An individual muscle fiber may also be called a myofiber or a muscle cell. Each muscle fiber is a single, narrow cell that spans the entire length of a muscle. There are three different kinds of myofibers found in the body: skeletal, cardiac and smooth.Continue Reading
Myofibers are composed mostly of cylindrical bundles of proteins. There are two different types of protein filaments found in each muscle fiber: actin and myosin. When these filaments slide past one another, the muscle contracts. Each myofiber is surrounded by a membrane called a sarcolemma. Groups of muscle fibers are bundled together and encapsulated in connective tissue to form an entire muscle.
The cells that compose skeletal muscles, which are the muscles that connect to the bones and allow individuals to run, bend their arms and turn their heads, are voluntary, which means that each person decides when to contract them. Most of the muscles in the body are skeletal muscles, and they comprise an average of 40 percent of a person's body mass. Cardiac muscle cells, which are found in the heart, and smooth muscle cells that line the intestines and blood vessels, are involuntary, which means that the brain automatically controls their contractions.Learn more about Muscles
Fast twitch and slow twitch muscles are types of muscle fiber used to perform different kinds of physical activity. For example, slow twitch muscles in the lower leg aid in standing, while fast twitch muscles in the eyelid enable blinking.Full Answer >
The type of muscle used to straighten a joint is called an extensor muscle. The feet, legs, spine, arms and hands all have extensor muscles to aid in movement.Full Answer >
Muscles that cause two bones on two different sides of the joint to close, resembling a bending action, are called flexor muscles. However, each muscle has the ability only to pull, not to push, so muscles need to work in pairs.Full Answer >
A person knows that he has a pulled muscle by the symptoms produced by this injury, which are pain in the affected area, inflammation, muscle weakness, bruising and muscle tightness. Although these are signs of a muscle pull or strain, there are grades associated with this injury.Full Answer >