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Cervical Ganglia
The cervical ganglia are paravertebral ganglia of the sympathetic nervous system. Preganglionic nerves from the thoracic spinal cord enter into the cervical ganglions and synapse with its postganglionic fibers or nerves. The cervical ganglion has three paravertebral ganglia: * superior cervical ganglion (largest) – adjacent to C2 & C3; postganglionic axon projects to target: (heart, head, neck) via "hitchhiking" on the carotid arteries * middle cervical ganglion (smallest) – adjacent to C6; target: heart, neck * inferior cervical ganglion The inferior cervical ganglion is one of the three cervical sympathetic ganglia (i.e. of the cervical portion of the sympathetic trunk). It is situated between the base of the transverse process of the last cervical vertebra and the neck of the .... The inferior ganglion may be fused with the first thoracic ganglion to form a single structure, the stellate ganglion. – adjacent to C7; target: heart, lower neck, arm, posterior crani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paravertebral Ganglia
The sympathetic ganglia, or paravertebral ganglia, are autonomic ganglia of the sympathetic nervous system. Ganglia are 20,000 to 30,000 Afferent nerve fiber, afferent and Efferent nerve fiber, efferent nerve cell bodies that run along on either side of the spinal cord. Afferent nerve cell bodies bring information from the body to the brain and spinal cord, while efferent nerve cell bodies bring information from the brain and spinal cord to the rest of the body. The cell bodies create long sympathetic chains that are on either side of the spinal cord. They also form para- or pre-vertebral ganglia of gross anatomy. The efferent nerve cell bodies bring information from the body to the brain regarding perceptions of danger. This perception of danger can instigate the fight-or-flight response associated with the sympathetic nervous system. The fight-or-flight response is adaptive when there is a real and present danger which can be avoided or diminished through increased sympathetic ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympathetic Nervous System
The sympathetic nervous system (SNS or SANS, sympathetic autonomic nervous system, to differentiate it from the somatic nervous system) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system. The autonomic nervous system functions to regulate the body's unconscious actions. The sympathetic nervous system's primary process is to stimulate the body's fight or flight response. It is, however, constantly active at a basic level to maintain homeostasis. The sympathetic nervous system is described as being antagonistic to the parasympathetic nervous system. The latter stimulates the body to "feed and breed" and to (then) "rest-and-digest". The SNS has a major role in various physiological processes such as blood glucose levels, body temperature, cardiac output, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preganglionic Nerve Fibers
In the autonomic nervous system, nerve fibers from the central nervous system to the ganglion are known as preganglionic nerve fibers. All preganglionic fibers, whether they are in the sympathetic division or in the parasympathetic division, are cholinergic (that is, these fibers use acetylcholine as their neurotransmitter) and they are myelinated. Sympathetic preganglionic fibers tend to be shorter than parasympathetic preganglionic fibers because sympathetic ganglia are often closer to the spinal cord than are the parasympathetic ganglia. Another major difference between the two ANS (autonomic nervous systems) is divergence. Whereas in the parasympathetic division there is a divergence factor of roughly 1:4, in the sympathetic division there can be a divergence of up to 1:20. This is due to the number of synapses formed by the preganglionic fibers with ganglionic neurons. See also * Nerve fiber * Grey column * Terminal cisterna * Rexed lamina * Postganglionic nerve fib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postganglionic Nerve Fibers
In the autonomic nervous system, nerve fibers from the ganglion to the effector organ are called postganglionic nerve fibers. Neurotransmitters The neurotransmitters of postganglionic fibers differ: * In the parasympathetic division, neurons are ''cholinergic''. That is to say acetylcholine is the primary neurotransmitter responsible for the communication between neurons on the parasympathetic pathway. * In the sympathetic division, neurons are mostly ''adrenergic'' (that is, epinephrine and norepinephrine function as the primary neurotransmitters). Notable exceptions to this rule include the sympathetic innervation of sweat glands and arrectores pilorum muscles where the neurotransmitter at both pre and post ganglionic synapses is acetylcholine. Another notable structure is the medulla of the adrenal gland, where chromaffin cells function as modified post-ganglionic nerves. Instead of releasing epinephrine and norepinephrine into a synaptic cleft, these cells of the adrenal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Cervical Ganglion
The superior cervical ganglion (SCG) is the upper-most and largest of the cervical sympathetic ganglia of the sympathetic trunk. It probably formed by the union of four sympathetic ganglia of the cervical spinal nerves C1–C4. It is the only ganglion of the sympathetic nervous system that innervates the head and neck. The SCG innervates numerous structures of the head and neck. Structure The superior cervical ganglion is reddish-gray color, and usually shaped like a spindle with tapering ends. It measures about 3 cm in length. Sometimes the SCG is broad and flattened, and occasionally constricted at intervals. It formed by the coalescence of four ganglia, corresponding to the four upper-most cervical nerves C1–C4. The bodies of its preganglionic sympathetic afferent neurons are located in the lateral horn of the spinal cord. Their axons enter the SCG to synapse with postganglionic neurons whose axons then exit the rostral end of the SCG and proceed to innervate their targ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Cervical Ganglion
