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.
Confidence votes 4.9K. Most neurons have a chemical synapse, which is to say that a substance called a neurotransmitter is released from the first neuron (called pre-synaptic) to the next neuron called (post-synaptic).he neurotransmitter binds to specific receptors on the post-synaptic membrane and that causes the action potential to propagate on (or for the neurotransmitter to cause an action like a muscle contraction).