The structure of the gills of the axolotl, Ambystoma mexicanum

1987 ◽  
Vol 45 ◽  
pp. 824-825
Author(s):  
Mohinder S. Jarial
Keyword(s):  
Leydig Cells ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Ambystoma Mexicanum ◽  
Basal Cells ◽  
Granular Cells ◽  
Gill Filaments ◽  
Mitotic Figures ◽  
Apical Membranes

The axolotl is a strictly aquatic salamander in which the larval external gills are retained throughout life. The external gills of the adult axolotl have been studied by light and electron microscopy for ultrastructural evidence of ionic transport. The thin epidermis of the gill filaments and gill stems is composed of 3 cell types: granular cells, the basal cells and a sparce population of intervening Leydig cells. The gill epidermis is devoid of muscles, and no mitotic figures were observed in any of its cells.The granular cells cover the gill surface as a continuous layer (Fig. 1, G) and contain secretory granules of different forms, located apically (Figs.1, 2, SG). Some granules are found intimately associated with the apical membrane while others fuse with it and release their contents onto the external surface (Fig. 3). The apical membranes of the granular cells exhibit microvilli which are covered by a PAS+ fuzzy coat, termed “glycocalyx” (Fig. 2, MV).

New observations of colloid cysts of the third ventricle: An ultrastructural study of the lining epithelium and the wall

1991 ◽  
Vol 49 ◽  
pp. 94-95
Author(s):  
Khang-Loon Ho ◽  
Julio H. Garcia
Keyword(s):  
Secretory Granules ◽  
Third Ventricle ◽  
Cell Types ◽  
Colloid Cyst ◽  
Basal Cells ◽  
Ciliated Cells ◽  
The Third ◽  
Undifferentiated Cells ◽  
Colloid Cysts ◽  
Dense Core Granules

Colloid cysts of the third ventricle represent one of the variety of the epithelial-lined cysts of the neuraxis. Their histogenesis remains unsettled. Ultrastructural and immunohistochemical analyses have suggested the following possible origins: (a) neuroectoderm, including paraphysis, ependyma, choroid plexus, and tela choroidea and (b) endoderm, including respiratory and enteric epithelium.This report describes the ultrastructure of the lining epithelium and the wall of four cases of colloid cyst. Six distinct cell types were recognized in the epithelium (Fig.1,2): (1) ciliated cells with various types of ciliary abnormalities, (2) non-ciliated cells with microvilli coated with granulo-fibrillary material, (3) goblet cells showing discharge of secretory granules, (4) basal cells with prominent tonofilaments, (5) basal-located cells with elongated cell bodies parallel to the basement membrane and electron-lucent cytoplasm containing sparse, membrane-bound dense core granules (150-250 nm) and (6) small undifferentiated cells with scanty organelles.

scholarly journals The larval midgut of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae): light and electron microscopy studies of the epithelial cells

2004 ◽  
Vol 64 (3b) ◽  
pp. 633-638 ◽  
Author(s):  
S. M. Levy ◽  
A. M. F. Falleiros ◽  
E. A. Gregório ◽  
N. R. Arrebola ◽  
L. A. Toledo
Keyword(s):  
Electron Microscopy ◽  
Endocrine Cells ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Anticarsia Gemmatalis ◽  
Epithelial Tissue ◽  
Basal Region ◽  
Transmission Electron ◽  
Basal Portion

The morphology of the midgut epithelium cells of Anticarsia gemmatalis (Hübner) larvae is described by light and transmission electron microscopy. The midgut of A. gemmatalis is the largest portion of the digestive tract, with three distinct regions: proximal, media and distal. Its wall is formed by pseudostratified columnar epithelial tissue having four cell types: columnar, goblet, regenerative, and endocrine cells. The columnar cells are numerous and long, with the apical portion showing many lengthy microvilli and the basal portion invaginations forming a basal labyrinth. The goblet cells have a large goblet-shaped central cavity delimited by cytoplasmic projections filled with mitochondria. The regenerative cells present electron-dense cytoplasm and few organelles. The endocrine cells are characterized by electron-dense secretory granules, usually concentrated in the cytoplasm basal region.

