Endocrine, paracrine and intracrine mechanisms of growth regulation in normal and malignant endometrial epithelium
A. R. Genazzani in Hormone Replacement Therapy and Cancer, 2020
The different endometrial cell types are surrounded by the extracellular matrix (ECM), which also shows cyclic changes during the menstrual cycle (Figure 1). The ECM can be separated into two types. The first is the interstitial matrix, which is a collagen-rich ground substance (contains collagen types I, II, III, V, VI and XI, glycosaminoglycans, proteoglycans and fibronectin), in which stromal fibroblasts are located. The components of the interstitial matrix are synthesized by stromal fibroblasts. The second is the basement membrane, which is the specialized matrix (contains collagen IV, the glycoproteins laminin and entactin, and heparan sulfate proteoglycans) underlying epithelial and endothelial cell layers. Epithelial cells may synthesize components of their own basal lamina. Basement membranes also surround muscle, fat and decidual cells, as well as vascular smooth muscle cells and endothelial cells.
Fibrogenic Cytokines in Airway Fibrosis
Alastair G. Stewart in AIRWAY WALL REMODELLING in ASTHMA, 2020
In the normal airway, there are several readily distinguishable layers by light microscopy, namely, surface epithelium, basement membrane, lamina propria, smooth muscle, submucosa, cartilage, and adventitia. Ultrastructurally, the basement membrane of the human airway consists of two distinct layers: a basal lamina and a reticular collagenous lamina (Figure 2).18,28 The basal lamina (true basement membrane) largely comprises type IV collagen, proteoglycans, laminin, and fibronectin. The reticular collagenous lamina or subepithelial collagen layer predominandy comprises types III and V collagen together with fibronectin.20 Beneath this is a bed of stromal tissue predominandy comprised of mesenchymal cells, fibroblasts, and smooth muscle cells, embedded in matrix. The matrix substance of normal airways, like other organs, is composed of a wide array of immunologically and biochemically distinct elements: collagens (collagens I, III, V), elastins, proteoglycans, fibronectins, and laminins (Plate 1* and Figure 3). The major components, collagens (types I and III) and elastin, are the primary determinants of the physical properties of bronchioles. In the upper airway there is the additional support to the cartilaginous structures composed predominantly of type II collagen.29
Ultrastructure of Human Gastrointestinal System. Interactions Among Mast Cells, Eosinophils, Nerves and Muscle in Human Disease.
William J. Snape, Stephen M. Collins in Effects of Immune Cells and Inflammation on Smooth Muscle and Enteric Nerves, 2020
Enteric autonomic nerves and their associated Schwann cells comprise the nerve collections between muscle layers in the submucosa and elsewhere in gut tissues. Only a few salient ultrastructural features of the structure and distribution of this complex system can be presented here. In cross-sections examined by light and electron microscopy, large ganglion cells surrounded by nerve cell processes and Schwann cells are readily apparent. Many sections, however, contain only cross- and longitudinal sections of Schwann cell cytoplasm-invested bundles of nerve cell processes (Figure 6). While some of these nerve cell processes can be seen to originate from local ganglion cells, most do not, having their cellular origins at other levels in the gut or in autonomic ganglia remote from the gastrointestinal tract. It is important to recognize the Schwann cell-neurite fascicles by the identification of characteristic organelles and associations. Schwann cells are small, spindle-shaped cells with extensive free and membrane-bound ribosomes. These cells are invested by basal lamina.
