Which of the following types of collagen is present in basement membrane?
Ans. c. Type IV (Ref: Robbins 9/e p20-23. 8/e p95)Type IV collagens are the main components of the basement membrane, together with laminin."The basement membrane is synthesized by contributions from the overlying epithelium and underlying mesenchymal cells, forming a fiat lamellar "chicken wire " mesh (although labeled as a membrane, it is quite porous). The major constituents are amorphous nonfibrillar type IV collagen and laminin. "--Robbins 9/e p21.Type IV collagens have long but interrupted triple-helical domains and form sheets instead of fibrils; they are the main components of the basement membrane, together with laminin."--Robbins 9/e p23 Main Types of Collagens, Tissue Distribution, and Genetic DisordersCollagen TypeTissue DistributionGenetic DisordersFibrillar CollagensIUbiquitous in hard & soft tissues (Bone, cornea & myofibrilsQ)Osteogenesis imperfecta; Ehlers-Danlossyndrome-arthrochalasias type IIICartilage, intervertebral discQ, vitreousQAchondrogenesis type It, spondyloepiphysea dysplasia syndromeIIIHollow organs, soft tissues, granulation tissueQVascular Ehlers-Danlos syndromeVSoft tissues, blood vesselsQClassical Ehlers-Danlos syndromeIXCartilage, vitreousQStickler syndromeBasement Membrane CollagensIVBasement membranes, eye lensQAlport syndromeOther CollagensVIUbiquitous in microfibrilsBethlem myopathyVIIAnchoring fibrils at dermal-epidermal junctionsQDystrophic epidermolysis bullosaIXCartilage, intervertebral discsQMultiple epiphyseal dysplasiasXVIITransmembrane collagen in epidermal cellsQBenign atrophic generalized epidermolysis bullosaXV & XVIIIEndostatin-forming collagens, endothelial cellsQKnobloch syndrome (type XVIII collagen)
Type I
Type III
Type IV
Type V
Membrane Structure & Function