scholarly journals THE ANATOMIC SITE OF THE TRANSEPITHELIAL PERMEABILITY BARRIERS OF TOAD BLADDER

1969 ◽  
Vol 40 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Donald R. DiBona ◽  
Mortimer M. Civan ◽  
Alexander Leaf
Keyword(s):  
Basement Membrane ◽  
Plasma Membranes ◽  
Cell Layer ◽  
Single Layer ◽  
Cell Types ◽  
Physiological Data ◽  
Basal Cells ◽  
Granular Cells ◽  
Anatomic Site ◽  
Mucosal Epithelium

An examination of the mucosal epithelium of the urinary bladder of the toad reveals that the two major cell types which abut on the urinary surface, the granular and mitochondria-rich cells, also contact the basement membrane. Thus, the epithelium functions as a single cell layer. Although basal cells are interpolated between the granular cells and the basement membrane over a large portion of the epithelium, they do not constitute an additional continuous cell layer. This finding is consistent with extensive physiological data which had assumed that the major permeability barriers of this epithelium were the apical and basal-lateral plasma membranes of a single layer of cells.

scholarly journals The Olfactory Mucosa of the Sheep

1970 ◽  
Vol 23 (2) ◽  
pp. 447 ◽  
Author(s):  
Jean E Kratzing
Keyword(s):  
Electron Microscopy ◽  
Lamina Propria ◽  
Light And Electron Microscopy ◽  
Free Edge ◽  
Cell Types ◽  
Olfactory Nerve ◽  
Olfactory Mucosa ◽  
Basal Cells ◽  
Supporting Cells ◽  
Receptor Cells

The olfactory mucosa of the sheep was studied by light and electron microscopy. The epithelium conforms to the general vertebrate pattern and consists of olfactory receptor cells, supporting, and basal cells. The free edge of the epithelium is made up of long microvilli from the supporting cells and olfactory rods of the receptor cells, each carrying 40-50 cilia. All cell types contain large dark granules which may be the site of olfactory pigment. The basement membrane is not visible in light microscopy and is fine and discontinuous in electron microscopy. Bowman's glands are simple, tubular, mucus-secreting glands in the lamina propria. Their cells contain basal granules resembling those in the epithelial cells. The lamina propria also contains bundles of fine, unmyelinated, olfactory nerve fibres which are the proximal continuations of the receptor cells.

Ultrastructure of the oviductal mucosa of Leptodactylus chaquensis. Analysis of the preovulatory and postovulatory periods

Zygote ◽  
2014 ◽  
Vol 23 (5) ◽  
pp. 635-643
Author(s):  
Marcela Fátima Medina ◽  
Inés Ramos ◽  
Claudia A. Crespo ◽  
Susana Cisint ◽  
Lucrecia Iruzubieta Villagra ◽  
...  
Keyword(s):  
Secretory Granules ◽  
Cell Types ◽  
Secretory Cells ◽  
Ultrastructural Organization ◽  
Basal Region ◽  
Basal Cells ◽  
Ciliated Cells ◽  
Different Cell Types ◽  
Electron Lucent ◽  
Leptodactylus Chaquensis

SummaryIn the present study we analysed the ultrastructural characteristics of the oviductal mucosa of Leptodactylus chaquensis during the preovulatory period and immediately after ovulation. Epithelial secretory cells, ciliated cells, basal cells and glandular secretory cells are described. During the preovulatory period, the oviduct exhibits its maximum degree of development at both the epithelial and the glandular levels, with numerous secretory cells that contain a large number of secretory granules whose contents are released into the oviductal lumen by apocrine and exocytotic secretory processes. The secretory cells present throughout the oviduct display considerable variability in the characteristics of their secretory granules, which show different shapes, sizes, organization of the material contained and electron density. The different cell types are distributed following a characteristic pattern for each oviductal zone, thus creating an ultrastructural mosaic along the oviduct. During the postovulatory period, the number of secretory cells decreases and the remaining ones exhibit a marked reduction in secretory granules. Ciliated cells show a typical ultrastructural organization that is not modified throughout the reproductive cycle. Basal cells, located at the basal region of the epithelium, are characterized by their heterochromatic nuclei and electron-lucent cytoplasm, while glandular secretory cells exhibit oval, round or polyhedric granules, most of them with a prominent core. Our results, which indicate a high heterogeneity of secretory cell contents, allow us to suggest differential synthesis and secretion of specific products in each oviductal zone.

