Tendons Flashcards
Describe the properties of tendons
Highly specialized tissue constructed to take tensile force only
Stiff, elastic, tough
Made of aligned collagen fibers
What causes the toe and heel regions in the stress-strain curve of tendons?
Toe region - Straightening of crimps and soft proteoglycan matrix
Heel region - Molecular kink straightening
What are tendons are a composite of?
Collagen type I makes up >80% of the dry weight
Proteoglycans with a long hyaluronan molecule backbone, core proteins branch out with GAG side chains
GAG are extremely hydrophilic
What causes the spacing of spots on the diffraction pattern obtained from in situ x-ray imaging of tendons?
The D-band spacing structure of collagen
What happens during the linear region of the stress-strain curve of tendons?
Fibrils stretch and glide past each other in the linear region
Why don’t babies have strongly differentiated bones and tendons?
The bones haven’t mineralized enough yet
Why is it difficult to measure tendon fracture?
The crack doesn’t follow the intended path, delamination occurs, and crack blunting reduces the stress concentration at the notch
Requirements for interfaces in a unidirectional fiber composite
- Interfaces must be strong enough to transmit stresses from fiber to fiber
- Interfaces must be weak enough to deflect crack and enable crack bridging
How does crack deflection ideally occur in a tendon?
The crack spreads over the weaker interface and gets blunted while the intact fibers bridge the crack. Energy is dissipated by fiber debonding and friction.
