查看Ch14 The Autonomic Nervous System的源代码

=== 交感神经节前神经元起源于脊髓节段 T1 至 L3，与椎旁或椎前神经节中的节后神经元形成突触 ===
<b style=color:#0ae>Sympathetic preganglionic neurons originate from spinal segments T1 to L3 and synapse with postganglionic neurons in paravertebral or prevertebral ganglia</b>

<b style=color:#f80>Preganglionic Neurons</b> The cell bodies of preganglionic sympathetic motor neurons are located in the thoracic and upper lumbar spinal cord between levels T1 and L3. At these spinal levels, autonomic neurons lie in the intermediolateral cell column, or lateral horn, between the dorsal and ventral horns (Fig. 14-2). Axons from preganglionic sympathetic neurons exit the spinal cord through the ventral roots along with axons from somatic motor neurons. After entering the spinal nerves, sympathetic efferents diverge from somatic motor axons to enter the white rami communicantes. These rami, or branches, are white because most preganglionic sympathetic axons are myelinated.

<b style=color:#f80>节前神经元</b> 节前交感神经运动神经元的细胞体位于 T1 和 L3 水平之间的胸椎和上腰椎脊髓中。在这些脊柱水平上，自主神经元位于背角和腹角之间的中间外侧细胞柱或外侧角中（图 14-2）。来自节前交感神经元的轴突与来自体细胞运动神经元的轴突一起通过腹根离开脊髓。进入脊神经后，交感神经传出物从躯体运动轴突分化进入白色支交通。这些支或分支是白色的，因为大多数节前交感神经轴突都是有髓的。

<b style=color:#f80>Paravertebral Ganglia</b> Axons from preganglionic neurons enter the nearest sympathetic paravertebral ganglion through a white ramus. These ganglia lie adjacent to the vertebral column. Although preganglionic sympathetic fibers emerge only from levels T1 to L3, the chain of sympathetic ganglia extends all the way from the upper part of the neck to the coccyx, where the left and right sympathetic chains merge in the midline and form the coccygeal ganglion. In general, one ganglion is positioned at the level of each spinal root, but adjacent ganglia are fused in some cases. The most rostral ganglion, the superior cervical ganglion, arises from fusion of C1 to C4 and supplies the head and neck. The next two ganglia are the middle cervical ganglion, which arises from fusion of C5 and C6, and the inferior cervical ganglion (C7 and C8), which is usually fused with the first thoracic ganglion to form the stellate ganglion. Together, the middle cervical and stellate ganglia, along with the upper thoracic ganglia, innervate the heart, lungs, and bronchi. The remaining paravertebral ganglia supply organs and portions of the body wall in a segmental fashion.

<b style=color:#f80>椎旁神经节</b> 来自节前神经元的轴突通过白色支进入最近的交感椎旁神经节。这些神经节位于脊柱附近。虽然节前交感神经纤维仅出现在 T1 至 L3 水平，但交感神经节链从颈部上部一直延伸到尾骨，左右交感神经链在中线汇合，形成尾骨神经节。一般来说，一个神经节位于每个脊髓根的水平，但在某些情况下，相邻的神经节会融合。最前端的神经节，即颈上神经节，由 C1 和 C4 融合产生，供应头部和颈部。接下来的两个神经节是颈中神经节，它是由 C5 和 C6 融合产生的，以及下颈神经节（C7 和 C8），通常与第一胸神经节融合形成星状神经节。中颈神经节和星状神经节以及上胸神经节一起支配心脏、肺和支气管。剩余的椎旁神经节以节段方式供应器官和体壁的一部分。


After entering a paravertebral ganglion, a preganglionic sympathetic axon has one or more of three fates. It may (1) synapse within that segmental paravertebral ganglion, (2) travel up or down the sympathetic chain to synapse within a neighboring paravertebral ganglion, or (3) enter the greater or lesser splanchnic nerve to synapse within one of the ganglia of the prevertebral plexus.

