The contractile, or functional, unit of a muscle fiber is
Muscle fibers are in turn composed of myofibrils. The myofibrils are composed of actin and myosin filaments, repeated in units called sarcomeres, the basic functional units of the muscle fiber.The sarcomere is responsible for the striated appearance of skeletal muscle, and forms the basic machinery necessary for muscle contraction.n addition to the actin and myosin components that constitute the sarcomere, skeletal muscle fibers also contain two other important regulatory proteins, troponin and tropomyosin, that are necessary for muscle contraction to occur.   The sarcomere is the contractile unit. It is the space between two Z discs that contains one group of myosin fillaments and two groups of actin fillaments, one group on … each end of the myosin fillaments.Z discs join sarcomeres together end-to-end to form myofibrils. In order to achieve t…. 2  Medical Definitions: Motor Unit The medical definition of a motor unit is the combination of muscle nerves and muscle fibers that function together to contract. muscle, muscle fibers, myofibrils, sarcomeres, thick and thin filaments. muscle, myofibrils, muscle fibers, sarcomeres, thick & thin filaments. muscle, sarcomeres, muscle fibers, myofibrils, thick and thin filaments. The ____________________ is/are the functional unit of muscle.uscle, sarcomeres, muscle fibers, myofibrils, thick and thin filaments. The ____________________ is/are the functional unit of muscle. Motor unit consists of a motor neuron and the group of skeletal muscle fibers which it innervates. Three types of motor units are found in skeletal muscle. The largest of these are the type A motor units, which are characterized by high contractile speed and power.-12). There is a relationship between the contraction velocity and the tension developed by a motor unit. As a group, large motor units (those producing the most tension and innervating the greatest number of muscle fibers) contract quickly, while smaller motor units produce less tension and contract more slowly. Making the world better, one answer at a time. The sarcomere is the contractile unit. It is the space between two Z discs that contains one group of myosin fillaments and two groups of actin fillaments, one group on each end of the myosin fillaments. Z discs join sarcomeres together end-to-end to form myofibrils.t is the space between two Z discs that contains one group of myosin fillaments and two groups of actin fillaments, one group on each end of the myosin fillaments. The sarcomere is the contractile unit. It is the space between two Z discs that contains one group of myosin fillaments and two groups of actin fillaments, one group on each end of the myosin fillaments.Z discs join sarcomeres together end-to-end to form myofibrils.t is the space between two Z discs that contains one group of myosin fillaments and two groups of actin fillaments, one group on each end of the myosin fillaments. They are called sacromeres and are the smallest functional 'contractile unit' of a muscle cells that includes myofibilaments, such as actin and myosin. Yes, the above answer i … s correct: But in this particular question that we have Myofibrils is the answer!! In order to achieve t…. 2  Medical Definitions: Motor Unit The medical definition of a motor unit is the combination of muscle nerves and muscle fibers that function together to contract. Each muscle fiber contains myofibrils, which are very long chains of sarcomeres, the contractile units of the cell. A cell from the biceps brachii muscle may contain 100,000 sarcomeres. The myofibrils of smooth muscle cells are not arranged into sarcomeres. The sarcomeres are composed of thin and thick filaments.ach muscle fiber contains myofibrils, which are very long chains of sarcomeres, the contractile units of the cell. A cell from the biceps brachii muscle may contain 100,000 sarcomeres. The myofibrils of smooth muscle cells are not arranged into sarcomeres. The sarcomeres are composed of thin and thick filaments. Since muscle cells are elongated and cylindrical, each muscle cell is usually called a muscle fiber. In skeletal muscle, the muscle fibers are very large, multinucleated, and up to several millimeters in length.tructure and Function of Skeletal Muscle. Let's begin by working our way down through levels of organization in a skeletal muscle until we reach the contractile units that actually generate the force. The sarcomere is the functional or contractile unit of muscle. To recap, a whole muscle if made up of many smaller bundles known as fascicles. Each fascicle is made up of many muscle cells (myofibers). Myofibers contain cylindrical bundles of myofibrils which in turn contain many smaller bundles of myofilaments.otor units allow for selective contraction of muscle fibers so that we may control the strength and extent of muscle contraction. Without motor units a nerve impulse to the muscle would result in the entire muscle contracting to its full extent. That would make every motion that we make an all or none motion.
Sarcomeres