Werth Alexander J, Lillie Margo A, Piscitelli Marina A, Wayne Vogl A, Shadwick Robert E
Department of Biology, Hampden-Sydney College, Hampden-Sydney, Virginia, 23943.
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
Anat Rec (Hoboken). 2019 May;302(5):735-744. doi: 10.1002/ar.24035. Epub 2018 Dec 8.
The tongue of rorqual (balaenopterid) whales slides far down the throat into the expanded oral pouch as an enormous mouthful of water is engulfed during gulp feeding. As the tongue and adjacent oral floor expands and slides caudoventrally, it glides along a more superficial (outer) layer of ventral body wall musculature, just deep to the accordion-like ventral throat pleats. We hypothesize that this sliding movement of adjacent musculature is facilitated by a slick, stretchy layer of loose areolar connective tissue that binds the muscle fibers and reduces friction: fascia. Gross anatomical examination of the gular region of adult minke, fin, and humpback whales confirms the presence of a discrete, three-layered sublingual fascia interposed between adhering fasciae of the tongue and body wall. Histological analysis of this sublingual fascia reveals collagen and elastin fibers loosely organized in a random feltwork along with numerous fibroblasts in a watery extracellular matrix. Biomechanical testing of tissue samples in the field and laboratory, via machine-controlled or manual stretching, demonstrates expansion of the sublingual fascia and its three layers up to 250% beyond resting dimensions, with slightly more extension observed in anteroposterior (rather than mediolateral or oblique) stretching, and with the most superficial of the fascia's three layers. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:735-744, 2019. © 2018 Wiley Periodicals, Inc.
须鲸在滤食时会大口吞下大量海水，此时它们的舌头会顺着喉咙向下滑入扩张的口腔袋中。随着舌头和相邻的口腔底部扩张并向尾腹侧滑动，它会沿着腹侧体壁肌肉组织的更浅（外层）层滑动，就在类似手风琴的腹侧喉部褶皱的深层。我们推测，相邻肌肉组织的这种滑动运动是由一层光滑、有弹性的疏松结缔组织促进的，该组织将肌肉纤维结合在一起并减少摩擦，即筋膜。对成年小须鲸、长须鲸和座头鲸喉部区域的大体解剖检查证实，在舌头和体壁的附着筋膜之间存在一层离散的三层舌下筋膜。对该舌下筋膜的组织学分析显示，胶原蛋白和弹性纤维在含水的细胞外基质中随机排列成松散的毡状网络，还有大量成纤维细胞。通过机器控制或手动拉伸对现场和实验室的组织样本进行生物力学测试表明，舌下筋膜及其三层可扩张至超出静止尺寸达250%，在前后向（而非内外侧或斜向）拉伸时观察到的伸展略多，且在筋膜的三层中最表层的伸展最多。《解剖学记录》，2018年。©2018威利期刊公司。《解剖学记录》，302:735 - 744，2019年。©2018威利期刊公司。
