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.
Human Anatomy & Physiology: Muscle Physiology; Ziser Lecture Notes, 2006 2 Muscle Cell Contraction: 1. nerve impulse arrives at neuromuscular junction 2. ACh is released and diffuses across synapse 3. binds to receptor on sarcolemma and initiates an impulse 4. impulse travels across sarcolemma and into T tubules 5. impulse triggers release of Ca++ from SR 6.