Ultrastructural Study of a differentiating human colon carcinoma cell line

1990 ◽  
Vol 48 (3) ◽  
pp. 208-209
Author(s):  
Sylvie Polak-Charcon ◽  
Mehrdad Hekmati ◽  
Yehuda Ben Shaul
Keyword(s):  
Cell Line ◽  
Morphological Changes ◽  
Secretory Granules ◽  
Human Colon ◽  
Cell Types ◽  
Culture Conditions ◽  
Morphological Evidence ◽  
Human Colon Carcinoma Cell ◽  
Colon Cell

The epithelium of normal human colon mucosa “in vivo” exhibits a gradual pattern of differentiation as undifferentiated stem cells from the base of the crypt of “lieberkuhn” rapidly divide, differentiate and migrate toward the free surface. The major differentiated cell type of the intestine observed are: absorptive cells displaying brush border, goblet cells containing mucous granules, Paneth and endocrine cells containing dense secretory granules. These different cell types are also found in the intestine of the 13-14 week old embryo.We present here morphological evidence showing that HT29, an adenocarcinoma of the human colon cell line, can differentiate into various cell types by changing the growth and culture conditions and mimic morphological changes found during development of the intestine in the human embryo.HT29 cells grown in tissue-culture dishes in DMEM and 10% FCS form at late confluence a multilayer of morphologically undifferentiated cell culture covered with irregular microvilli, and devoid of tight junctions (Figs 1-3).

LIGHT AND ELECTRON MICROSCOPICAL STUDY OF THE EFFECT OF OESTROGEN ON THE CHICKEN OVIDUCT

1967 ◽  
Vol 56 (3) ◽  
pp. 391-402 ◽  
Author(s):  
H. I. Ljungkvist
Keyword(s):  
Secretory Granules ◽  
Apical Cell ◽  
Cell Types ◽  
Microscopical Study ◽  
List Type ◽  
New Production ◽  
General Increase ◽  
Chicken Oviduct ◽  
Electron Microscopical ◽  
Aortic Perfusion

ABSTRACT Oviducts from 20 one-day old chickens were used. Ten chickens were injected subcutaneously with 0.2 mg oestradiol for 5 days, the remaining ones serving as controls. The chickens were fixed by an aortic perfusion with 2.5% glutaraldehyde in phosphate buffer, pH 7.2. The treatment with oestrogen resulted in the following changes: general increase in oviduct length and thickness, differentiation of the epithelial membrane into three cell types: basal, apical and gland cells, increase in the number of cilia in the apical cell, probably due to a new production of cilia, formation of secretory granules in the vaginal epithelium as seen by light microscopy, formation of proteinlike secretory granules in the apical cell as seen by electron microscopy, increase in protein synthesis, observed as an augmentation of the endoplasmic reticulum.

Ultrastructure of the basal lamina of bovine ovarian follicles and its relationship to the membrana granulosa

Reproduction ◽  
2000 ◽  
pp. 221-228 ◽  
Author(s):  
HF Irving-Rodgers ◽  
RJ Rodgers
Keyword(s):  
Basal Lamina ◽  
Granulosa Cells ◽  
Light And Electron Microscopy ◽  
Single Layer ◽  
Antral Follicle ◽  
Basal Cells ◽  
Preantral Follicles ◽  
Antral Follicles ◽  
Cellular Processes ◽  
Innermost Layer

