Ocular Sympathetic Pathway Flashcards
Sympathetic pathway begins in which portion of the spinal cord
Thoracolumbar T1-L2.
Sympathetic pathway begins where in the spinal cord for OCULAR structures
Originates in T1-T3
Preganglionic fibers travel along with ___ nerves and enter the sympathetic chain.
They travel along with thoracic nerves. Since they are exiting the thoracolumbar area.
Once preganglionic axons synapse in the superior cervical ganglion, where do postganglionic fibers travel?
Post ganglionic fibers exit the ganglion, ascend and wrap around the nearby internal carotid artery to form the carotid plexus. They travel with the internal carotid artery into the skull through the carotid canal. The post ganglionic axons branch off once they reach the cavernous sinus and travel to the eye.
What is the carotid plexus
When post ganglionic neurons traveling from the sympathetic chain wrap around the internal carotid artery and hitch a ride into the skull.
What is the role of Muller’s muscle
It is a smooth muscle in the upper and lower eyelid. It is an accessory retractor muscle. Keeps the eyelids open voluntarily.
Where do sympathetic fibers travel to innervate mullers muscle
The fibers travel with CN III to reach mullers muscle. CN III and mullers both have a superior and inferior division.
Stimulation of the sympathetic nervous system causes ____ of mullers muscle
Contraction
Where do sympathetic fibers travel to innervate the iris dilator
The fibers travel with CN V1 to the nasocilliary nerve to the long ciliary nerve to the iris dilator.
Stimulation of the sympathetic nervous system causes ___ of the iris dilator
Contraction, which result sin mydriasis
Stimulation of the sympathetic nervous system affect the sweat glands how
Causes secretion of sweat
Horners syndrome
Sympathetic denervation. Thats why it results in ptosis, meiosis and anhydrosis on the affected side.
Stimulation of the sympathetic nerve causes ___ of conjunctival blood vessels, choroidal blood vessel, and lacrimal gland blood vessels.
Vasoconstriction
