scholarly journals The Fine Structure of the Interrelationship of Cells in the Human Epidermis

1958 ◽  
Vol 4 (5) ◽  
pp. 529-538 ◽  
Author(s):  
George F. Obland
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Basement Membrane ◽  
Surface Area ◽  
Epidermal Cell ◽  
Functional Significance ◽  
Intercellular Bridges ◽  
Human Forearm ◽  
Extensive Surface

In the present investigation an analysis has been made of the fine structure of the interrelationships of cells in human forearm epidermis by means of the electron microscope. The "intercellular bridges," here called attachment zones, are more complex than has previously been recognized. It is shown that dense oval thickenings, called attachment plaques, appear in apposed areas of adjacent epidermal cell membranes. The tonofibrils terminate at the internal face of the attachment plaque and do not traverse the 300 A distance between apposed plaques. Seven intervening layers of unidentified substance occupy the space between attachment plaques. The attachment zones appear in all of the classical histological layers of the epidermis. The portions of epidermal cell membrane not involved in intercellular attachments have extensive surface area resulting from plication of the membrane, and its further modification to form microvilli. The possible functional significance of these observations is discussed. Prior observations concerning the basement membrane of epidermis are confirmed. Identification of epidermal melanocytes is achieved, the finer morphology of their dendritic processes is described, and their relationship to epidermal cells is discussed.

An Electron Microscope study of a Small Free-living Amoeba (Hartmanella astronyxis)

1959 ◽  
Vol s3-100 (49) ◽  
pp. 13-15
Author(s):  
K. DEUTSCH ◽  
M. M. SWANN
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Layered Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Honeycomb Structure ◽  
Free Living ◽  
Free Living Amoeba

The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.

Studies on the Receptors in the Cerebral Vesicle of the Ascidian Tadpole, I. The Otolith

1962 ◽  
Vol s3-103 (63) ◽  
pp. 393-398
Author(s):  
P. N. DILLY
Keyword(s):  
Complex System ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Basement Membrane ◽  
Cerebral Ganglion ◽  
Entire Life ◽  
Foot Process ◽  
Gravity Receptor ◽  
Ventral Wall ◽  
Cerebral Vesicle

Electron microscope observations of the gravity receptor of the tadpole larva of Ciona intestinalis show that the otolith is unicellular. The nucleus of the otolith persists for the entire life of the tadpole. The pigment mass of the otolith is intracellular, and it appears to be built up by fusion of granules. The otolith cell has a free part within the cavity of the cerebral vesicle, and a foot part which is contained within a mound of cells on the ventral wall of the cerebral vesicle. The junction between these two parts is probably the transducer region. The transducer region is a complex system of folded cell membrane. Distortion of this system during rotation of the tadpole while swimming probably evokes changes in the neurones which surround the foot process of the otolith cell. One of these neurones is connected to the cerebral ganglion by a process which may be an axon. Fibrils extend from the transducer region of the otolith cell to the basement membrane, and probably serve to resist distortion of the transducer region. The foot process of the otolith cell is connected to the surrounding cells by specializations of the cell membrane similar to attachment plaques. The observations suggest that the otolith has been evolved from a cilium.

Differentiation of Neurosensory Cells in Hydra

1969 ◽  
Vol 5 (3) ◽  
pp. 699-726
Author(s):  
LOWELL E. DAVIS
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Basal Body ◽  
Neurosecretory Cells ◽  
Nerve Cells ◽  
Granular Endoplasmic Reticulum ◽  
Structural Variations ◽  
Intercellular Bridges ◽  
Undifferentiated Cells

The differentiation of neurosensory cells in Hydra has been studied at the level of the electron microscope. These cells arise from interstitial cells (undifferentiated cells) and not from pre-existing nerve cells. Furthermore, there is no evidence to suggest that neurosensory cells represent a stage in the development of other nerve cells, i.e. ganglionic and neurosecretory cells. Major cytoplasmic changes in fine structure during differentiation include development of a cilium and associated structures (basal body, basal plate, rootlets), development of microtubules and at least two neurites, increase in Golgi lamellae and formation of dense droplets typical of neurosecretory droplets, structural variations in mitochondria and a decrease in the number of ribosomes. Granular endoplasmic reticulum is characteristically poorly developed in all stages of differentiation, including the mature neurosensory cell. Nuclear and nucleolar changes also occur during differentiation but these are less dramatic than the cytoplasmic events. The possibility of neurosensory cells being bi- or multiciliated and the presence of intercellular bridges between these cells are considered. The function of neurosensory cells is discussed briefly in relation to the function of the cilium and neurosecretory droplets.