进入椎旁神经节后，节前交感神经轴突具有三种命运中的一种或多种。它可能 （1） 在该节段性椎旁神经节内形成突触，（2） 沿交感神经链向上或向下移动到邻近椎旁神经节内的突触，或 （3） 进入较大或较小的内脏神经到椎前丛神经节之一内的突触。

<b style=color:#f80>Prevertebral Ganglia</b> The prevertebral plexus lies in front of the aorta and along its major arterial branches and includes the prevertebral ganglia and interconnected fibers (Fig. 14-3). The major prevertebral ganglia are named according to the arteries that they are adjacent to and include the celiac, superior mesenteric, aorticorenal, and inferior mesenteric ganglia. Portions of the prevertebral plexus extend down the major arteries and contain other named and unnamed ganglia and plexuses of nerve fibers, which altogether make up a dense and extensive network of sympathetic neuron cell bodies and nerve fibers.

<b style=color:#f80>椎前神经节</b> 椎前丛位于主动脉前方及其主要动脉分支，包括椎前神经节和互连的纤维（图 14-3）。主要椎前神经节根据它们相邻的动脉命名，包括腹腔、肠系膜上神经节、主动脉核心神经节和肠系膜下神经节。椎前丛的一部分向下延伸到主要动脉，并包含其他命名和未命名的神经节和神经丛，它们共同构成了交感神经元细胞体和神经纤维的密集而广泛的网络。


Each preganglionic sympathetic fiber synapses on many postganglionic sympathetic neurons that are located within one or several nearby paravertebral or prevertebral ganglia. It has been estimated that each preganglionic sympathetic neuron branches and synapses on as many as 200 postganglionic neurons, which enables the sympathetic output to have more widespread effects. However, any impulse arriving at its target end organ has only crossed a single synapse between the preganglionic and postganglionic sympathetic neurons.

每个节前交感神经纤维突触位于位于附近一个或多个椎旁神经节或椎前神经节内的许多节后交感神经元上。据估计，每个节前交感神经元在多达 200 个节后神经元上分支和突触，这使得交感神经输出能够产生更广泛的影响。然而，任何到达其目标终末器官的冲动都只穿过了节前和节后交感神经元之间的单个突触。

<b style=color:#f80>Postganglionic Neurons</b> The cell bodies of postganglionic sympathetic neurons that are located within paravertebral ganglia send out their axons through the nearest gray rami communicantes, which rejoin the spinal nerves (see Fig. 14-2). These rami are gray because most postganglionic axons are unmyelinated. Because preganglionic sympathetic neurons are located only in the thoracic and upper lumbar spinal segments (T1 to L3), white rami are found only at these levels (Fig. 14-4, left panel). However, because each sympathetic ganglion sends out postganglionic axons, gray rami are present at all spinal levels from C2 or C3 to the coccyx. Postganglionic sympathetic axons from paravertebral and prevertebral ganglia travel to their target organs within other nerves or by traveling along blood vessels. Because the paravertebral and prevertebral sympathetic ganglia lie near the spinal cord and thus relatively far from their target organs, the postganglionic axons of the sympathetic division tend to be long. On their way to reach their targets, some postganglionic sympathetic axons travel through parasympathetic terminal ganglia or cranial nerve ganglia without synapsing[N14-2].

<b style=color:#f80>节后神经元</b> 位于椎旁神经节内的节后交感神经元的细胞体通过最近的灰色交感支发出轴突，这些支重新加入脊神经（见图 14-2）。这些支是灰色的，因为大多数节后轴突是无髓的。因为节前交感神经元仅位于胸椎和上腰椎段（T1 到 L3），所以白色支仅在这些水平上发现（图 14-4，左图）。然而，由于每个交感神经节都会发出节后轴突，因此从 C2 或 C3 到尾骨的所有脊柱水平都存在灰色支。来自椎旁和椎前神经节的节后交感神经轴突通过其他神经或沿血管行进到其目标器官。因为椎旁和椎前交感神经节位于脊髓附近，因此离它们的目标器官相对较远，所以交感神经支的节后轴突往往很长。在到达目标的途中，一些节后交感神经轴突穿过副交感神经末梢神经节或颅神经节，没有突触[N14-2]。


