3 Basic Types of Muscle * 1. Skeletal muscle – is voluntary muscle which allows movement of the skeleton and produces body heat. There are two types of skeletal muscle fiber. * Slow –twitch muscle fiber (type I) are oxygen-dependent , produces low force, are slow to fatigue and can contract for longer periods of time. * Fast-twitch muscle fiber (type II) –produces large amounts of force, contract rapidly, are not oxygen dependent but are fast to fatigue. * 2. Cardiac muscle tissue – involuntary muscle tissue which exists only in the heart and facilitates the pumping of the blood through the body. * 3. Smooth muscle tissue – involuntary muscle tissue that lines some of the internal organs, blood vessels and moves food through the stomach and intestines.
Connective tissue * Tendons – Each skeletal muscle is surrounded by a sheet of connective tissue that draws together at the ends of the muscle forming tendons. Tendons attach muscles to bones. * Ligaments – Fibrous, connective tissue that connects bone to bone
Muscle structure * Within each skeletal muscle there are individual muscle cells called muscle fibers which are connected in bundles. Each muscle fiber extends the length of the muscle. Within each muscle fiber are smaller units called myofibrils. Each myofibril consists of many sarcomeres. The sarcomeres contain proteins called actin and myosin. Sarcomeres are responsible for muscle contraction. The actin and myosin filaments slide across each other to cause muscular contraction.
3 Types of Muscle Contractions * Isometric – A muscle contraction with no change in muscle length. This occurs when the muscle contracts against an immoveable object or when movement does not occur. An example is pushing against a wall. You can feel the muscle contract but no movement occurs. * Isokinetic – A muscle