Structure Of Ligaments And Tendons Flashcards
What is the tensile strength of tendons?
Up to 1260kg/cm2
What do the crimping regions of ligaments allow? (Reference?)
Allow stretch
Resist against injury
(Frank, 2004)
Describe a collagen molecule
Smallest discernible unit of tendons and ligaments
Triple helix molecule
~1nm long
Mechanically resistant due to cross-linking
Multiple types
What do collagen molecules bind into and what length are they?
Fibrils
~100nm long
Collagen fibrils can be heterogenous in composition, give an example of what this means?
Type I fibrils have collagen types I, III, IV and IX
What constitutes a collagen fibre?
Collagen fibrils plus fibroblast cells producing ECM
How long is a collagen fibre?
~1-20microm
What are collagen fibres bundled into?
Subfascicles (primary bundle)
Fascicles (secondary bundle)
Tertiary bundles
How does crossing-over in tertiary collagen bundles affect the structure?
Results in higher tensile strength
What loose connective tissue structure surrounds each collagen fibre bundle (fascicles)?
Endotenon
Endoligament
What connective tissue structure surrounds groups of fascicles?
Epitenon
Epiligament
What cells are ligaments rich in?
Proprioceptive
What is the reference for the collagen organisation of tendons and ligaments?
Wang, 2006
In what orientations do the fibrils of elongated fibroblast cells run in in tendons and ligaments?
Longitudinally
Transversely
Horizontally
In what orientation do bundles of collagen fibres run?
Longitudinally
But not always parallel = Crossing over
How do the orientation of collagen fibrils and bundles affect function? (Reference?)
Serves to buffer against forces acting on these tissues from different directions
(Kannus, 2000)
How can the structure of tendons under higher strains be described?
Thicker
Shorter
Bigger and denser packed bundles
How can the structure of tendons under low strains be described and how does this affect the movements they are parts of?
Longer
Thinner
Used in more precise movements
What is an epitenon/epiligament?
Loose connective tissue sac acting as a supporting sheath and fill with synovial fluid
What is paratenon? What is its function?
The very outer layer Loose mesenchyme which carries: - Blood vessels - Lymphatics - Nerves Also assists in sliding
How much water is in the ECM of ligaments and how much in tendons?
60-80% water in ECM of both
How can the elasticity of both ligaments and tendons be described?
Ligaments = Stretchy Tendons = Rigid
What is the level of organisation of collagen fibres in both ligaments and tendons?
Ligaments = Less organised fibres Tendons = Highly organised fibres
What type(s) of collagen are present in both ligaments and tendons? (Reference?)
Ligaments = Type I most common but also Type III (Frank, 2004) Tendons = Type I collagen chiefly (Kannus, 2000)