Cholinesterases are enzymes that play a crucial role in the nervous system by breaking down the neurotransmitter acetylcholine. This process is essential for regulating nerve impulses and ensuring that signals between nerve cells are properly terminated, preventing continuous stimulation. There are two main types of cholinesterases: acetylcholinesterase, which primarily acts at nerve synapses, and butyrylcholinesterase, found in the blood and other tissues. Both types are important for maintaining normal muscle function and cognitive processes, and their activity can be affected by certain medications and toxins.