Question

Which organ has only sympathetic supply?

Answer 1

The organ that has only sympathetic supply is the adrenal medulla.

The primary organ that receives exclusive sympathetic innervation the adrenal medulla and acts as a modified ganglion to release epinephrine and norepinephrine directly into your bloodstream.

Other structures that receive only sympathetic input include most blood vessels, arrector pili muscles and the sweat glands.

The Arrector Pili Muscles are responsible for producing goosebumps, and these muscles in the skin receive only sympathetic innervation.

The sweat glands or eccrine sweat glands are stimulated by sympathetic cholinergic fibers.

Most arterioles and veins are also controlled by the sympathetic nerves which increase vascular tone.

And the Adrenal Medulla receives preganglionic sympathetic fibers directly, which triggers a rapid stress response.

The sympathetic supply, or sympathetic innervation, refers to the distribution of nerve fibers from your sympathetic nervous system to your organs, glands and blood vessels throughout your body.

Originating in your thoracolumbar "T1-L3", these often utilize short preganglionic neurons which synapse in ganglia before sending long postganglionic fibers, which release norepinephrine, to target tissues to regulate "fight or flight" responses, which include heart rate acceleration, dilation of pupils and even vasoconstriction.

The originate from the sympathetic supply is the nerve cell bodies, which are located in the lateral gray matter of your spinal cord segments of T1 through L3.

The pathway of the sympathetic supply involves the preganglionic fibers which are relatively short and exit your spinal cord to synapse at sympathetic ganglia, "either in the sympathetic chain or prevertebral ganglia".

And the distribution involves the postganglionic fibers that extend from these ganglia to reach target structures and often travel alongside blood vessels.

The sympathetic supply acts as a widespread regulatory system, which prepares your body for physical demand.

The sympathetic supply increases heart rate and forces contraction, constricts most blood vessels to elevate blood pressure, dilates bronchioles in your lungs to increase intake of oxygen, innervates the dilator pupillae muscle to cause pupil dilation, controls sweat glands, hair erection or piloerection and vasoconstriction in the skin and it also generally inhibits digestive activity and redirects blood flow away from your gastrointestinal tract.

Any disruption of the sympathetic supply can result in specific medical conditions.

For example any damage to your sympathetic fibers that supply your head and neck can lead to Horner's Syndrome, which is characterized by symptoms, like partial ptosis, "drooping eyelid", miosis, "constricted pupil" and lack of sweating also known as anhidrosis on the affected side of the face.