Final answer:
Exposure to nerve gases like Sarin irreversibly inhibits the enzyme acetylcholinesterase, leading to prolonged and potentially fatal muscle contractions due to the accumulation of the neurotransmitter acetylcholine.
Step-by-step explanation:
A patient exposed to nerve gas which inhibits acetylcholinesterase (AChE) would experience prolonged muscle contractions. Nerve agents, including Sarin, lead to the continuous stimulation of muscles because they prevent the breakdown of the neurotransmitter acetylcholine (ACh). Normally, AChE is responsible for hydrolyzing ACh in the synaptic cleft, thus ending the nerve impulse transmission and allowing muscles to relax after contraction. The inhibition of AChE by nerve gases results in an accumulation of ACh, causing relentless stimulation of muscles, which can lead to muscle paralysis and potentially fatal respiratory failure.
Medications used to treat conditions such as Alzheimer's and myasthenia gravis also target AChE to temporarily boost the levels of ACh. However, the irreversible binding of nerve gases to AChE leads to a sustained overstimulation of nerve transmission, far exceeding the controlled effects of these medications. The standard treatment for nerve gas poisoning is atropine, an anticholinergic drug that can manage the symptoms caused by the excessive accumulation of acetylcholine.