As the bones are connected

Now let us return again to the activities of our musculoskeletal system. If all the bones bodies were fused with each other, we could not move. However, the bones in the majority of cases connected mobile. Mobile compounds of bones is the joint, which, firstly, to facilitate the sliding of the bones to each other, and secondly, tightly fasten them together. Slide achieved by connecting the ends of bones are appropriate form. If a bone - head, on the other hole, etc. Covered articulated the ends of the bones smooth cartilage which continually wetted mucous fluid. Durability of fastening is provided by a joint capsule, i.e. fiber fabric, stretched between the ends of the bones around the entire circumference of the joint. Capsule makes the articular cavity completely sealed. Because it grows slower than the ends of the bones (similar to the ratio between the lungs and chest wall), in joint cavity pressure becomes lower than atmospheric. It is like prikazyvaet bones to each other (like the pumping air from the famous Magdeburg hemispheres so put it that even the horses were unable to overcome this clutch). It is because in the joints we are like a pneumatic cylinder, changes in atmospheric pressure (before bad weather, and so on) sharply respond primarily on the joints in appropriate patients. This means that, first, the capsule holds the bones, creating the tightness of the joint space; second, it binds them additionally by ligaments. Beams especially dense fibrous tissue, held in the most crucial locations capsules, securely connect bones; hence their name - ligament. In total on each side of the body we have about 400 ligaments. The strongest of them Bartenieva link, firming front of the largest joint in the body, the hip. She can bear load of 350 kg Very strong ligaments of the foot. When povertyline foot out sometimes comes off even the inner ankle, and ligaments holding it together with the foot, remain intact.
No matter how great the value of bones and joints, soul movement are, of course, muscles. In structure of muscle cells differentiate smooth muscles of internal organs, are not subordinate to our will, and striated (such they seem under a microscope) of the skeletal muscles, which is in the field of our consciousness. An intermediate position between those and the other is the heart muscle, has striated structure, but not subordinated to our will. Us in this conversation will only be interested in skeletal muscle.
Built muscle fibers. Each fiber is like a colony of fused cells - a lot of nuclei under one cover. In the cytoplasm of such fibers is the mass of thin fibers, which condition the main property of the muscles that generate traffic, - airway. Fiber skeletal muscles are stretched in the form of spindles thickness of 0.01 to 0.1 mm and length up to 5-12 see When fiber is reduced, it is shorter and thicker. All muscle, consisting of thousands of fibers, undergoing the same changes - she's like "inflated".
Muscles thick layer of clothes skeleton, making men on average 40 %, women - 30 % of body weight. A well-developed athletes muscles can take half of body weight and more. Thus, muscle tissue is the most representative in the body. It is on the first place, and very far ahead of other tissues. Skeletal muscles have two functions. First, they provide the motion of a body and its parts. Secondly, they are a powerful additional scrape, elastic connecting all parts of the body. This second function of the muscles is often underestimated, but it is of great importance.