Kinetics of spermatogenesis in mammals: seminiferous epithelium cycle and spermatogonial renewal
Clermont, Y.
Physiological Reviews 52(1): 198-236
1972
ISSN/ISBN: 0031-9333 PMID: 4621362 DOI: 10.1152/physrev.1972.52.1.198Document Number: 488562
The length-tension relationship was determined for strips of guinea pig taenia coli and correlated with the length and ultrastructural organization of the component fibers. The mean fiber length in "stretched" strips (passive >/= active tension) was 30% greater than that for fibers in "unstretched" strips (active >> passive tension). In stretched fibers the dense bodies and 100 A diameter myofilaments were consolidated into a mass near the center of fibers in cross-sectional profile. The thick myofilaments were segregated into the periphery of the fiber profiles. In unstretched fibers the dense bodies-100 A diameter filaments and the thick myofilaments were uniformly distributed throughout cross-sectional profiles. A tentative model is proposed to account for the change in fiber length and ultrastructural organization that accompanies stretch. The basic features of the model require the dense bodies to be linked together into a network by the 100 A diameter filaments. The functional consequences of stretching the fibers are discussed in relation to the model proposed for this network.