Myasthenia gravis is thought to be an autoimmune disease characterized by drooping upper eyelids, difficulty swallowing and talking, and generalized muscle weakness. Describe the cause of myasthenia gravis, and explain why it prevents normal muscle function based on the sliding filament theory. Why can acetylcholinesterase inhibitors be effective treatments

It is caused by an error in the transmission of nerve impulses to muscles. It occurs when normal communication between nerve and muscle is interrupted at the neuromuscular junction - the place where nerve cells connect with the muscles they control.

Patients have smaller end plate potentials than normal.With repeated stimulation the endplates potentials become too small to trigger further action potentials and the fiber ceases to contract. Patient with this condition have only 20% acetylcholine receptors.This loss is caused by antibodies directed against receptors.

Acetylcholinestrase inhibitors can be the effective treatment for myasthenia gravis because acetylcholinestrase breaks down the acetylcholine. Some drugs which are used to treat myasthenia gravis acts on acetylcholinistrase to stop the breakdown of acetylcholine. Acetylcholinestrase inhibitors increase the amount of acetylcholine available and so help muscle activation and contraction.