Muscular System
The bones cannot move by themselves. That is the task of the muscles. The muscles that are together to the bones and they allow their movement they call themselves skeletal muscles. The skeletal muscles throw of the bones to move them, they never push them. Most of the muscles work in couples to move the bones.
The muscle is together to the bone for a resistant cord of fabric called tendon. He/she opens up and he/she closes the hand. Do you see those thin cords that you/they go from the fingers to the arm? They are tendons that you/they go from the muscles of the forearm to the fingers. In the organism there are three types of muscles. Besides the skeletal muscles, he/she is the heart muscle and the flat muscles. The heart muscle is the one that forms the heart. The heart is a hollow organ that has four parts, or cameras. The walls of the heart are formed by the heart strong muscle. When this contracts, it expels the blood of the heart. The blood takes oxygen and nutritious to the cells. It also picks up and it transports the waste substances that the cells need to eliminate. When the heart muscle relaxes himself, the heart fills with blood again. The flat muscles constitute the internal organs and the sanguine glasses. These muscles are not together to the bones, but rather they contribute to the operation of other parts of the organism. There are flat muscles in the stomach and in the bowels.
The muscles can be classified according to how their activity is controlled. The heart muscle and the flat muscles are involuntary muscles: their movements cannot be controlled. Most of the skeletal muscles are voluntary muscles: their movements can be controlled. Some muscles are voluntary and involuntary at the same time. An example is that of the big muscle and plan that it is under the lungs. The group of the muscles form the muscular system. You can take care of your muscles exercising physical, eating appropriately, resting enough, and avoiding to take steroids.
