Thoracolumbar Part of Autonomic Division

Description

The thoracolumbar part of the autonomic division is the sympathetic part of the autonomic division, so named because sympathetic neurons originate in the intermediolateral cell column of the lateral horn of the spinal cord at thoracic and upper lumbar spinal cord levels.

Functionally, the sympathetic part of the autonomic division is associated with states of heightened alertness and activity: dilated pupils, increased heart rate, increased blood flow to skeletal muscle, increase in sweat gland function. For this reason, the sympathetic nervous system is often described as part of the fight or flight response.

The different parts of the thoracolumbar part of the autonomic division include:

—preganglionic sympathetic neurons in the lateral horn of spinal cord segments T1 to L2;

—white rami associated with spinal nerves T1 to L2 which transmit sympathetic nerves to the sympathetic chain;

—the sympathetic chain and sympathetic chain ganglia (also known as paravertebral ganglia, preaortic or prevertebral ganglia and are the sites of postganglionic sympathetic neuron cell bodies);

—grey rami communicans, which send sympathetic axons back to spinal nerves at all levels;

—splanchnic nerves (with the exception of the parasympathetic pelvic splanchnic nerves), which are sympathetic nerves traveling from the sympathetic chain towards their target tissues;

—perivascular plexuses, which are collections of sympathetic axons that follow the surface of all arteries, as well as some veins and lymphatic vessels.