The structure and development of avian lumbosacral specializations of the vertebral canal and the spinal cord with special reference to a possible function as a sense organ of equilibrium
The structure and development of avian lumbosacral specializations of the vertebral canal and the spinal cord with special reference to a possible function as a sense organ of equilibrium
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DOI：
10.1007/s00429-005-0016-6
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发表时间：
2005-08-01
期刊：
影响因子：
--
通讯作者：
Necker, R
中科院分区：
文献类型：
--
作者：
Necker, R
鸟类的腰椎和脊髓表现出许多特化，最近被解释为平衡的感觉器官。这种感觉器官被认为支持在地面上平衡行走。尽管大多数特殊的结构以前已经描述过了，但有必要重新评估作为感觉器官的可能功能的专门化。对成年鸽子进行了详细的特化研究。对该系统在鸽子(孵化时为半早熟)和鸡(早熟)的发育进行了研究。椎管的特化包括相当大的扩大，这不是由于脊神经组织的大小增加，而是由于背方窦内嵌有一个大的糖原体。椎管后壁呈节段性双侧背侧沟，向椎管腔方向被脑膜覆盖，在中线和外侧留下开口。这就形成了一个腰骶管系统，它的外观和功能与内耳的半规管相似。从侧面看，这些管道开口于脊髓腹侧突起或含有神经元的副叶上方。副叶外侧和腹侧有大的蛛网膜下腔脑脊液。这种液体的运动被认为是对肺叶的机械刺激。至于禽类腰骶特化的发展，主要关注的是肺叶和包括背管在内的邻近液体空间的组织。在鸽子中，这个系统在孵化时远不是成虫那样的，而是在孵化后迅速成熟。在鸡身上，这个系统在孵化时看起来已经是成年人的样子了。文中还讨论了结构发现所产生的含义，即腰臀特化作为平衡感觉器官的可能功能。新孵化的鸡的成体样组织在孵化后立即四处走动，支持作为参与地面运动控制的感觉器官的假定功能。
The avian lumbosacral vertebral column and spinal cord show a number of specializations which have recently been interpreted as a sense organ of equilibrium. This sense organ is thought to support balanced walking on the ground. Although most of the peculiar structures have been described previously, there was a need to reevaluate the specializations with regard to the possible function as a sense organ. Specializations were studied in detail in the adult pigeon. The development of the system was studied both in the pigeon (semiprecocial at hatching) and in the chicken (precocial). Specializations in the vertebral canal consist of a considerable enlargement, which is not due to an increase in the size of the spinal nervous tissue, but to a large glycogen body embedded in a dorsal rhomboid sinus. The dorsal wall of the vertebral canal shows segmented bilateral dorsal grooves, which are covered by the meninges towards the lumen of the vertebral canal leaving openings in the midline and laterally. This results in a system of lumbosacral canals which look and may function similar to the semicircular canals in the inner ear. Laterally these canals open above ventrolateral protrusions or accessory lobes of the spinal cord which contain neurons. There are large subarachnoidal cerebrospinal fluid spaces, lateral and ventral to the accessory lobes. Movement of this fluid is thought to stimulate the lobes mechanically. As to the development of avian lumbosacral specializations, main attention was given to the organization of the lobes and the adjacent fluid spaces including the dorsal canals. In the pigeon the system is far from being adult-like at hatching but maturates rapidly after hatching. In the chicken the system looks already adult-like at hatching. The implications derived from the structural findings are discussed with regard to a possible function of the lumbosacral specializations as a sense organ of equilibrium. The adult-like organization in the newly hatched chickens, which walk around immediately after hatching, supports the assumed function as a sense organ involved in the control of locomotion on the ground.