Biochemistry The action of acetylcholine at the neuromuscular junction is terminated primarily by: A Diffusion into the surrounding extracellular fluid B Uptake into the nerve ending C Uptake into the muscle D Enzymatic breakdown by acetylcholinesterase 💡 Explanation The action of acetylcholine at the neuromuscular junction is terminated primarily by: ✓ Correct Answer: D. Enzymatic breakdown by acetylcholinesterase