which the SR is much less prominent and in which the thick filaments are thicker and longer and overlap to an even smaller degree. It is suggested that physiological differences between bloodworm and Ascaris muscles derive from differences in the proportion of series to parallel linkages between the contractile elements, differences in the amount and disposition of the SR, and differences in the impedance to shear within the myofibrils.

scholarly journals THE SARCOPLASMIC RETICULUM AND ITS ASSOCIATION WITH THE T SYSTEM IN AN INSECT

1967 ◽  
Vol 32 (3) ◽  
pp. 535-545 ◽  
Author(s):  
Martin Hagopian ◽  
David Spiro
Keyword(s):  
Fine Structure ◽  
Sarcoplasmic Reticulum ◽  
Cell Surface ◽  
Osmium Tetroxide ◽  
Surface Membrane ◽  
Transverse Tubular System ◽  
Leucophaea Maderae ◽  
Tubular System ◽  
Femoral Muscle ◽  
T System

The fine structure of the sarcoplasmic reticulum and the transverse tubular system of the femoral muscle of the cockroach, Leucophaea maderae, was studied after prefixation in glutaraldehyde, postfixation in osmium tetroxide, and embedding in Epon. The sarcoplasmic reticulum in this muscle reveals features not previously reported. The sarcoplasmic reticulum is abundant, consisting mainly of a fenestrated envelope which surrounds each myofibril at all levels in the sarcomere. This sarcoplasmic reticulum envelope is continuous transversally as well as longitudinally along the myofibrils. Dyadic junctions are formed by a single T system element which contacts the unfenestrated sarcoplasmic reticulum of adjacent myofibrils in an alternating manner at the ends of the A band. At the dyads, regularly spaced thickenings of the sarcoplasmic reticulum membranes bordering the dyadic spaces are noted. These thickenings, however, do not contact the T tubule membrane. Typical dyadic contacts also are seen between the cell surface membrane and sarcoplasmic reticulum. Z line-like material is seen in contact with the membranes of the cell surface and longitudinal branches of the T systems.

Ca2+ and activation mechanisms in skeletal muscle

1991 ◽  
Vol 24 (1) ◽  
pp. 1-73 ◽  
Author(s):  
Christopher C. Ashley ◽  
Ian P. Mulligan ◽  
Trevor J. Lea
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Electrical Activity ◽  
Calcium Ions ◽  
Crucial Role ◽  
Striated Muscle ◽  
Surface Membrane ◽  
Muscle Fibres ◽  
Tubular System ◽  
Activation Mechanisms

It has been known for a number of years that calcium ions play a crucial role in excitation-contraction (e-c) coupling (Sandow, 1952). The majority of the calcium required for this process is derived, at least in vertebrate striated muscle fibres, from discrete intracellular stores located at sites within the cell: the terminal cysternae (tc)/junctional SR of the sarcoplasmic reticulum (SR) (Fig. 1 a). These storage sites not only form a compartment that is distinct from the sarcoplasm of the fibre, but they are also closely associated with the contractile elements, the myofibrils. The SR release sites are activated following the spread of electrical activity (Huxley and Taylor, 1958) along the transverse (T) tubular system (Eisenberg and Gage, 1967; Adrian et al. 1969a, b; Peachey, 1973) from the surface membrane (Bm).

scholarly journals STRUCTURE OF THE LONGITUDINAL BODY MUSCLES OF AMPHIOXUS

1961 ◽  
Vol 10 (4) ◽  
pp. 159-176 ◽  
Author(s):  
Lee D. Peachey
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Sarcoplasmic Reticulum ◽  
Internal Structure ◽  
Striated Muscle ◽  
Light And Electron Microscopy ◽  
Maximum Distance ◽  
Hexagonal Array ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling

The structure of the longitudinal body muscles of Branchiostoma caribaeum has been studied by light and electron microscopy. These muscles are shown to be composed of fibers in the form of flat lamellae about 0.8µ in thickness, more than 100 µ wide, and reaching in length from one intermuscular septum to the next, a distance of about 0.6 mm. Each flat fiber is covered by a plasma membrane and contains a single myofibril consisting of myofilaments packed in the interdigitating hexagonal array characteristic of vertebrate striated muscle. Little or no sarcoplasmic reticulum is present. Mitochondria are found infrequently and have a tubular internal structure. These morphological observations are discussed in relation to a proposed hypothesis of excitation-contraction coupling. It is pointed out that the maximum distance from surface to myofilament in these muscles is about 0.5 µ and that diffusion of an "activating" substance over this distance would essentially be complete in less than 0.5 msec. after its release from the plasma membrane. It is concluded that the flat form of amphioxus muscle substitutes for the specialized mechanisms of excitation-contraction coupling thought possibly to involve the sarcoplasmic reticulum in higher vertebrate muscles.

scholarly journals STUDIES ON THE ENDOPLASMIC RETICULUM

1957 ◽  
Vol 3 (2) ◽  
pp. 269-300 ◽  
Author(s):  
Keith R. Porter ◽  
George E. Palade
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Muscle Contraction ◽  
Striated Muscle ◽  
Cell Types ◽  
Entire System ◽  
Structural Components ◽  
Reticular Structure ◽  
Vacuolar System

Several types of striated muscle have been examined by the technics of electron microscopy and the findings in myotome fibers of Amblystoma larvae, the sartorius, and cardiac muscle of the rat are reported on in some detail. Particular attention has been given to structural components of the interfibrillar sarcoplasm and most especially to a finely divided, vacuolar system known as the sarcoplasmic reticulum. This consists of membrane-limited vesicles, tubules, and cisternae associated in a continuous reticular structure which forms lace-like sleeves around the myofibrils. It shows a definable organization which repeats with each sarcomere of the fiber so that the entire system is segmented in phase with the striations of the associated myofibrils. Details of these repetitive patterns are presented diagrammatically in Text-figs. 1, 2, and 3 on pages 279, 283, and 288 respectively. The system is continuous across the fiber at the H band level and largely discontinuous longitudinally because of interruptions in the structure at the I and Z band levels. The structure of the system relates it to the endoplasmic reticulum of other cell types. The precise morphological relation of the reticulum to the myofibrils, with specializations opposite the different bands, prompts the supposition that the system is functionally important in muscle contraction. In this regard it is proposed that the membrane limiting the system is polarized like the sarcolemma and that the corresponding potential difference is utilized in the intracellular distribution of the excitatory impulse.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Fibroblasts During Hypertrophic Scar Formation and Resolution

1973 ◽  
Vol 31 ◽  
pp. 428-429
Author(s):  
C. W. Kischer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Proliferation ◽  
Fine Structure ◽  
Metabolic Activity ◽  
Hypertrophic Scar ◽  
Normal Skin ◽  
Ground Substance ◽  
Hypertrophic Scars ◽  
Scanning Electron

The morphology of the fibroblasts changes markedly as the healing period from burn wounds progresses, through development of the hypertrophic scar, to resolution of the scar by a self-limiting process of maturation or therapeutic resolution. In addition, hypertrophic scars contain an increased cell proliferation largely made up of fibroblasts. This tremendous population of fibroblasts seems congruous with the abundance of collagen and ground substance. The fine structure of these cells should reflect some aspects of the metabolic activity necessary for production of the scar, and might presage the stage of maturation.A comparison of the fine structure of the fibroblasts from normal skin, different scar types, and granulation tissue has been made by transmission (TEM) and scanning electron microscopy (SEM).

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