scholarly journals The Fine Structure of a Multiterminal Innervation of an Insect Muscle

1959 ◽  
Vol 5 (2) ◽  
pp. 241-244 ◽  
Author(s):  
George A. Edwards
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Electron Microscope ◽  
Basement Membrane ◽  
Neuromuscular Junctions ◽  
Abdominal Muscle ◽  
Membrane Material ◽  
Detailed Structure ◽  
Insect Muscle

The detailed structure of nerve branches, neuromuscular junctions, and muscle fibers of a multiterminal innervation of cockroach abdominal muscle has been studied with the electron microscope. The muscle fiber is of the banded myofibril type; with paired mitochondria and abundant endoplasmic reticulum. The peripheral nerve branches are multiaxonal with large central axon and several small peripheral tunicated axons. Tracheoblasts closely accompany the nerve branches. The multiple neuromuscular junctions show typical axonal vesicles, muscle aposynaptic granules, and close plasma membrane apposition with no interposition of basement membrane material.

Fine structure of an intracerebral epithelial cyst

1974 ◽  
Vol 41 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Nitya R. Ghatak ◽  
Asao Hirano ◽  
Samuel S. Kasoff ◽  
H. M. Zimmerman
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Basement Membrane ◽  
Single Layer ◽  
Cellular Transport ◽  
Epithelial Cyst ◽  
Choroid Plexus Epithelium ◽  
Content Type ◽  
Pinocytotic Vesicles ◽  
Fine Print

✓ The wall of an intracerebral extraventricular cyst was studied with the electron microscope. The lining of the cyst consisted of a single layer of nonciliated, flattened or cuboidal epithelium similar to that in an ependyma. Unlike the ventricular ependyma, the lining cells of the cyst were bordered by a continuous basement membrane abutting on the leptomeninges or on the compressed brain tissue and thus shared some morphological similarities with the choroid plexus epithelium. Although pathogenesis of the cyst remains obscure, the fine structure of the lining cells is suggestive of their neuroepithelial origin. The occurrence of abundant pinocytotic vesicles in these cells further suggests the possibility of cellular transport of fluid to account for the continued expansion of the cyst.

A preliminary study of the fine structure of the oökinete, oöcyst, and sporozoite formation of Leucocytozoon simondi Mathis and Leger

1968 ◽  
Vol 46 (3) ◽  
pp. 303-307 ◽  
Author(s):  
Sherwin S. Desser ◽  
K. A. Wright
Keyword(s):  
Energy Source ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Light Microscope ◽  
Dense Material ◽  
Blue Staining ◽  
Preliminary Study

The major features of the cytology of oökinetes, oöcysts, and sporozoites of Leucocytozoon simondi Mathis and Leger as seen in KMnO4-fîxed midguts of Simulium rugglesi and examined in the electron microscope, are related to their appearance in Giemsa-stained light microscope preparations. Thus, blue-staining regions of oökinete and oöcyst and the posterior, darkly stained region of sporozoites correspond to regions of endoplasmic reticulum; light "vacuole-like" regions correspond to accumulations of dense material which were not membrane enclosed; and minute red-stained spots at the anterior tip of sporozoites correspond to paired organelles. The dense material of oökinetes which, in oöcysts, is segregated into developing sporozoites may function as an energy source for sporozoites. The structure and development of these stages is similar to that of Plasmodium spp. The oöcyst of L. simondi develops extracellularly, enclosed by the basal lamina of the midgut with most of its surface surrounded by the basal cell membrane of midgut epithelial cells. This location of the oöcyst may be important in determining the subsequent pattern of development of this species.

