Cuboidal cells

Where the terms have been previously described. As a first approximation, we have assumed here that the lateral space is a rectangular slit between cuboidal cells. The porosity, the fractional area of the cell monolayer in the paracellular space, is calculated as... 

It has been postulated that wood dust carcinoma results from a multistep process Exposure causes loss of cilia and hyperplasia of the goblet cells and initiation of cuboidal cell metaplasia, followed (after a quiescent period) by squamous cell metaplasia. Decades later, cellular aplasia leads to nasal adenocarcinoma. The time between first occupational exposure to wood dust and the development of nasal cavity adenocarcinoma averages 40 years. Other cancers, including lung cancer, Hodgkin disease, multiple myeloma, stomach cancer, and colorectal cancer and lymphosarcoma, have been mentioned in relation to wood... 

Epidermis. The epidermis is a 50- to lOO-pm-thick layer made of ker-atinocytes that migrate outward from the basal cell into highly differentiated nondividing cells.46,47 During differentiation, keratinocytes transform from polygonal (cuboidal) cells to spinous (prickly) cells, flattened granular cells, and finally to flattened polyhedral dead corneocytes full of the protein keratin.45,47... 

The pharynx, larynx, trachea and bronchi are lined with pseudostratified, ciliated columnar epithelium that contain at least eight cell types, including mucous secretory goblet and Clara cells, which produce a protective mucus layer of 5-10 jum thickness (see Table 9.2). Subepithelial secretory glands, present in the bronchial submucosa, also contribute to the mucus blanket [9]. Through coordinated ciliary movement a propulsive wave is created, which continuously moves the mucus layer up towards the larynx. Consequently, the mucosal surface of trachea and bronchi is constantly swept to remove inhaled materials. As the bronchi divide into bronchioli, the ciliated columnar respiratory epithelium is much thinner and changes to a simpler non-ciliated cuboidal epithelium. The epithelium in the terminal and respiratory bronchioles consists of ciliated, cuboidal cells and a small number of Clara cells. However, Clara cells become the most predominant type in the most distal part of the respiratory bronchioles [10]. 

Bronchioles, terminal bronchioles 12-16 1.0-0.4 Ciliated cuboidal cell Clara cell Serous cell 10... 

The pulmonary alveolar epithelium is comprised of two morphologically distinct cells, type I and type II cells. Type I cells are extremely large, squamous cells that make up 95% of the alveolar surface. Type II cells are smaller cuboidal cells that secrete and recycle surfactant and cover the remaining 5% of the alveolar surface. Mechanical distention of fetal lung tissue has been shown to stimulate expression of the type I cell phenotype and inhibit expression of the type II phenotype. Lumenal mechanical stim-... 

These are primarily lined with ciliated cuboidal cells. The frequency of goblet and serous cells decreases with progression along the airways while the number of Clara cells increases. The epithelium is much thinner and there is less mucus in this region. 

Type-II pneumocytes cuboidal cells that store and secrete pulmonary surfactant. 

Appendageal structures commonly found within the skin are the hairs, hair follicles, associated sebaceous glands, apocrine and eccrine sweat glands, and arrector pili muscles. Hairs are formed by epidermal invaginations. These keratinized structures traverse the dermis and may extend into the hypodermis. The free part of the hair above the surface of the skin is the hair shaft, and the part deep within the dermis is the hair root, which forms an expanded knob-like structure called the hair bulb. This is composed of a matrix of epithelial cells in different stages of differentiation. Hair is composed of three concentric epithelial cell layers the outermost thin cuticle, a densely packed keratinized cortex, and a central medulla of cuboidal cells. The hair follicle consists of four major components (1) internal root sheath (internal root sheath cuticle, granular layer, pale epithelial layer) (2) external root sheath (several layers similar to the epidermis) (3) dermal papilla (connective tissue) and (4) hair matrix (comparable to the stratum basale of the epidermis). 

Cuboidal cells have a shape similar to a cube, which means that their width is the same as their height. 

Carcinoid tumor, metastatic, lung 80 primary Sclerosing hemangioma of 100 lung—cuboidal cells and polygonal cells... 

Some epithelial mesotheliomas are composed of small cysts formed by uniform cuboidal mesothelial cells and associated numerous blood vessels (Fig. 12.68). This type of mesothelioma may be difficult to differentiate from a vascular neoplasm. The epithelial mesothelial cells may contain intracytoplasmic hemosiderin (Fig. 12.69). The immunophenotype of such neoplasms is identical to that of other epithelial mesotheliomas. The vascular proliferation may be related to an endothelial growth factor produced by neoplastic mesothelial cells.Adenomatoid tumors are localized benign mesothelial proliferations that most frequently occur in the epididymus and cornua of the uterus.Adenomatoid tumors have been identified in the adrenal gland and pancreas. These tumors are formed by uniform small cuboidal cells and can appear invasive. They express keratin and other markers of mesothelial cells and have the characteristic ultrastruc-tural features of mesothelial cells. Adenomatoid tumors have also been reported in the pleura. Hyperplastic... 

FIGURE 12.67 This well-differentiated papillary epithelial mesothelioma involving pleura shows papillary differentiation and is composed of relatively small, uniform cuboidal cells. This type of mesothelioma usually pursues a benign clinical course. X 200. 

Another recently proposed classification system, which pertains mainly to adenoma in the EHBDs, divides them into two categories on the basis of the predominant cytologic features columnar-cell and cuboidal-cell types." This is analogous to the villous/intestinal and pancreatobiliary subsets of pancreatic IPMNs, respectively. ... 

Figure 4.18 Tortuosity as a function of porosity for randomly oriented porous media. For diffusion in porous materials, the length of the diffusional path is increased. If the pores are randomly oriented, and large enough to permit random molecular trajectories, the tortuosity is a function of total porosity. Equation 4-46 (dashed line). The tortuosity predicted for diffusion around a lattice of sparsely populated spheres is obtained from Equation 4-43 assuming completely impermeable spheres (heavy dashed line). Tortuosities for ensembles of cuboidal cells are also included (triangles). The solid lines without symbols indicate tortuosity for a Bethe lattice of coordination number 4 or 7.

Hurthle cell Cords of large polygonal or cuboidal cells with eosinophilic granular cytoplasm and small hyperchromic nuclei... 

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