Different morphological phenotypes of follicular basal lamina and of membrana granulosa have been observed. Ten preantral follicles (< 0. 1 mm), and 17 healthy and six atretic antral follicles (0.5-12 mm in diameter) were processed for light and electron microscopy to investigate the relationship the between follicular basal lamina and membrana granulosa. Within each antral follicle, the shape of the basal cells of the membrana granulosa was uniform, and either rounded or columnar. There were equal proportions of follicles </= 4 mm in diameter with columnar basal cells and with rounded basal cells. Larger follicles had only rounded basal cells. Conventional basal laminae of a single layer adjacent to the basal granulosa cells were observed in healthy follicles at the preantral and antral stages. However, at the preantral stage, the conventional types of basal lamina were enlarged or even partially laminated. A second type of basal lamina, described as 'loopy', occurred in about half the preantral follicles and in half the antral follicles </= 4 mm diameter. 'Loopy' basal laminae were not observed in larger follicles. 'Loopy' basal laminae were composed of basal laminae aligning the basal surface of basal granulosa cells, but with additional layers or loops often branching from the innermost layer. Each loop was usually < 1 microm long and had vesicles (20-30 nm) attached to the inner aspect. Basal cellular processes were also common, and vesicles could be seen budding off from these processes. In antral follicles, conventional basal laminae occurred in follicles with rounded basal granulosa cells. Other follicles with columnar cells, and atretic follicles, had the 'loopy' basal lamina phenotype. Thus, follicles have different basal laminae that relate to the morphology of the membrana granulosa.

scholarly journals Anaphylactic Degranulation of Mast Cells: Focus on Compound Exocytosis

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ofir Klein ◽  
Ronit Sagi-Eisenberg
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Molecular Mechanisms ◽  
Secretory Granules ◽  
Cell Types ◽  
Secretory Cells ◽  
Regulated Exocytosis ◽  
Open Questions ◽  
Conflicting Evidence ◽  
Compound Exocytosis

Anaphylaxis is a notorious type 2 immune response which may result in a systemic response and lead to death. A precondition for the unfolding of the anaphylactic shock is the secretion of inflammatory mediators from mast cells in response to an allergen, mostly through activation of the cells via the IgE-dependent pathway. While mast cells are specialized secretory cells that can secrete through a variety of exocytic modes, the most predominant mode exerted by the mast cell during anaphylaxis is compound exocytosis—a specialized form of regulated exocytosis where secretory granules fuse to one another. Here, we review the modes of regulated exocytosis in the mast cell and focus on compound exocytosis. We review historical landmarks in the research of compound exocytosis in mast cells and the methods available for investigating compound exocytosis. We also review the molecular mechanisms reported to underlie compound exocytosis in mast cells and expand further with reviewing key findings from other cell types. Finally, we discuss the possible reasons for the mast cell to utilize compound exocytosis during anaphylaxis, the conflicting evidence in different mast cell models, and the open questions in the field which remain to be answered.

Pituitary adenoma producing growth hormone and adrenocorticotropin: a histological, immunocytochemical, electron microscopic, and in situ hybridization study

1998 ◽  
Vol 88 (6) ◽  
pp. 1111-1115 ◽  
Author(s):  
Kalman Kovacs ◽  
Eva Horvath ◽  
Lucia Stefaneanu ◽  
Juan Bilbao ◽  
William Singer ◽  
...  
Keyword(s):  
Growth Hormone ◽  
In Situ Hybridization ◽  
Pituitary Adenoma ◽  
Immunoelectron Microscopy ◽  
Secretory Granules ◽  
Cell Types ◽  
Content Type ◽  
Separate Cell ◽  
Fine Print

✓ The authors report on the morphological features of a pituitary adenoma that produced growth hormone (GH) and adrenocorticotropic hormone (ACTH). This hormone combination produced by a single adenoma is extremely rare; a review of the available literature showed that only one previous case has been published. The tumor, which was removed from a 62-year-old man with acromegaly, was studied by histological and immunocytochemical analyses, transmission electron microscopy, immunoelectron microscopy, and in situ hybridization. When the authors used light microscopy, the tumor appeared to be a bimorphous mixed pituitary adenoma composed of two separate cell types: one cell population synthesized GH and the other ACTH. The cytogenesis of pituitary adenomas that produce more than one hormone is obscure. It may be that two separate cells—one somatotroph and one corticotroph—transformed into neoplastic cells, or that the adenoma arose in a common stem cell that differentiated into two separate cell types. In this case immunoelectron microscopy conclusively demonstrated ACTH in the secretory granules of several somatotrophs. This was associated with a change in the morphological characteristics of secretory granules. Thus it is possible that the tumor was originally a somatotropic adenoma that began to produce ACTH as a result of mutations that occurred during tumor progression.

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