麻省理工大学：《生物工程》教学讲义（英文版）lec 9

Values of the elastic or youngs modulus for naterials SILK F-ACTIN TUBULIN TENDON WOOD CONTRACTED~SKELETALMUSCLE 1.E+06 YMA FIBROBLAST CELLS 1E+02 ENOOIIHELIAL MPHOCYIES Muscle plasma LUMEN BLOOD Connective tissue Connective tissue Basal lamin thelial cell

1.E+00 1.E+02 1.E+04 1.E+06 1.E+08 1.E+10 1.E+12 DIAMOND STEEL BONE CONCRETE SILK F-ACTIN TENDON WOOD TUBULIN CONTRACTED SKELETAL MUSCLE ELASTIN RELAXED SKELETAL MUSCLE COLLAGEN GELS LUNG PARENCHYMA FIBROBLAST CELLS ENDOTHELIAL CELLS NEUTROPHILS LYMPHOCYTES various materials Values of the elastic or Young’s modulus for 1 Basal laminae (the yellow lines) are organized in three ways

Right tibia( somewhat non- isotropic and nonlinear) BA-direction Radial direction Comments bayashi K Tanabe Y, KO Anni Mech 4 human compact bone, Theor A Striated A-resting Microscopic B- max contraction sarcomere level 她时行苗m

Right tibia (somewhat non￾isotropic and nonlinear) Longitudinal direction Radial direction Microscopic - sarcomere level Striated muscle Macroscopic view A - resting B - max contraction C - active component 2

molecule with an optical tweezer -rap center XY stage Laser light The force-extension curve of a single collagen ll 50100150200150300 Extensions(nm) Table 22-4. Major Collagen Molecules Type Molecule Composition Structural features Ial(Dl[a2(D1 300-nm-long fibrils Skin tendon bone ligaments, dentin. 300-mmm long fibrils Le, vireou 00-lnm-long fibrils: often Skin, muscle blood v Ial(v)l 390-pm-long fibrils with vi [a levI a(VI) Lateral association with type Most mt Ix [aI(LX)Il a2(x)ll a 3(Ix)| Lateral association with type Cartilage. humor iy la lvillazavol Two-dimensional network All basal laminae SOURCE: K Kuhn, 1987, in R. Mayne and R Burgeson, eds, Strcture and Functi Collagen Types. Academic Press, P. 2: M van der Res and R. Garrone. 1991

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Image removed due to copyright considerations See Figure 19-41 in: Alberts, Bruce, et al. Molecular Biology of the Cell. 4th ed. New York: Garland Image may be viewed online at the NIH's PubMed Bookshelf. http://www.ncbi.nim.nihgov/entrez/query.fcgi?db=books 1 synthesis of pro-a chain Sell-assembly of three ER/Golgi Compartmen Collagen fibril 一→0 Secretory vesicle eps y and g are now thought to occur traceMtany, at least a some tissues. Events involved in the formation of a collagen fibril

4 Image removed due to copyright considerations. See Figure 19-41 in: Alberts, Bruce, et al. Molecular Biology of the Cell. 4th ed. New York: Garland Publishing, 2002. Image may be viewed online at the NIH's PubMed Bookshelf. Events involved in the formation of a collagen fibril. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=Books

Image removed due to copyright considerations. See Figure 7.3: 4 in: Fung, Y C. Biomechanics: Mechanical Properties of Living Tissues. New York: Springer-Verlag, 1993 Ice fibrils Light staining region Gap between individual with no gaps molecule Heavy metal stain

5 Image removed due to copyright considerations. See Figure 7.3:4 in: Fung, Y. C. Biomechanics: Mechanical Properties of Living Tissues. New York: Springer-Verlag, 1993. Striated appearance of collagen fibrils

and comea with alternating direction Image removed due to copyright considerations. See Figure 19-46 in: Alberts, Bruce, et al. Molecular Biology of the Cell. 4th ed. New York: Garland Publishing, 2002 Image may be viewed online at the NIh's PubMed Bookshelf. http://www.ncbinim.nihgov/entrez/query.fcgi?db-=books Type IX collagen molecule Fibril of type II collagen

Collagen fiber arrangement in skin and cornea with alternating directions 6 Image removed due to copyright considerations. See Figure 19-46 in: Alberts, Bruce, et al. Molecular Biology of the Cell. 4th ed. New York: Garland Publishing, 2002. Image may be viewed online at the NIH's PubMed Bookshelf. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=Books

Tendon Hierarch Evidence x-fay M 35 A staining periodicity fibroblasts waveform or crimp structure fascicular 15A35A100-200A500.5000A50-300μ 100-500μ ze Sc ACL- different strain rates Medium Range of linearity. E=d(stress)(strain)=10Pa Comments Ninety percent of the ACL specimens failed by avulsion at the insertion site(72% at the tibial insertion and 18% at the femoral insertion), and 10% failed in the midsubstance Reference(s) anto MI. Woo SL- Y(1993)The mechanical properties of skeletally mature rabbit antenor cruciate ligament and patellar tendon over a range of strain rates. J Orthop Res 11: 58-67 (with permission

ACL -- different strain rates Range of linearity. E = d(stress)/d(strain) = 109 Pa 7

Collagen derives its stiffness, not from the single molecule characteristics of collagen but rather from the straightening of“wavy” collagen fibe Co Johnson. J Ruberti

Collagen derives its stiffness, not from the single molecule characteristics of collagen, but rather from the straightening Cornea, M. Johnson, J. Ruberti of “wavy” collagen fibers 8 Image removed due to copyright considerations