Chordae Tendinae
The chordae tendineae of the mitral valve function to transmit the
contractions of the papillary muscles to the leaflets of the MV complex.
They also serve to secure the leaflets to maintain valve closure and
prevent mitral valve prolapse. In order to perform these functions, the
chords must contain a high degree of elasticity, as well as considerable
strength and endurance. These chords are composed of collagen and
elastin fibers arranged in parallel. A study conducted by
Millington-Sanders et al.7 showed that the chordae
tendineae are composed of multiple layers of elastic fibers, an inner
collagen core, and an outer layer of endothelial cells (fig. 5). During
stretching, when papillary muscle contraction straightens the chords,
the collagenous wavy pattern disappears and transfers the peak stress
during contraction to the leaflets. The sleeve-shaped elastic network
that surrounds the internal collagen suggests that on relaxation of
tension, the elastic fibers would tend to restore the collagen to their
wavy configuration.