Parasympathetic preganglionic neurons originate from the brainstem and sacral spinal cord and synapse with postganglionic neurons in ganglia located near target organs

副交感神经节前神经元起源于脑干和骶脊髓，与位于靶器官附近神经节的节后神经元形成突触

The cell bodies of preganglionic parasympathetic neurons are located in the medulla, pons, and midbrain and in the S2 through S4 levels of the spinal cord (see Fig. 14-4, right panel). Thus, unlike the sympathetic— or thoracolumbar—division, whose preganglionic cell bodies are in the thoracic and lumbar spinal cord, the parasympathetic—or craniosacral—division’s preganglionic cell bodies are cranial and sacral. The preganglionic parasympathetic fibers originating in the brain distribute with four cranial nerves: the oculomotor nerve (CN III), the facial nerve (CN VII), the glossopharyngeal nerve (CN IX), and the vagus nerve (CN X). The preganglionic parasympathetic fibers originating in S2 through S4 distribute with the pelvic splanchnic nerves.

节前副交感神经元的细胞体位于延髓、脑桥和中脑以及脊髓的 S2 至 S4 水平（见图 14-4，右图）。因此，与交感神经或胸腰椎支不同，其节前细胞体位于胸腰脊髓中，副交感神经或颅骶支的节前细胞体是颅骨和骶骨。起源于大脑的节前副交感神经纤维分布有四条颅神经：动眼神经 （CN III）、面神经 （CN VII）、舌咽神经 （CN IX） 和迷走神经 （CN X）。起源于 S2 至 S4 的节前副交感神经纤维与盆腔内脏神经分布。


Postganglionic parasympathetic neurons are located in terminal ganglia that are more peripherally located and more widely distributed than are the sympathetic ganglia. Terminal ganglia often lie within the walls of their target organs. Thus, in contrast to the sympathetic division, postganglionic fibers of the parasympathetic division are short.In some cases, individual postganglionic parasympathetic neurons are found in isolation or in scattered cell groups rather than in encapsulated ganglia. 

节后副交感神经元位于末端神经节中，与交感神经节相比，末端神经节的位置更外围，分布更广泛。末端神经节通常位于其靶器官的壁内。因此，与交感神经支相反，副交感神经支的节后纤维很短。在某些情况下，单个节后副交感神经元孤立或分散在细胞群中，而不是在包膜神经节中发现。


<b style=color:#f80>Cranial Nerves III, VII, and IX</b> The preganglionic parasympathetic neurons that are distributed with CN III, CN VII, and CN IX originate in three groups of nuclei.

<b style=color:#f80>颅神经 III、VII 和 IX</b> 与 CN III、CN VII 和 CN IX 分布的节前副交感神经元起源于三组核。


1. The Edinger-Westphal nucleus is a subnucleus of the oculomotor complex in the midbrain (Fig. 14-5). Parasympathetic neurons in this nucleus travel in the oculomotor nerve (CN III) and synapse onto postganglionic neurons in the ciliary ganglion (see Fig. 14-4, right panel). The postganglionic fibers project to two smooth muscles of the eye: the constrictor muscle of the pupil and the ciliary muscle, which controls the shape of the lens (see Fig. 15-6).

1. Edinger-Westphal 核是中脑动眼神经复合体的亚核（图 14-5）。该核中的副交感神经元在动眼神经 （CN III） 中移动，并突触到达睫状神经节中的节后神经元（见图 14-4，右图）。节后纤维投射到眼睛的两块平滑肌：瞳孔收缩肌和睫状肌，它控制晶状体的形状（见图 15-6）。

2. The superior salivatory nucleus is in the rostral medulla (see Fig. 14-5) and contains parasympathetic neurons that project, through a branch of the facial nerve (CN VII), to the pterygopalatine ganglion (see Fig. 14-4, right panel). The postganglionic fibers supply the lacrimal glands, which produce tears. Another branch of the facial nerve carries preganglionic fibers to the submandibular ganglion. The postganglionic fibers supply two salivary glands, the submandibular and sublingual glands.

