A graphic reconstruction has been made of a submucosal gland from a normal human main bronchus, revealing a collecting duct not previously described. Ciliated respiratory epithelium dips into the gland opening to line the first part of the duct, the ciliated duct, and then gives way, in the collecting duct, to an epithelium composed of tall, columnar, eosinophilic cells containing numerous large mitochondria. This cell structure suggests that the collecting duct controls ionic and water concentration. From the collecting duct arise secretory tubules lined by mucous cells-mucous tubules. Tubules lined by serous cells serous tubules-arise from mucous tubules either terminally or laterally.Submucosal glands are found in the normal human bronchial tree in those airways with cartilage in the wall. The glands lie between the epithelium and plates of cartilage and between, and occasionally external to, the plates of cartilage (Miller, 1947;Reid, 1968). They have been variously described as compound tubular, tubuloacinar, and racemose structures. Fuchs-Wolfring (1898) described two cell types-the mucous, and the serous or albuminous-and reported that sometimes the mucous cells were in continuity with high columnar epithelium.Recent electron microscopic studies have revealed in the bronchial glands a cell type not previously reported at this site (Meyrick and Reid, 1969). It is filled with numerous large mitochondria ( Fig. 1) and has a well-developed Golgi apparatus. Dense granules lie near the cell apex and lateral edges, and most cells include lipochondria. The plasma membrane of the base is flat and uncomplicated but the lateral surfaces interdigitate with adjacent cells. These cells are found next to mucous cells and are arranged as a tube. Myoepithelial cells are found in association with them as well as with the secretory cells.The present paper describes an extension of this study to light microscopy, which has revealed a central duct system in the bronchial gland lined with these cells. A description is also given of a reconstruction of the duct system and of the mucous and serous secretory tubules. MATERIALS AND METHODSPREPARATION OF TISSUES FOR LIGHT MICROSCOPY Specimens of bronchus were obtained at neoropsy and from surgical resection. The cases studied were either 'normal' or had a history of 'simple bronchitis'.Bronchial rings were examined from 20 cases, 17 men and 3 women, with an age range from 16 to 65 years. Fifteen of the specimens were obtained at resection and five at necropsy: of the latter, one was from a woman and four were from men. Resection specimens were from patients with carcinoma save for one who suffered from bronchiectasis: ,these specimens included main and lobar bronchi. The necropsy lungs were considered normal: these specimens included trachea and main bronchus. In total, there were three specimens of trachea, 13 of main bronchus, and four of lobar bronchus. The specimen used for the gland reconstruction was from a man, 63 years of age, who died from a dissecting aneurysm of the aort...
S U M M A R Y1. The incorporation of tritiated glucose into bronchial gland cells enables their glycoprotein secretion to be followed by radioautography. The number of cells from which secretion is observed after 4 h of cell culture is the secretory index.2. Large variations in secretory index were observed between the bronchi of different subjects, but the secretory index was proportional to gland size.3. The secretory index was increased by parasympathomimetic drugs and diminished by parasympatholytic drugs, the magnitude of the effect being proportional to gland size in the former and inversely proportional in the latter case.4. Sympathomimetic drugs, bradykinin and mucolytic drugs had no effect on the secretory index.5. In cystic fibrosis, bronchitis and bronchiectasis gland size and not the disease process was the main determinant of the secretory index.
The structure and ultrastructure were studied of 48 specimens from cases of congenital ureteroplevic junction obstructions and primary obstructive megaureters. Under light microscopy a spectrum of findings occurs, extending from the nearly normal to the clearly abnormal obstructive segments. However, under electron microscopy there were consistent abnormalities: 1) excessive collagen fibers between and around the muscle cells and 2) a group of compromised muscle cells proximal to the collagenous segment. These findings are responsible for functional discontinuity via the nexus and indistensibility of the pathologic areas. The high resolution of the electron microscope allows clearer definition of these obstructions and the impact of these findings on surgical remodeling is discussed.
Twenty-eight normal human ureters were examined under the light and electron microscope. Three uretero-trigonal units were microdissected. The ureter is a non-layered muscular tube wherein the anatomical unit is muscle bundles that contain heterogeneously oriented muscle cells. Functional continuity of muscle cells is provided through the nexus, which are clearly defined structures. A group of morphologically distinct muscle cells are identified and these may represent the ureteral pacemaker cells. The functional status of muscle cells causes certain morphologic changes and, thus, the cells fixed in contraction differ from those fixed in relaxation and in vitro testing of muscle cell contractility is feasible. The ultrastructure of the normal urothelium and the adrenergic and cholinergic components of ureteral nerves are presented briefly.
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