查看Ch14 The Autonomic Nervous System的源代码

=== 各种脑干核提供对 ANS 的基本控制 ===
<b style=color:#0ae>A variety of brainstem nuclei provide basic control of the ANS</b>

In addition to nuclei that contain parasympathetic preganglionic neurons (see Fig. 14-5), a variety of other brainstem structures are also involved in visceral control. These structures include the nucleus tractus solitarii, area postrema, ventrolateral medulla, medullary raphé, reticular formation, locus coeruleus, and parabrachial nucleus. These nuclei within the lower part of the brainstem mediate autonomic reflexes, control specific autonomic functions, or modulate the general level of autonomic tone. In some cases, these nuclei play a well-defined role in one specific autonomic function. For example, stimulation of a group of neurons in the rostral portion of the ventrolateral medulla increases sympathetic output to the cardiovascular system—without affecting respiration or sympathetic output to other targets. In other cases, these nuclei are linked to more than one autonomic function. For example, the medullary raphé contains serotonergic neurons that project to cardiovascular, respiratory, and GI neurons, the reticular activating system, and pain pathways. Therefore, these neurons can affect the background level of autonomic tone. The specific functions of some nuclei are not known, and their involvement in autonomic control is inferred from their anatomical connections, a correlation between neuron activity and activity in autonomic nerves, or the effect of lesions.

除了包含副交感神经节前神经元的细胞核（见图 14-5）外，各种其他脑干结构也参与内脏控制。这些结构包括孤束核、极后区、腹外侧延髓、髓质、网状结构、蓝斑和臂旁核。这些位于脑干下部的细胞核介导自主神经反射，控制特定的自主神经功能，或调节自主神经张力的一般水平。在某些情况下，这些细胞核在一种特定的自主神经功能中发挥着明确的作用。例如，刺激腹外侧延髓喙部的一组神经元会增加心血管系统的交感神经输出，而不会影响呼吸或对其他靶标的交感神经输出。在其他情况下，这些细胞核与多个自主神经功能有关。例如，髓质包含血清素能神经元，这些神经元投射到心血管、呼吸和胃肠道神经元、网状激活系统和疼痛通路。因此，这些神经元可以影响自主神经音调的背景水平。一些细胞核的具体功能尚不清楚，它们参与自主神经控制的参与是从它们的解剖学联系、神经元活动与自主神经活动之间的相关性或病变的影响中推断出来的。


One of the most important lower brainstem structures is the nucleus tractus solitarii (NTS) in the medulla. The NTS contains second-order sensory neurons that receive all input from peripheral chemoreceptors (see pp. 710–713) and baroreceptors input (see p. 537), as well as non-nociceptive afferent input from every organ of the thorax and abdomen. Visceral afferents from the vagus nerve make their first synapse within the NTS, where they combine with other visceral (largely unconscious) afferent impulses derived from the glossopharyngeal (CN IX), facial (CN VII), and trigeminal (CN V) nerves. These visceral afferents form a large bundle of nerve fibers—the tractus solitarius—that the NTS surrounds. Afferent input is distributed to the NTS in a viscerotopic manner, with major subnuclei devoted to respiratory, cardiovascular, gustatory, and GI input. The NTS also receives input and sends output to many other CNS regions (Table 14-4), including the brainstem nuclei described above as well as the hypothalamus and the forebrain. These widespread interconnections allow the NTS to influence and to be influenced by a wide variety of CNS functions. Thus, the NTS is the major lower brainstem command center for visceral control. It integrates multiple inputs from visceral afferents and exerts control over autonomic output, thereby participating in autonomic reflexes that maintain the homeostasis of many basic visceral functions.

最重要的下脑干结构之一是延髓中的孤束核 （NTS）。NTS 包含二阶感觉神经元，它们接收来自外周化学感受器（见第 710-713 页）和压力感受器输入（见第 537 页）的所有输入，以及来自胸部和腹部每个器官的非伤害性传入输入。来自迷走神经的内脏传入神经在 NTS 内形成第一个突触，在那里它们与来自舌咽神经 （CN IX）、面部 （CN VII） 和三叉神经 （CN V） 的其他内脏（大部分是无意识的）传入冲动结合。这些内脏传入神经形成一大束神经纤维——孤立束——NTS 围绕着它。传入输入以内脏定向方式分布到 NTS，主要亚核专门用于呼吸、心血管、味觉和 GI 输入。NTS 还接收输入并将输出发送到许多其他 CNS 区域（表 14-4），包括上述脑干核以及下丘脑和前脑。这些广泛的互连使 NTS 能够影响各种 CNS 功能并受其影响。因此，NTS 是内脏控制的主要下脑干指挥中心。它整合了来自内脏传入神经的多个输入，并控制自主神经输出，从而参与维持许多基本内脏功能的稳态的自主神经反射。

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