Sympathetic ganglia
Encyclopedia
Sympathetic ganglia are the ganglia of the sympathetic nervous system
. They deliver information to the body about stress
and impending danger, and are responsible for the familiar fight-or-flight response
. They contain approximately 20000–30000 nerve cell bodies and are located close to and on either side of the spinal cord in long chains. Sympathetic ganglia are the tissue from which neuroblastoma tumours arise.
, are located just ventral and lateral to the spinal cord
. The chain extends from the upper neck down to the coccyx
, forming the unpaired coccygeal ganglion. Preganglionic nerves from the spinal cord
synapse
end at one of the chain ganglia and the postganglionic fibre extends to an effector, typically a visceral organ in the thoracic cavity
.
There are usually 21 or 23 pairs of these ganglia:
3 in the cervical region,
12 in the thoracic region,
4 in the lumbar region,
4 in the sacral region and a single,unpaired ganglion lying in front of the coccyx called the 'Ganglion impar
'.
, also called the prevertebral ganglia, receive input from the splanchnic nerves
and innervate organs of the abdominal and pelvic
region. These include the celiac ganglia
, superior mesenteric ganglia, and inferior mesenteric ganglia.
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
. They deliver information to the body about stress
Stress (medicine)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
and impending danger, and are responsible for the familiar fight-or-flight response
Fight-or-flight response
The fight-or-flight response was first described by Walter Bradford Cannon....
. They contain approximately 20000–30000 nerve cell bodies and are located close to and on either side of the spinal cord in long chains. Sympathetic ganglia are the tissue from which neuroblastoma tumours arise.
Sympathetic chain ganglia
The bilaterally symmetric sympathetic chain ganglia, also called the paravertebral gangliaParavertebral ganglia
Along the length of the sympathetic trunk are ganglia known as ganglia of sympathetic trunk or paravertebral ganglia. The ganglia are distinguished as cervical, thoracic, lumbar, and sacral and, except in the neck, they closely correspond in number to the vertebrae.-Arrangement:Only the cervical...
, are located just ventral and lateral to the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
. The chain extends from the upper neck down to the coccyx
Coccyx
The coccyx , commonly referred to as the tailbone, is the final segment of the vertebral column. Comprising three to five separate or fused vertebrae below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between...
, forming the unpaired coccygeal ganglion. Preganglionic nerves from the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
synapse
Synapse
In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell...
end at one of the chain ganglia and the postganglionic fibre extends to an effector, typically a visceral organ in the thoracic cavity
Thoracic cavity
The thoracic cavity is the chamber of the human body that is protected by the thoracic wall ....
.
There are usually 21 or 23 pairs of these ganglia:
3 in the cervical region,
12 in the thoracic region,
4 in the lumbar region,
4 in the sacral region and a single,unpaired ganglion lying in front of the coccyx called the 'Ganglion impar
Ganglion impar
The pelvic portion of each sympathetic trunk is situated in front of the sacrum, medial to the anterior sacral foramina. It consists of four or five small sacral ganglia, connected together by interganglionic cords, and continuous above with the abdominal portion...
'.
Collateral ganglia
Neurons of the collateral gangliaCollateral ganglia
Prevertebral ganglia are sympathetic ganglia which lie between the sympathetic chain and the organ of supply.-Function:...
, also called the prevertebral ganglia, receive input from the splanchnic nerves
Splanchnic nerves
The splanchnic nerves are paired nerves that contribute to the innervation of the viscera, carrying fibers of the autonomic nervous system as well as sensory fibers from the organs...
and innervate organs of the abdominal and pelvic
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
region. These include the celiac ganglia
Celiac ganglia
The celiac ganglia or coeliac ganglia are two large irregularly shaped masses of nerve tissue in the upper abdomen. Part of the sympathetic subdivision of the autonomic nervous system , the two celiac ganglia are the largest ganglia in the ANS, and they innervate most of the digestive tract.They...
, superior mesenteric ganglia, and inferior mesenteric ganglia.
External links
- The Autonomic Nervous System from the University of Arizona