There are four types of tissue found in animals: connective, muscle, nervous, and epithelial. We are going to go into muscle tissue. The cells of muscle tissues are called fibers. There are three types of muscle tissue and they are skeletal, cardiac, and smooth. All types can go though hypertrophy (enlargement or overgrowth of an organ or part of the body due to the increased size of the constituent cells). Muscle fibers contract due to the interaction of the contractile proteins, actin and myosin. Muscle contraction generates contractile force (tension). The contractile proteins of muscle are located in protein filaments called myofibrils. Muscle tissues function in body movements like locomotion and also in the movement of the body’s internal materials. Muscle tissues are mostly controlled by the nervous system, but cardiac and smooth muscle may be additionally regulated by the endocrine system. Now we are going to go into the types of muscle tissue. The structure of skeletal muscle tissue is formed from striated skeletal muscle fibers (cells). The fibers are characterized by being long, striated, parallel, cylindrical, and multinucleate. The fibers are separated by a connective tissue called endomysium. 80% of the fiber consists of rod-like protein filaments called myofibrils, which extend the length of the fiber and contain the contractile elements. The thick and thin protein filaments are organized to produce the alternating dark and light cross bands perpendicular to the long axes of the fibers called striations. The light cross bands are called I bands (isotrophic bands) and the dark cross bands are called A bands (anisotrophic bands). Centered in each band is a thin line called the Z line. Skeletal muscle tissue is named for its location as its attached to bones (skeletal muscle tissue is organized by connective tissues into the skeletal muscles). Skeletal muscle tissue can be made to contract or relax by conscious control (voluntary). The functional unit