Using a customer supplied envelope, an individual can mail a Priority Mail Express letter envelope weighing one ounce up to sixteen ounces for $31.20 plus the extra fee of $12.50 to add Sunday/Holiday Delivery.
muscle cell-an elongated contractile cell that forms the muscles of the body. muscle fiber, muscle fibre. fibre, fiber-any of several elongated, threadlike cells (especially a muscle fiber or a nerve fiber).
This shortening is called a muscle contraction. There are three types of muscle cells in the human body: 1  Skeletal muscle: Drives voluntary movement.  Cardiac muscle: Cells of the heart that pump blood.