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.
Within the axon terminal are many small vesicles containing a neurotransmitter substance called ____. 18. Nerve impulse. When the ______ reaches the ends of the axon, the neurotransmitter is released and diffuses to to the muscle cell membrane to combine with receptors there.19.8. Nerve impulse. When the ______ reaches the ends of the axon, the neurotransmitter is released and diffuses to to the muscle cell membrane to combine with receptors there.