查看Ch14 The Autonomic Nervous System的源代码

=== 肠部是胃肠道的一个自给自足的神经系统，接收交感神经和副交感神经的输入 ===
<b style=color:#0ae>The enteric division is a self-contained nervous system of the GI tract and receives sympathetic and parasympathetic input</b>

The enteric nervous system (ENS) is a collection of nerve plexuses that surround the GI tract, including the pancreas and biliary system. Although it is entirely peripheral, the ENS receives input from the sympathetic and parasympathetic divisions of the ANS. The ENS is estimated to contain >100 million neurons, including afferent neurons, interneurons, and efferent postganglionic parasympathetic neurons. Enteric neurons contain many different neurotransmitters and neuromodulators. Thus, not only does the total number of neurons in the enteric division exceed that of the spinal cord, but the neurochemical complexity of the ENS also approaches that of the CNS. The anatomy of the ENS as well as its role in controlling GI function is discussed in Chapter 41.

肠道神经系统 （ENS） 是围绕胃肠道的神经丛的集合，包括胰腺和胆道系统。虽然它完全是外围的，但 ENS 接收来自 ANS 的交感神经和副交感神经部门的输入。据估计，ENS 包含 > 1 亿个神经元，包括传入神经元、中间神经元和传出节后副交感神经元。肠道神经元包含许多不同的神经递质和神经调节剂。因此，不仅肠道分裂的神经元总数超过脊髓的神经元总数，而且 ENS 的神经化学复杂性也接近 CNS 的神经化学复杂性。ENS 的解剖结构及其在控制 GI 功能中的作用将在第 41 章中讨论。


The plexuses of the ENS are a system of ganglia sandwiched between the layers of the gut and connected by a dense meshwork of nerve fibers. The myenteric or Auerbach’s plexus (Fig. 14-6) lies between the outer longitudinal and the inner circular layers of smooth muscle, whereas the submucosal or Meissner’s plexus lies between the inner circular layer of smooth muscle and the most internal layer of smooth muscle, the muscularis mucosae (see Fig. 41-3). In the intestinal wall, the myenteric plexus is involved primarily in the control of motility, whereas the submucosal plexus is involved in the control of ion and fluid transport. Both the myenteric and the submucosal plexuses receive preganglionic parasympathetic innervation from the vagus nerve (or sacral nerves in the case of the distal portion of colon and rectum). Thus, in one sense, the enteric division is homologous to a large and complex parasympathetic terminal ganglion. The other major input to the ENS is from postganglionic sympathetic neurons. Thus, the ENS can be thought of as “postganglionic” or as a “terminal organ” with respect to the parasympathetic division and “post-postganglionic” with respect to the sympathetic division. Input from both the sympathetic and parasympathetic divisions modulates the activity of the ENS, but the ENS can by and large function normally without extrinsic input. The isolated ENS can respond appropriately to local stimuli and control most aspects of gut function, including initiating peristaltic activity in response to gastric distention, controlling secretory and absorptive functions, and triggering biliary contractions (Box 14-1).

ENS 的神经丛是夹在肠道各层之间的神经节系统，由密集的神经纤维网连接。肌间神经丛或 Auerbach 神经丛（图 14-6）位于平滑肌的外纵层和内环层之间，而粘膜下神经丛或 Meissner 神经丛位于平滑肌的内环层和平滑肌最内层之间，即粘膜肌层（见图 41-3）。在肠壁中，肌间神经丛主要参与运动的控制，而粘膜下丛则参与离子和液体运输的控制。肌间神经丛和粘膜下丛都接受来自迷走神经（或结肠和直肠远端部分的骶神经）的节前副交感神经支配。因此，从某种意义上说，肠道支与一个大而复杂的副交感神经末末节同源。ENS 的另一个主要输入来自节后交感神经元。因此，ENS 可以被认为是“神经节后”或“终末器官”，而对于交感神经分支，可以认为是“神经节后”。来自交感神经和副交感神经部门的输入都调节了 ENS 的活动，但 ENS 基本上可以在没有外源输入的情况下正常运作。离体 ENS 可以对局部刺激做出适当反应并控制肠道功能的大多数方面，包括启动蠕动活动以响应胃膨胀、控制分泌和吸收功能以及触发胆道收缩（框 14-1）。

<br>