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Quadrupedal Mechanics - Anatomy & Physiology (view source)
Revision as of 00:57, 27 April 2013
, 00:57, 27 April 2013→2 Elasticity: external forces and stored energy
[[File:QMSection2.9.png|thumb|'''Fig. 2.9 Collagen structure, viewed electron-microscopically''' ]]
[[File:QMSection2.9.png|thumb|'''Fig. 2.9 Collagen structure, viewed electron-microscopically''' ]]
'''Collagen molecules, fibrils and fibres'''
Collagen fibrils are formed when three tropocollagen molecules, each consisting of three helically arranged polypeptide chains 280 nm long, coil helically together, and align with other such "super helices". These polymeric molecules each overlap about one quarter of their length, so that an axial periodicity of 60-70 nm is visible with the electron microscope (Fig. 2.9). A collagen fibre is formed from bundles of fibrils (Fig. 2.8). Single collagen fibres are visible with the light microscope in connective tissues. They accumulate in bundles or sheets to form the gross structures ligaments, tendons and fasciae.
::'''Fig. 2.9 Collagen structure, viewed electron-microscopically'''
::'''Fig. 2.9 Collagen structure, viewed electron-microscopically'''
::• collagen fibrils sectioned transversely
::• collagen fibrils sectioned transversely
::(from Deane, Massey thesis, 1991).
::(from Deane, Massey thesis, 1991).