Connective tissue basement membrane

CAS 86088-83-7 EINECS/ELINCS 289-149-2 Definition Glycoprotein found in connective tissues, basement membranes, plasma, and other body fluids Properties Solid... 

The formation of supramolecular assemblies of ECM biopolymers defines an obvious and highly important interconnection of physical and biospecific characteristics of the matrices. In general, multiple specific interactions between individual biopolymers, such as collagen or fibronectin, result in the formation of large fibrillar or meshwork-like structures segmenting tissues and guiding cells by microstructural features and mechanical characteristics. With those structures, often referred to as connective tissue, basement membrane, and several others, the unique functionality of ECM and the fact that it is based on both the provision of specific binding sites and physical forces is best represented. 

Airway cross-sections have the nominal anatomy shown in Fig. 5.16. Airway surface liquid (AST), primarily composed of mucus gel and water, surrounds the airway lumen with a thickness thought to vary from 5 to 10 mm. AST lies on the apical surface of airway epithelial cells (mostly columnar ciliated epithelium). This layer of cells, roughly two to three cells thick in proximal airways and eventually thinning to a single cell thickness in distal airways, rests along a basement membrane on its basal surface. Connective tissue (collagen fibers, basement membranes, elastin, and water) lies between the basement membrane and airway smooth muscle. Edema occurs when the volume of water within the connective tissue increases considerably. Interspersed within the smooth muscle are respiratory supply vessels (capillaries, arteriovenous anastomoses), nerves, and lymphatic vessels. 

The basement membrane is a structure that supports overlying epithelial or endothelial cells. The primary fimction of the basement membrane is to anchor down the epithelium to its loose connective tissue underneath. This is achieved by cell-matrix adhesions through cell adhesion molecules. 

In biology, extracellular matrix (ECM) is the extracellular part of animal tissue that usually provides structural support to the cells in addition to performing various other important functions. ECM is the defining feature of connective tissue in animals. ECM includes the interstitial matrix and the basement membrane. 

The innermost layer of an artery, which consists of loose connective tissue covered by a monolayer of endothelium that resides on a basement membrane. In human arteries, the intima often contains resident smooth muscle cells even early in life. Atherosclerotic plaques form in the intima. 

Malignant cells are divided into categories based on the cells of origin. Carcinomas arise from epithelial cells, whereas sarcomas arise from muscle or connective tissue. Adenocarcinomas arise from glandular tissue. Carcinoma in situ refers to cells limited to epithelial origin that have not yet invaded the basement membrane. 

Unlike the acellular basement membranes, the interstitial connective tissue consists of cells distributed in meshwork of collagen fibers, glycoproteins (e.g., fibronectin), proteoglycans, and hyaluronic acid. The main forms of collagen found in interstitial connective tissue are known as type I, II, and III or interstitial collagen. 

The tracheo-bronchial epithelium forms the interface between the conducting airways and inspired air. As described above, the epithelium is layered upon a connective tissue substratum consisting of a basement membrane, lamina propria, and submucosa [6], The submucosa contains elastic fibres, a muscularis mucosa, connective tissues and seromucous glands. Lymphatics are also located in the bronchial walls [2],... 

The oral mucosa is anatomically divided into three tissue layers (Fig. 1) [10] the epithelium, the basement membrane, and the connective tissues. 

The basement membrane (BM) is a continuous layer of extracellular materials, forming a boundary between the basal layer of the epithelium and the connective tissues of the lamina propria and the submucosa. It can be subdivided into the lamina lucida,... 

Figure 1.10 Columnar and stratified epithelia. Epithelial b ssues are underlain by a basement membrane which is a composite structure composed of an amorphous basal lamina, secreted by the epithelial cells, and a more fibrous reticular lamina derived from connective tissue.

Figure 8-1 Electron micrograph of a thin section of a fat storage cell or adipocyte. L, the single large fat droplet N, nucleus M, mitochondria En, endothelium of a capillary containing an erythrocyte (E) CT, connective tissue ground substance which contains collagen fibers (Co) and fibroblasts (F). The basement membranes (BM) surrounding the endothelium and the fat cell are also marked. From Porter and Bonneville.6 Courtesy of Mary Bonneville.

Our own skin is made up of specialized cells which become filled with microfibrils of keratin as they move outward and become the relatively dry nonliving external surface (Box 8-F). Internal epithelial cells secrete protein and carbohydrate materials that form a thin basement membrane around the exposed parts of the cells. The connective tissue that lies between organs and which also includes tendons, cartilage, and bone consists of a relatively small number of cells surrounded by a "matrix" consisting of the protein fibers collagen and elastin in a "ground substance" rich in proteoglycans (Chapter 4).616 618 in bone, the calcium phosphate is deposited within this matrix. 

Beneath die basement membrane of the epidermis is the dermis, a thick, tough, collagen-rich connective tissue. Blood vessels and nerve endings are found in this layer, as are roots of hairs and oil and sweat glands.1 ... 

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