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.
What is myasthenia gravis? The term âmyasthenia gravisâ (MG) comes from the Greek word âmyastheniaâ meaning muscle weakness and the Latin word âgravisâ meaning severe. It is an autoimmune condition which causes problems with the transmission of signals from the nerves to the muscles.