extensor
The nervous system is communicating with the body every moment that you are alive. It sounds like you are refering to some kind of muscle spasm or tension.
Extensor
It's a muscle - in fact, it's the strongest muscle in the human body
"muscle"
Muscle Cells
Approximately half of the human body weight is composed of skeletal muscle that is voluntarily controlled. It is also referred to as striated muscle.
Since "Not every man is moral" then Every man is moral is Particular.
Everywhere! Every structure and tissue in the body is made of one kind of cell or another: blood cells, bone cells, muscle cells, skins cells, nerve cells, & many more kinds.
There are three types of muscles in the body, smooth, skeletal and cardiac. The only place you'll find cardiac muscle is in the heart.
Muscle cells contract, causing movement and our heartbeat.
Smooth muscle tissue is the type of muscle tissue found in the walls of many organs and blood vessels in the body.
Cardiac means "of or relating to the heart". Cardiac muscle has that name because it is the specific kind of muscle found only in the heart. It is a very special kind of muscle, very efficient and different from other muscles.