The structure and function of normally mineralizing avian tendons.

Title

The structure and function of normally mineralizing avian tendons.

Creator

Landis William J; Silver Frederick H

Publisher

Comparative biochemistry and physiology. Part A, Molecular & integrative physiology

Date

2002
2002-12

Description

The leg tendons of certain avian species normally calcify. The gastrocnemius, or Achilles, tendon of the domestic turkey, Meleagris gallopavo, is one such example. Its structure and biomechanical properties have been studied to model the adaptive nature of this tendon to external forces, including the means by which mineral deposition occurs and the functional role mineralization may play in this tissue. Structurally, the distal rounded, thick gastrocnemius bifurcates into two smaller proximal segments that mineralize with time. Mineral deposition occurs at or near the bifurcation, proceeding in a distal-to-proximal direction along the segments toward caudal and medial muscle insertions of the bird hip. Mineral formation appears mediated first by extracellular matrix vesicles and later by type I collagen fibrils. Biomechanical analyses indicate lower tensile strength and moduli for the thick distal gastrocnemius compared to narrow, fan-shaped proximal segments. Tendon mineralization here appears to be strain-induced, the muscle forces causing matrix deformation leading conceptually to calcium binding through the exposure of charged groups on collagen, release of sequestered calcium by proteoglycans, and increased diffusion. Functionally, the mineralized tendons limit further tendon deformation, reduce tendon strain at a given stress, and provide greater load-bearing capacity to the tissue. They also serve as important and efficient elastic energy storage reservoirs, increasing the amount of stored elastic energy by preventing flexible type I collagen regions from stretching and preserving muscle energy during locomotion of the animals.

Subject

Animals; Biomechanical Phenomena; Birds/*anatomy & histology/*physiology; Minerals/*metabolism; Non-programmatic; Tendons/anatomy & histology/*cytology/*physiology

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

1135–1157

Issue

4

Volume

133

Citation

Landis William J; Silver Frederick H, “The structure and function of normally mineralizing avian tendons.,” NEOMED Bibliography Database, accessed March 5, 2021, https://neomed.omeka.net/items/show/3953.

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