Muscles are made up of tiny, long fibers. Muscle tissue is used to move the skeleton, but it's also found in the gastrointestinal tract. The heart is also a muscle, which contracts and relax to pump blood to the lungs and throughout the body. Muscle fibers are innervated by the nervous system. Gastrointestinal muscle and the heart are involuntary nerves. Skeletal muscles are voluntary, and they contract when we decide to move the body. This is the main function for muscle fibers.
Function
The main function of muscles is contraction. Within a muscle bundle are tiny myofibrils. "Myo" is a prefix that usually indicates muscle physiology. These cells are the unit of the muscle that contracts and relaxes moving the skeleton muscle. Myofilaments contain actin and myosin. Both of these components are responsible for the force that is applied in the muscle tissue that pulls bones and induces movement.
Types
The three types of muscle in the body are smooth, cardiac and skeletal muscle. Smooth muscle aligns the esophagus and intestines. This muscle pushes food from the mouth and through the gastrointestinal tract. Cardiac muscle is found in the heart. This muscle uses electrostatic energy to contract. The energy comes from the ions within and surrounding the heart cells. Finally, the skeletal muscle is found attached to bone using tendons. These fibers are innervated and activated from voluntary brain impulses.
Identification
Identification of muscle under the microscope requires a trained eye. One physical element of muscle tissue that is unique to these cells are the multinucleated effects seen in the microscope. Most cells in the body have one nucleus unless disease is present. Muscle tissue is multinucleated and it is striated, which means it contains long parallel strands placed side-by-side.
Nutrients
The cell tissue requires high amounts of carbohydrates. Muscle tissue undergoes glycolysis, which is a process where sugar is broken down into two pyruvates and sent to the mitochondria for energy production. For this reason, carbohydrate intake before workouts is recommended. Muscle can also undergo fatty acid oxidation, which is the breakdown of fats to produce energy when sugar is unavailable.
Disease
Disease of the muscular system causes weakness and atrophy in the tissue. Muscular dystrophy is a genetic disease that causes breakdown of the tissue. Autoimmune disorders like myasthenia gravis cause death of the nerves that innervate the cell, which can lead to malfunction of important muscles like the diaphragm and heart. Some muscular disorders are caused by microbes. Tetanus is a muscular disorder caused by a bacterial toxin that promotes muscle contraction and inhibits them from relaxation.
