On the welcome page of the dictionary, three major sections are shown: Normal tissues, Cancer and Cell structure. Below the image of each section are links to introductory texts for i) normal tissue histology, ii) hallmarks of cancer, and iii) cell structure overview. For the cancer-section there is also a link to current cancer statistics (incidence, survival, etc) for Sweden and the rest of the world. Within each section there are direct links to histology descriptions of different tissue types and tumor forms as well as descriptions of cell structures.
For the 'Tissue & cell types' and 'Tumor' sections, tissue-slides stained with hematoxylin and eosin (HE) are shown at three different levels of magnification. On the top level, an overview of the whole tissue-sample is shown with boxes in black indicating where zoomed-in representative parts of the tissue are available for viewing. Clicking on these boxes will zoom in on that part to show tissue structures, cells and features in greater detail. Throughout these sections, arrows indicate relevant tissue structures, cell-types and other features.
For the 'Cell structure' section, immunofluorescent images of formaldehyde-fixed cell lines are shown. The various cell structures that are demonstrated are always shown in the green channel using an antibody found in the Human Protein Atlas. The antibody name is linked to the subcellular location summary page of the target gene. The other channels: nucleus, microtubules and endoplasmic reticulum, are always shown in the blue, red and yellow channels, respectively. The channels can be toggled on and off by clicking on the respective coloured button above the image. When applicable, the immunofluorescent images are complemented by immunohistochemically stained cells where the location of the particular cell structure is shown in brown.
A common feature for all sections is that a general descriptive text about the tissue, tumor-type or cell structure is provided when browsing a particular topic.
Bronchi are tube like structures that allow air to be transported from the surrounding atmosphere to the lung. The respiratory system (airways) consists of the trachea (essentially a large bronchus) that branch off into smaller and smaller bronchi before reaching the most distal lung alveoli, where oxygen can be transferred to the blood.
The respiratory bronchus is lined by respiratory epithelium comprising an admixture of pseudo stratified ciliated columnar epithelium, goblet cells (mucin producing cells also termed mucous cells) and basal cells that function as progenitor cells for both the ciliated columnar cells and goblet cells. Ciliated cells are about five times more numerous than goblet cells in the central airways and the ratio of ciliated cells increases in the smaller and peripheral bronchi (bronchioles) as the goblet cells diminish. The basal cells are more abundant in the proximal airways, where they form more or less, a continuous layer and gradually diminish in number in peripheral bronchi. Small clusters of neuroendocrine cells located within the bronchial epithelium called neuropeithelial bodies can be identified.
The subepithelial tissue can be divided into a lamina propria situated between the basement membrane and the muscularis mucosae, and a submucosa. The lamina propria contains a network of capillaries, reticulin fibers and bundles of elastic and nerve fibers. The submucosa of larger bronchi contains cartilage with chondrocytes, muscle tissue as well as serous and mucous glands, termed peribronchial glands. Anatomically, three regions can be recognized in these glands: the ciliated duct, the connecting duct, and the secretory tubules lined by serous and mucinous glandular cells. A myoepithelial cell layer is also present.