The middle cervical ganglion is the smallest of the three cervical sympathetic ganglia (i.e. of the cervical portion of the sympathetic trunk). It presumably represents the merging of the sympathetic ganglia of cervical segments C5–C6. It is usually situated at the level of the sixth cervical vertebra. Anatomy The middle cervical ganglion is presumed to represent the union of the two sympathetic ganglia corresponding to cervical segments C5–C6 since its gray rami communicantes usually join the cervical spinal nerves C5–C6, however, the ganglion sometimes also contributes gray rami communicantes to spinal nerves C4 and C7. Relations The ganglion is usually situated at the level of the sixth cervical vertebra, lying medial to its carotid tubercle. It is situated either anterior or superior to the inferior thyroid artery. It may adjoin the inferior cervical ganglion. Branches * Gray rami communicantes – join the anterior rami of the cervical nerves C5–C6, sometim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Cervical Ganglion
The inferior cervical ganglion is one of the three cervical sympathetic ganglia (i.e. of the cervical portion of the sympathetic trunk). It is situated between the base of the transverse process of the last cervical vertebra and the neck of the first rib, on the medial side of the costocervical artery. It is often united with the first (and sometimes the second) thoracic ganglion to form the cervicothoracic ganglion (stellate ganglion). Anatomy The inferior cervical ganglion is irregularly shaped. It is substantially larger than the middle cervical ganglion (but smaller than the superior cervical ganglion). As the sympathetic trunk curves posteriorly between the neck and thorax, this ganglion is oriented in a nearly anteroposterior axis. The ganglion is presumed to represent the union of the cervical segmental sympathetic ganglia C7-C8 and the thoracic segmental sympathetic ganglia T1, but sometimes up to T4 as well - the T1 ganglion may or may not be separate to leave a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracic Ganglion
The thoracic ganglia are paravertebral ganglia. The thoracic portion of the sympathetic trunk typically has 12 thoracic ganglia. Emerging from the ganglia are thoracic splanchnic nerves (the cardiopulmonary, the greater, lesser, and least splanchnic nerves) that help provide sympathetic innervation to thoracic and abdominal structures. The thoracic part of sympathetic trunk lies posterior to the costovertebral pleura and is hence not a content of the posterior mediastinum Also, the ganglia of the thoracic sympathetic trunk have both white and gray rami communicantes. The white rami communicantes carry sympathetic fibers arising in the spinal cord into the sympathetic trunk, while the gray rami communicantes carry postganglionic nerve fibers of the sympathetic nervous system back to the spinal nerves A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal ner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellate Ganglion
The stellate ganglion (or cervicothoracic ganglion) is a sympathetic ganglion formed by the fusion of the inferior cervical ganglion and the first thoracic (superior thoracic sympathetic) ganglion, which is present in 80% of individuals. Sometimes, the second and the third thoracic ganglia are included in this fusion. Anatomy The stellate ganglion is polygonal in shape (). It is relatively big compared to the much smaller thoracic, lumbar, and sacral ganglia. Relations Stellate ganglion is located at the level of C7, anterior to the transverse process of C7 and the neck of the first rib, superior to the cervical pleura and just below the subclavian artery. It is superiorly covered by the prevertebral lamina of the cervical fascia and anteriorly in relation with common carotid artery, subclavian artery and the beginning of vertebral artery which sometimes leaves a groove at the apex of this ganglion (this groove can sometimes even separate the stellate ganglion into so call ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Plexus
The cardiac plexus is a plexus of nerves situated at the base of the heart that innervates the heart. Structure The cardiac plexus is divided into a superficial part, which lies in the concavity of the aortic arch, and a deep part, between the aortic arch and the trachea. The two parts are, however, closely connected. The sympathetic component of the cardiac plexus comes from cardiac nerves, which originate from the sympathetic trunk. The parasympathetic component of the cardiac plexus originates from the cardiac branches of the vagus nerve. Superficial part The superficial part of the cardiac plexus lies beneath the aortic arch, in front of the right pulmonary artery. It is formed by the superior cervical cardiac branch of the left sympathetic trunk and the inferior cardiac branch of the left vagus nerve. A small ganglion, the ''cardiac ganglion of Wrisberg'', is occasionally found connected with these nerves at their point of junction. This ganglion, when present, is situate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomic Nerves
Autonomic can refer to: *Autonomic nervous system, a division of the peripheral nervous system that supplies smooth muscle and glands, and thus influences the function of internal organs *Autonomic computing Autonomic computing (AC) is distributed computing resources with self-management (computer science), self-managing characteristics, adapting to unpredictable changes while hiding intrinsic complexity to operators and users. Initiated by IBM in 2001 ..., the self-managing characteristics of distributed computing resources See also * Autonomy (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
