ANATOMY

Detailed explanation-1: -Answer and Explanation: A long, filamentous organelle found within muscle cells that has a banded appearance is a myofibril. These form muscle fibers and occur parallel to each other. Myofibrils are comprised of sarcomeres.

Detailed explanation-2: -Each bundle of muscle fiber is called a fasciculus and is surrounded by a layer of connective tissue called the perimysium. Within the fasciculus, each individual muscle cell, called a muscle fiber, is surrounded by connective tissue called the endomysium.

Detailed explanation-3: -Skeletal muscle cells and cardiac muscle cells both contain myofibrils and sarcomeres and form a striated muscle tissue.

Detailed explanation-4: -Within a muscle fiber, proteins are organized into organelles called myofibrils that run the length of the cell and contain sarcomeres connected in series. Because myofibrils are only approximately 1.2 m in diameter, hundreds to thousands (each with thousands of sarcomeres) can be found inside one muscle fiber.

Detailed explanation-5: -Muscle fibers contain numerous tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as alternating dark and light bands.