Defect in nerve transmission
Myasthenia gravis results from a defect in the transmission of nerve impulses towards the skeletal muscles. The exact cause of this defect in nerve transmission is yet unknown but it disrupts the normal transmission of nerve impulses between the muscles and the nerves at the neuromuscular junction. A neuromuscular junction is the location where the muscles connect with the nerve cells and the acetylcholine receptors suffer from the autoimmune attack on this junction leading to the impairment of nerve transmission. Acetylcholine is a neurotransmitter which helps in the smooth communication of information between different parts of the body. The acetylcholine receptors are present on the nerve ending to get the nerve impulse and signal the muscles to move. However, the disruption in nerve impulse transmission leads to the weaker movements by skeletal muscles.
Older age
The occurrence of myasthenia gravis is more common in older people because the immune system starts tiring out and might mistakenly attacks the acetylcholine receptors thus leading to the development of myasthenia gravis.