Alice and David Jurist Institute for Biomedical Research, Hackensack University Medical Center, Hackensack, New Jersey.
Anat Rec (Hoboken). 2013 Oct;296(10):1615-27. doi: 10.1002/ar.22755. Epub 2013 Aug 9.
Little is known about the specializations of human tongue muscles. In this study, myofibrillar adenosine triphosphatase (mATPase) histochemical staining was used to study the percentage and distribution of slow twitch muscle fibers (slow MFs) within tongue muscles of four neurologically normal human adults and specimens from a 2-year-old human, a newborn human, an adult with idiopathic Parkinson's disease (IPD), and a macaque monkey. The average percentage of slow MFs in adult and the 2-year-old muscle specimens was 54%, the IPD was 45%, while the neonatal human (32%) and macaque monkey (28%) had markedly fewer slow MFs. In contrast, the tongue muscles of the rat and cat have been reported to have no slow MFs. There was a marked spatial gradient in the distribution of slow MFs with the highest percentages found medially and posteriorly. Normal adult tongue muscles were found to have a variety of uniquely specialized features including MF-type grouping (usually found in neuromuscular disorders), large amounts of loose connective tissue, and short branching MFs. In summary, normal adult human tongue muscles have by far the highest proportion of slow MFs of any mammalian tongue studied to date. Moreover, adult human tongue muscles have multiple unique anatomic features. As the tongue shape changes that are seen during speech articulation are unique to humans, we hypothesize that the large proportion of slow MFs and the anatomical specializations observed in the adult human tongue have evolved to perform these movements.
关于人类舌肌的特化功能知之甚少。在本研究中，使用肌球蛋白三磷酸腺苷酶（mATPase）组织化学染色来研究 4 位神经正常的成年人和 1 名 2 岁、1 名新生儿、1 名特发性帕金森病（IPD）成年患者以及 1 只猕猴的舌肌中慢收缩肌纤维（slow MFs）的比例和分布。成年和 2 岁肌肉标本中的 slow MFs 平均比例为 54%，IPD 为 45%，而新生儿（32%）和猕猴（28%）的 slow MFs 明显较少。相比之下，鼠和猫的舌肌已被报道没有 slow MFs。slow MFs 的分布存在明显的空间梯度，其百分比在内侧和后侧最高。正常成人舌肌具有多种独特的特化特征，包括肌纤维型分组（通常在神经肌肉疾病中发现）、大量疏松结缔组织和短分支肌纤维。总之，正常成人舌肌中 slow MFs 的比例迄今为止是所有已研究哺乳动物舌中最高的。此外，成人舌肌具有多种独特的解剖特征。由于言语发音过程中舌形的变化是人类特有的，我们假设大量的 slow MFs 和在成人舌中观察到的解剖特化是为了执行这些运动而进化而来的。
