Unformatted text preview: Harvard-MIT Division of Health Sciences and Technology HST.523J: Cell-Matrix Mechanics Prof. Myron Spector Massachusetts Institute of Technology Massachusetts Harvard Medical School Brigham and Women’s Hospital VA Boston Healthcare System 2.785j/3.97J/BEH.411/HST523J EXTRACELLULAR MATRIX MOLECULES M. Spector, Ph.D. and I.V. Yannas, Ph.D. MECHANICAL BEHAVIOR OF TISSUE MECHANICAL Determined by: Molecule structure (nm scale) Matrix architecture (µm)
Including porosity Which matrix molecules present Organization of the molecules Tissue size and shape (mm, cm)
Including composite structure comprising Including various architectural units various Bone Diagrams and photo of bone structure removed for copyright reasons. Cancellous (trabecular) bone Cortical bone EXTRACELLULAR MATRIX MOLECULES MOLECULES The principal structural matrix molecules are: The collagen, proteoglycan, and elastin. collagen, Adhesion proteins are also important matrix Adhesion molecules (including fibronectin and laminin) laminin Water can also be considered as a matrix Water molecule contributing to the mechanical behavior of the tissue COLLAGENS COLLAGENS
More than 20 distinct collagens have been identified and More each is encoded by a different gene. each
Combinations of these genes are expressed in different tissues. Combinations The main types of collagen in connective tissues are types I, II, III, V, and IX.
Type I is the principal collagen of skin and bone and, by far, the Type he most abundant in the body (representing 90 per cent of body collagen). collagen). Type II is found in the cartilage. Type III is found in skin, blood vessels and internal organs. Type V is found in bone, skin, tendons, ligaments, and cornea. Types IV and VIII are network-forming collagens which forming polymerize to form the sheet-like basement membrane . polymerize References
Images removed for copyright reasons. Sources: American Academy of Orthopaedic Surgeons (AAOS). “Orthopaedic Basic Science Slide Set,” CD-ROM, 2nd ed., 1999. Diagrams of articular cartilage, collagen structure, proteoglycan aggregate, pericellular matrix and intercellular matrix, and analysis of mechanical properties. So, C.L. et al. “Impact of mutations of cartilage matrix genes on matrix structure, gene activity and chondrogenesis.” Osteoarthritis and Cartilage 9A:S160 (2001) Figure by MIT OCW. After Fung. Figure by MIT OCW. ...
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- Spring '03
- Collagen, Extracellular matrix molecules, Prof. Myron Spector