2. 上唾液核位于延髓喙部（见图 14-5），包含副交感神经元，这些神经元通过面神经的一个分支 （CN VII） 投射到翼腭神经节（见图 14-4，右图）。节后纤维供应泪腺，泪腺产生撕裂。面神经的另一个分支将节前纤维输送到下颌下神经节。节后纤维供应两个唾液腺，即下颌下腺和舌下腺。


3. The inferior salivatory nucleus and the rostral part of the nucleus ambiguus in the rostral medulla (see Fig. 14-5) contain parasympathetic neurons that project through the glossopharyngeal nerve (CN IX) to the otic ganglion (see Fig. 14-4, right panel). The postganglionic fibers supply a third salivary gland, the parotid gland.

3. 喙延髓中下唾液核和模糊核的喙部（见图 14-5）包含通过舌咽神经 （CN IX） 投射到耳神经节的副交感神经元（见图 14-4，右图）。节后纤维供应第三个唾液腺，即腮腺。


<b style=color:#f80>Cranial Nerve X</b> Most parasympathetic output occurs through the vagus nerve (CN X). Cell bodies of vagal preganglionic parasympathetic neurons are found in the medulla within the nucleus ambiguus and the dorsal motor nucleus of the vagus (see Fig. 14-5). This nerve supplies parasympathetic innervation to all the viscera of the thorax and abdomen, including the GI tract between the pharynx and distal end of the colon (see Fig. 14-4, right panel). Among other effects, electrical stimulation of the nucleus ambiguus results in contraction of striated muscle in the pharynx, larynx, and upper esophagus due to activation of somatic motor neurons (not autonomic), as well as slowing of the heart due to activation of vagal preganglionic parasympathetic neurons. Stimulation of the dorsal motor nucleus of the vagus induces many effects in the viscera, including initiation of secretion of gastric acid, insulin, and glucagon. Preganglionic parasympathetic fibers of the vagus nerve join the esophageal, pulmonary, and cardiac plexuses and travel to terminal ganglia that are located within their target organs.

<b style=color:#f80>颅神经 X</b> 大多数副交感神经输出通过迷走神经 （CN X） 发生。迷走神经节前副交感神经元的细胞体位于迷走神经模糊核和背侧运动核内的延髓中（见图 14-5）。该神经为胸部和腹部的所有内脏提供副交感神经支配，包括咽部和结肠远端之间的胃肠道（见图 14-4，右图）。除其他作用外，由于体细胞运动神经元（非自主神经）的激活，对模糊核的电刺激导致咽部、喉部和食管上部的横纹肌收缩，以及由于迷走神经节前副交感神经元的激活而导致心脏减慢。刺激迷走神经背侧运动核在内脏中引起许多影响，包括开始分泌胃酸、胰岛素和胰高血糖素。迷走神经的节前副交感神经纤维加入食管丛、肺丛和心脏丛，并行进到位于其靶器官内的末端神经节。


<b style=color:#f80>Sacral Nerves</b> The cell bodies of preganglionic parasympathetic neurons in the sacral spinal cord (S2 to S4) are located in a position similar to that of the preganglionic sympathetic neurons—although they do not form a distinct intermediolateral column. Their axons leave through ventral roots and travel with the pelvic splanchnic nerves to their terminal ganglia in the descending colon and rectum (see p. 862), as well as to the bladder (see pp. 736–737) and the reproductive organs of the male (see p. 1104) and female (see p. 1127).

<b style=color:#f80>骶神经</b> 骶脊髓（S2 至 S4）中节前副交感神经元的细胞体位于与节前交感神经元相似的位置——尽管它们不形成明显的中间外侧柱。它们的轴突从腹根离开，与盆腔内脏神经一起移动到降结肠和直肠的末端神经节（见第 862 页），以及膀胱（见第 736-737 页）和男性（见第 1104 页）和女性（见第 1127 页）的生殖器官。

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