A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.
Acetylcholine. Acetylcholine (ACh) is the transmitter released by the preganglionic nerve terminals of both the sympathetic and the parasympathetic divisions (Fig 6.2). The synapse at those sites utilizes a nicotinic receptor similar in structure to the receptor at the neuromuscular junction.
The drawing depicts an efferent sympathetic nerve (post-ganglionic sympathetic neuron). Such neurons are innervated by pre-ganglionic fibers emerging from the throacolumbar spinal cord. The synapse joining pre-and post-ganglionic sympathetic fibers occurs in the paravertebral ganglia (or sympathetic chain). The pre-ganglionic axons release the neurotransmitter acetylcholine (ACh).