|
Gray Ramus Communicans
Each spinal nerve receives a branch called a gray ramus communicans (plural rami communicantes) from the adjacent paravertebral ganglion of the sympathetic trunk. The gray rami communicantes contain postganglionic nerve fibers of the sympathetic nervous system and are composed of largely unmyelinated neurons. This is in contrast to the white rami communicantes, in which heavily myelinated neurons give the rami their white appearance. Function Preganglionic sympathetic fibres from the intermediolateral nucleus in the lateral grey column of the spinal cord are carried in the white ramus communicans to the paravertebral ganglia of the sympathetic trunk. Once the preganglionic nerve has traversed a white ramus communicans, it can do one of three things. * The preganglionic neuron can synapse with a postganglionic sympathetic neuron in the sympathetic paravertebral ganglion at that level. From here, the postganglionic sympathetic neuron can travel back out the grey ramus communicans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Nerve
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 nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system. Structure Each spinal nerve is a mixed nerve, formed from the combination of nerve fibers from its dorsal and ventral roots. The dorsal root is the afferent sensory root and carries sensory information to the brain. The ventral root is the efferent motor root and carries motor information from the brain. The spinal nerve emerges from the spinal column through an opening ( intervertebral foramen) between adjacent verteb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscera
In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system. An organ's tissues can be broadly categorized as parenchyma, the functional tissue, and stroma, the structural tissue with supportive, connective, or ancillary functions. For example, the gland's tissue that makes the hormones is the parenchyma, whereas the stroma includes the nerves that innervate the parenchyma, the blood vessels that oxygenate and nourish it and carry away its metabolic wastes, and the conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacral Ganglia
The sacral ganglia are paravertebral ganglia of the sympathetic trunk.:39 As the sympathetic trunk heads inferiorly down the sacrum, it turns medially. There are generally four or five sacral ganglia. In addition to gray rami communicantes, the ganglia send off sacral splanchnic nerves to join the inferior hypogastric plexus. Near the coccyx, the right and left sympathetic trunks join to form the ganglion impar. The sacral ganglia innervate blood vessels and sweat glands of the lower limbs. Clinical significance Recurrences of genital herpes Genital herpes is an infection by the herpes simplex virus (HSV) of the genitals. Most people either have no or mild symptoms and thus do not know they are infected. When symptoms do occur, they typically include small blisters that break open ... are caused by herpes simplex virus (either HSV-1 or HSV-2) which lies dormant in the sacral ganglia between bouts of active infection. Either primary infection or reactivation may be silent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumbar Ganglia
The lumbar ganglia are paravertebral ganglia located in the inferior portion of the sympathetic trunk. The lumbar portion of the sympathetic trunk typically has 4 lumbar ganglia. The lumbar splanchnic nerves arise from the ganglia here, and contribute sympathetic efferent fibers to the nearby plexuses. The first two lumbar ganglia have both white and gray rami communicates. Function Paravertebral ganglia are divided into cervical, thoracic, lumbar, and sacral ganglia. Each controls different glands and muscle groups since each muscle and gland receives input from postganglionic neurons that originated from different levels of paravertebral ganglia. The lumbar part of the sympathetic trunk contains four interconnected ganglia. Superiorly, it is continuous with thoracic sympathetic ganglion and inferiorly continuous with sacral sympathetic ganglion. Presynaptic neurons traveling from the spinal cord terminate in the paravertebral ganglia (cervical, thoracic, lumbar, sacral) or the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracic Ganglia
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 nerves, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracic Ganglia
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 nerves, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 cranial arteries Nerves emerging from cervical sympathetic ganglia contribute to the 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 superficia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomic Nervous System
The autonomic nervous system (ANS), formerly referred to as the vegetative nervous system, is a division of the peripheral nervous system that supplies internal organs, smooth muscle and glands. The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, its force of contraction, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the fight-or-flight response. The autonomic nervous system is regulated by integrated reflexes through the brainstem to the spinal cord and organs. Autonomic functions include control of respiration, cardiac regulation (the cardiac control center), vasomotor activity (the vasomotor center), and certain reflex actions such as coughing, sneezing, swallowing and vomiting. Those are then subdivided into other areas and are also linked to autonomic subsystems and the peripheral nervous system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Ramus Communicans
The white ramus communicans (plural: rami communicantes) from Latin ramus (branch) and communicans (communicating) is the preganglionic sympathetic outflow nerve tract from the spinal cord. Each of the thoracic, and the first and second lumbar nerves contribute a white ramus communicans to the adjoining sympathetic ganglion, unlike the gray rami which are located at each spinal level. White rami communicantes contain both myelinated and unmyelinated preganglionic sympathetic fibers, ( GVE and GVA). The white ramus appears white because there are more myelinated than unmyelinated fibers unlike the gray rami. Structure The white rami communicantes are the preganglionic sympathetic outflow from the spinal cord. The cell bodies for the preganglionic sympathetic myelinated fibers in the white rami communicantes lie in the ipsilateral (same sided) intermediolateral cell column in the spinal cord which extends from T1-L2. These rami also contain general visceral afferent fibers (se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paravertebral Ganglion
The sympathetic ganglia, or paravertebral ganglia are autonomic ganglia, of the sympathetic nervous system. Ganglia are 20,000 to 30,000 afferent and 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 brain to the body 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 activity. Sympathetic activity could be in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Grey Column
The lateral grey column (lateral column, lateral cornu, lateral horn of spinal cord, intermediolateral column) is one of the three grey columns of the spinal cord (which give the shape of a butterfly); the others being the anterior and posterior grey columns. The lateral grey column is primarily involved with activity in the sympathetic division of the autonomic motor system. It projects to the side as a triangular field in the thoracic and upper lumbar regions (specifically T1- L2) of the postero-lateral part of the anterior grey column. Background information Nervous system The nervous system is the system of neurons, or nerve cells that relay electrical signals through the brain and body. A nerve cell receives signals from other nerve cells through tree-branch-like extensions called dendrites and passes signals through a long extension called an axon (or nerve fiber). Synapses are places where one cell's axon passes information to another cell's dendrite by sending chemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermediolateral Nucleus
The intermediolateral nucleus (IML) is a region of grey matter found in one of the three grey columns of the spinal cord, the lateral grey column. This is Rexed lamina VII. The intermediolateral cell column exists at vertebral levels T1 – L3. It mediates the entire sympathetic innervation of the body, but the nucleus resides in the grey matter of the spinal cord. Rexed Lamina VII contains several well defined nuclei including the nucleus dorsalis (Clarke's column), the intermediolateral nucleus, and the sacral autonomic nucleus. It extends from T1 to L3, and contains the autonomic motor neurons that give rise to the preganglionic fibers of the sympathetic nervous system The sympathetic nervous system (SNS) 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 t ..., (preganglionic sympathetic general visceral efferen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