scholarly journals AN ELECTRON MICROSCOPE STUDY OF THE GLOMERULUS IN NEPHROSIS, GLOMERULONEPHRITIS, AND LUPUS ERYTHEMATOSUS

1957 ◽  
Vol 106 (5) ◽  
pp. 649-660 ◽  
Author(s):  
Marilyn G. Farquhar ◽  
Robert L. Vernier ◽  
Robert A. Good
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Basement Membrane ◽  
Lupus Erythematosus ◽  
Structural Changes ◽  
Disease Process ◽  
Variable Degree ◽  
Basement Membrane Thickening ◽  
Endothelial Proliferation ◽  
Pathologic Processes

Renal biopsies from 16 patients with nephrosis, 7 patients with glomerulonephritis, and 3 patients with disseminated lupus erythematosus were studied with the electron microscope. The observations presented indicate that early in the course of each of these diseases alterations occur in the fine structure of the glomeruli which serve to distinguish one disease process from another. In nephrosis, some distortion of the organization of the epithelial foot processes was seen in all patients. These epithelial changes constituted the early, consistent lesion of the disease. There was frequently also a swelling of the endothelium. In glomerulonephritis, pronounced proliferative changes involving the endothelium and to a lesser extent the epithelium, together with the laying down of a basement membrane-like material, represented the predominate pathologic processes. There was also a swelling of both endothelial and epithelial cytoplasm. The epithelial foot processes generally appeared normal. In patients with a clinically "mixed" picture of nephrosis and nephritis, the glomerular changes were likewise "mixed," for various combinations of epithelial, endothelial, and basement membrane abnormalities were present. In disseminated lupus erythematosus, a more or less generalized thickening of the basement membrane proper associated with a variable degree of endothelial proliferation was seen. It is suggested that an accentuation of the process of basement membrane thickening results in the "wire loop" appearance sometimes seen by light microscopy. Although the earliest alterations in glomerular fine structure were characteristic for each of the disease processes, at later stages the changes were not always distinctive. The resulting scarred or "hyalinized" glomeruli, composed of relatively homogeneous, basement membrane-like material, and a few atrophic cells, appeared quite similar. Although the functional implications of the structural changes observed remain obscure at this time, it is believed that insight into mechanisms may stem from such observations.

scholarly journals The Fine Structure of Some Retinal Photoreceptors

1960 ◽  
Vol 7 (1) ◽  
pp. 87-92 ◽  
Author(s):  
M. F. Moody ◽  
J. D. Robertson
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Double Membrane ◽  
Double Structure ◽  
Rods And Cones ◽  
Retinal Photoreceptors ◽  
Bounding Surfaces

An electron microscope study has been made of octopus and amphibian photoreceptors, after fixing with KMnO4 and embedding in araldite. What has previously been seen as a single dense stratum bounding the tubular compartments (octopus) or the double membrane discs (rods and cones), now shows a double structure. We interpret this as showing that these tubules and discs have similar bounding surfaces, which are probably directly related to the cell membrane. This is confirmed by the finding that the tubules and discs are (at least occasionally) continuous with the cell membrane.

scholarly journals THE FINE STRUCTURAL ORGANISATION OF ROUS TUMOUR CELLS

1957 ◽  
Vol 3 (6) ◽  
pp. 851-858 ◽  
Author(s):  
M. A. Epstein
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Tumour Cells ◽  
Thin Sections ◽  
Outer Nuclear Membrane ◽  
Structural Organisation ◽  
Perinuclear Space

The fibroblast-like tumour cells of Rous sarcomata have been studied in thin sections with the electron microscope. A description is given of the fine structure of the cells which includes some features not hitherto recorded. The tightly packed piles of smooth cisternae usually found only in the centrosome region have been observed, in individual Rous cells, in two separate areas of cytoplasm at opposite poles of the nucleus. Continuity between the perinuclear space and the lumen of rough surfaced cisternae of the endoplasmic reticulum has frequently been found; a similar continuity between the cisternae and the exterior of the cell has also been seen. In some cases, the cell membrane has been shown to have an unbroken connection with the outer nuclear membrane through continuity with the limiting membranes of elements of the endoplasmic reticulum. These findings are discussed.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

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