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).
Structure of muscle cells. Each muscle is made of hundreds to thousands of individual muscle cells. Unlike most other cells in the body, these cells are unusually shaped: they are elongated like a cylinder or a long rod. Because of their shape, muscle cells are normally referred to as muscle fibers.