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.
Neurotransmitters are chemical impulses released from the axons  vesicles which serves as a messenger to the neighboring neurons. It  stimulates molecular interactions, inclâ¦uding the diffusion of  sodium and potassium ions through the cell membrane which will then  triggers a second set of electrical impulse.