Connective collagen

Similar descriptions apply to animal tissues, except that the cellular materials can themselves be fibrous (as in muscle) within a fibrous network of connecting collagen. This complexity is far greater than is found in engineering materials for which the mathematical understanding of composite materials has been developed. Worse, biological materials deform by large amounts (more than 1%) and are nonlinear, both... 

Scieroproteins. Insoluble proteins obtained from the skeletal and connective tissues of animals. Typical classes are keratins collagens and elastin classes. 

Kielty, C.M., Hopkinson, 1., Grant, M.E. Collagen structure, assembly and organization in the extracellular matrix. In Connective Tissue and its Heritable Disorders Wiley-Liss, Chichester, pp. 103-147, 1993. 

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. 

Collagen is a rigid, inextensible fibrous protein that is a principal constituent of connective tissue in animals, including tendons, cartilage, bones, teeth, skin, and blood vessels. The high tensile strength of collagen fibers in these struc-... 

Collagen is a major component of connective tissue that becomes exposed at the subendothelium of injured blood vessels. It contributes to platelet adhesion and also plays a role in platelet activation by binding to several receptors on platelets such as integrin a 2(3 1 or glycoprotein VI (GP VI). 

UV-B causes sunburn, but UV-A damages collagen (connective tissue) and blood vessels, causing aging effects such as wrinkled skin. 

Ascorbic acid—vitamin C—is an essential nutrient that the human body cannot manufacture from other compounds. It is needed for the formation of collagen, the protein that makes up connective tissue, and is essential to muscles, bones, cartilage, and blood vessels. It is a strong antioxidant, preventing damage from oxygen free radicals. 

Gelatin is a protein, made from the hydrolysis of collagen, a protein that makes up about a third of all mammalian tissue. Collagen is a key component of connective tissues, tendons, and bones. 

Collagen forms a triple helix, where three chains of connected amino acids form weak hydrogen bonds between the double-bonded oxygen atoms and the hydrogen atoms attached to the adjacent chain s nitrogens. The three chains then twist together like three cords in a rope. 

Collagen, the major component of most connective tissues, constimtes approximately 25% of the protein of mammals. It provides an extracellular framework for all metazoan animals and exists in virmally every animal tissue. At least 19 distinct types of collagen made up of 30 distinct polypeptide chains (each encoded by a separate gene) have been identified in human tissues. Although several of these are present only in small proportions, they may play important roles in determining the physical properties of specific tissues. In addition, a number of proteins (eg, the Clq component of the complement system, pulmonary surfactant proteins SP-A and SP-D) that are not classified as collagens have... 

Scleroproteins, insoluble in most solvents. Localized in connective tissue, bone, hair, and skin. The two principal classes are the collagens and keratins Nucleoproteins, nucleic acid... 

Skeletal muscle consists of muscle fibers linked together by connective tissue. Tendons and ligaments are composed of collagenous fibers that have a restricted capability to stretch. Tendons connect the muscle to the bone, whereas ligaments connect bone to bone (Fig. 57-1). 

Collagen is the most abundant animal protein in the body of animals, where it makes up as much as one-quarter of all the proteins. It is a fibrous protein that provides structure to and protects and supports soft tissues it also connects tissues to the skeleton. Collagen forms, for example, most of the resilient layers that make up the skin and the filaments that support the internal organs. Interwoven with bioinorganic components, collagen also makes up the bones and teeth of vertebrate animals (see Chapter 15). 

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