The ultrastructural effects of surgical treatment of hydrosalpinx on the human endometrium: a light and electron microscopic study
Published in Ultrastructural Pathology, 2019
Tuğçe Sapmaz, Leman Sencar Gündoğdu, Mehmet Turan Çetin, Ibrahim Ferhat Ürünsak, Sait Polat
Ultrastructural examination of the endometrial tissue samples obtained from the patients with hydrosalpinx after surgical treatment, it was observed that the surface epithelium consisted of microvilli and ciliated columnar cells. It was interesting that the surface epithelium showed slight structural changes in some areas, but in most areas, its structure was more similar to control endometrium. It was determined that epithelial, glandular and stromal structures of endometrial tissues obtained after surgical treatment were similar to normal endometrium in general. Furthermore, the presence of pinopod structures formed by the apical cytoplasm of the endometrial columnar epithelial cell extending towards the lumen was observed. The nuclei of the epithelial cells had a thin, long, oval shape, and the nucleus usually were located at the base of the cell. It was observed that the cell nuclei had usually euchromatic appearance and contained one or more nucleoli in the nucleus. Normal, thin and long mitochondria, GER cisternae and Golgi complex, lipid droplets, vacuoles and glycogen particles in the cytoplasm were also observed in the cytoplasm of the cells. A thin basal lamina was noted at the lower part of the epithelium. Stromal cells in the endometrial stroma were usually round or oval in shape, with cytoplasmic organelles in normal structure and lipid droplets in some cells (Figures 13–15). Blood vessels and connective tissue fibers were also found in the stroma.
Expression and role of HIF-1α and HIF-2α in tissue regeneration: a study of hypoxia in house gecko tail regeneration
Published in Organogenesis, 2019
Titta Novianti, Vetnizah Juniantito, Ahmad Aulia Jusuf, Evy Ayu Arida, Sri Widia A. Jusman, Mohamad Sadikin
On day 1, the tail tissue was invaded by leucocyte cells, indicating an inflammation process. Erythrocyte cells typically dominate in tissue injuries, and their presence in the injury site here have I cated that there was bleeding in this area. In the tissue area, some cells proliferated in the basal lamina and migrated to form a new epithelial layer covering the injury site. On day 3, ganglion neuron cells had formed and spread in the dermis tissue, but the tissue was still dominated by leucocyte and erythrocyte cells, and the basal lamina cells had continued to spread and migrate to the epithelial layer. On day 5, the epithelial layer had become thicker, and endothelial cells appeared in the dermis tissue layer. On day 8, the newly regenerated tissue s dominated by fibroblast-like cells and neuronal cells. On day 10, cell aggregation was observed, and the structure of the dermis and epidermis layers was more compact. Some stem cells were found in the aggregated cells, indicating the beginning of the blastemal phase (Fig. 2).
Ultrastructural evidence for presenсe of gap junctions in rare case of pleomorphic xanthoastrocytoma
Published in Ultrastructural Pathology, 2020
Evgeniya Yu. Kirichenko, Sehweil Salah M. M., Zoya A. Goncharova, Aleksei G. Nikitin, Svetlana Yu. Filippova, Sergey S. Todorov, Marina A. Akimenko, Alexander K. Logvinov
Tumor cells of PXA were represented by large polygonal mononuclear or multinuclear xanthastrocytes, with dark cytoplasm due to the presence of multiple gliofibrills. The nuclei of these cells had dark karyoplasm, irregular shape with deepenings and invaginations, sometimes without clear boundaries of the karyolemma. The longitudinal processes of such cells were filled with bundles of gliofibrills and could contact the bodies of other cells. Among the cellular organelles, the Golgi complex, RER, mitochondria, and intermediate filaments, which often displace other organelles, were noted. Also, the cytoplasm of such cells contained various inclusions: multiple lipid drops, not limited by the membrane, primary and secondary lysosomes of various calibers, as well as lipofuscin granules (Figure 2a). Another type of PXA cells had less dark cytoplasm due to the lower content of gliofibrils: as a rule, they have elongated bodies with elongated nuclei, light karyolemma and invaginations. The presence of a basal lamina surrounding single cells as well as small groups of cells was noted (Figure 1h). The tumor intercellular space consisted of predominantly small processes of various caliber containing gliofibrills.
Related Knowledge Centers
- Anchoring Fibrils
- Basement Membrane
- Epithelium
- Reticular Fiber
- Stratified Squamous Epithelium
- Lamina Propria
- Extracellular Matrix
- Pulmonary Alveolus
- Lamina Lucida
- Lamina Densa