Marker. 1  Noun. A line of credit extended by a casino or cardroom. 2  Noun. A small object placed on top of a player's hand for the purpose of preventing it from being mucked or fouled. 3  Noun. A plastic device used to denote who is in the dealer's position.
Myasthenia gravis is caused by a defect in the transmission of nerve impulses to muscles. It occurs when normal communication between the nerve and muscle is interrupted at the neuromuscular junction -- the place where nerve cells connect with the muscles they control.
From Wikipedia, the free encyclopedia. Myasthenia gravis (from Greek Î¼ÏÏ muscle, á¼ÏÎ¸Î­Î½ÎµÎ¹Î± weakness, and Latin: gravis serious; abbreviated MG) is a neuromuscular disease that leads to fluctuating muscle weakness and fatigue.yasthenia is treated with medications such as acetylcholinesterase inhibitors or immunosuppressants, and, in selected cases, thymectomy (surgical removal of the thymus gland). The disease is diagnosed in 3 to 30 people per million per year.