Torrella J R, Fouces V, Palomeque J, Viscor G
Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Spain.
J Anat. 1998 Feb;192 ( Pt 2)(Pt 2):211-22. doi: 10.1046/j.1469-7580.1998.19220211.x.
Six muscles of the mallard duck (Anas platyrhynchos), the common coot (Fulica atra) and the yellow-legged gull (Larus cachinnans) were analysed morphometrically, with special emphasis on their functional implications and physiological needs. Oxidative fibres always had significantly smaller size than anaerobic fibres, although no differences in the number of capillaries per fibre were found. This resulted in greater capillary counts per unit of fibre area and perimeter in oxidative than anaerobic fibres, which indicates that the greater demand for oxygen supply may be achieved by decreasing the size of the muscle fibre rather than by increasing the number of associated capillaries. Fast oxidative fibres of the pectoralis and the triceps of the gull had greater sizes than the fast oxidative fibres of the mallard and the coot, which correlates with the difference in energetic demands between flapping and gliding flight. Greater fibre cross-sectional areas and perimeters seem suited to afford the long-lasting activity with low metabolic demands required during gliding. By contrast, mallards and coots attain a high oxidative metabolism, during sustained flapping flight, by reducing fibre size at the expense of a diminished ability for force generation. Between-species comparisons of the hindlimb muscles only yielded differences for the anaerobic fibres of the gastrocnemius, as an important adaptive response to force generation during burst locomotion. The need to manage sustained swimming abilities effectively may result in similar FOG fibre morphometry of the hindlimb muscles studied, indicating that a compromise between the oxygen flux to the muscle cell and the development of power is highly optimised in oxidative fibres of the bird species studied.
对绿头鸭（Anas platyrhynchos）、白骨顶鸡（Fulica atra）和黄腿鸥（Larus cachinnans）的六块肌肉进行了形态测量分析，特别强调了它们的功能含义和生理需求。氧化型纤维的尺寸总是显著小于无氧型纤维，尽管每根纤维的毛细血管数量没有差异。这导致氧化型纤维每单位纤维面积和周长的毛细血管数量比无氧型纤维更多，这表明对氧气供应的更大需求可能是通过减小肌肉纤维的尺寸而不是增加相关毛细血管的数量来实现的。鸥的胸肌和肱三头肌的快速氧化型纤维比绿头鸭和白骨顶鸡的快速氧化型纤维尺寸更大，这与扑翼飞行和滑翔飞行之间的能量需求差异相关。更大的纤维横截面积和周长似乎适合于在滑翔过程中提供所需的低代谢需求的持久活动。相比之下，绿头鸭和白骨顶鸡在持续扑翼飞行期间通过减小纤维尺寸来实现高氧化代谢，但代价是产生力量的能力下降。后肢肌肉的种间比较仅在腓肠肌的无氧型纤维方面产生差异，这是对爆发性运动中力量产生的一种重要适应性反应。有效管理持续游泳能力的需求可能导致所研究的后肢肌肉具有相似的快慢氧化型纤维形态测量结果，这表明在所研究的鸟类物种的氧化型纤维中，肌肉细胞的氧通量和力量发展之间的平衡得到了高度优化。
