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.
Myasthenia gravis is marked by extreme tiredness and weakness of the muscles in the body. It is caused by lapse of communication between the nerves and the muscles. It is a type of autoimmune disorder wherein the bodyâs own immune system will attack the muscles causing muscular weakness.yasthenia gravis is marked by extreme tiredness and weakness of the muscles in the body. It is caused by lapse of communication between the nerves and the muscles. It is a type of autoimmune disorder wherein the bodyâs own immune system will attack the muscles causing muscular weakness.