Structure and functions of the human skeleton. Structure of the skeleton

The skeleton, the photo of which will be presented below, is the totality of the bone elements of the body. The word itself has ancient Greek roots. In translation, the term means "dried". The skeleton is considered a passive part of the musculoskeletal system. It develops from the mesenchyme. Next, consider in more detail the skeleton: the structure, functions, and so on.

Sexual features

Before talking about what functions the skeleton performs, a number of distinctive features of this part of the body should be noted. In particular, some sexual characteristics of the structure are of interest. In total there are 206 bones that make up the skeleton (the photo illustrates all its elements). Almost all are united into a single whole through joints, ligaments and other joints. The structure of the skeleton of men and women is generally the same. There are no cardinal differences between them. However, differences are found only in a few altered forms or in the sizes of the individual elements and systems that they compose. The most obvious differences that the structure of the skeleton of men and women have, for example, include, for example, that the bones of the fingers and extremities of the first are somewhat longer and thicker than those of the latter. In this case tuberosity (areas of fixation of muscle fibers) are expressed, as a rule, stronger in men. In women, the pelvis is wider, and the thorax is narrower. As for sex differences in the skull, they are also insignificant. In connection with this, it is often difficult for specialists to determine who owns it: a woman or a man. Along with this, in the latter, the superciliary arches and hillock protrude more strongly, the orbits are more numerous, the paranasal sinuses are better expressed. In the male skull, the bone elements are somewhat thicker than in the female skull. Anteroposterior (longitudinal) and vertical parameters of this part of the skeleton in men are greater. The skull capacity of women is about 1300 cm ³ . In men, this figure is also higher - 1450 cm ³ . This difference is due to the smaller overall size of the female body.

Head office

In the skeleton, two zones are distinguished. In particular, it has a trunk and head section. The latter, in turn, includes the facial and brain parts. The cerebral part contains 2 temporal, 2 parietal, frontal, occipital and partially latticed bones. In the facial department there is an upper jaw (steam room) and a lower one. In their holes are fixed teeth.

Spine

In this department there are coccygeal (4-5 pcs.), Sacral (5), lumbar (5), thoracic (12) and cervical (7) segments. Vertebral arches form the vertebral canal. The pole itself has four bends. Due to this, it is possible to perform the indirect function of the skeleton associated with the forward movement. Elastic plates are located between the vertebrae. They help improve the flexibility of the spine. The appearance of the bends of the pillar is due to the need to soften the shocks during the movement: running, walking, jumping. Due to this, the spinal cord and internal organs are not subject to shaking. Inside the spine lies the canal. It surrounds the spinal cord.

Rib cage

It includes a sternum, 12 segments of the second spine, and 12 rib pairs. The first 10 of them are joined to the breast bone by cartilages, the latter two do not have articulations with it. Thanks to the thorax it is possible to perform the protective function of the skeleton. In particular, it ensures the preservation of the heart and organs of the bronchopulmonary and partially digestive systems. Behind, the rib plates have a movable articulation with the vertebrae; in the front (except for the lower two pairs) they are connected to the breastbone by flexible cartilages. Due to this, the chest can narrow or expand with breathing.

Upper limbs

In this part there are humeral bones, forearm (ulnar and radial elements), wrist, five metacarpal segments and finger phalanges. In general, the skeleton of the arm is divided into three sections. They include a brush, a forearm and a shoulder. The latter is formed by a long bone. The brush is connected to the forearm and consists of small wrists, a palm forming the palm, and flexible flexible fingers. Attachment of the upper limbs to the body is carried out by means of collarbones and shoulder blades. They form a shoulder girdle.

Lower limbs

In this part of the skeleton, two pelvic bones are isolated. Each of them includes the sciatic, lobny and iliac joints that have grown together. Also, the hip is referred to the lower extremity belt. It is formed by the corresponding (same name) bone. This element is considered the largest of all in the skeleton. The leg is also distinguished in the leg. The structure of this department includes two tibia - large and small. Hangs the lower extremity of the foot. It consists of several bones, the largest of which is heel. The joint with the trunk is carried out by means of pelvic elements. In humans, these bones are massive and wider than in the animal. Joints are used as the connecting elements of the limbs.

Types of articulations

There are only three of them. In the skeleton, the bones can be joined mobile, semi-mobile or immobile. The joint of the latter type is characteristic of cranial elements (except the lower jaw). Semi-rigidly connect the ribs with the sternum and vertebrae. Ligaments and cartilages act as elements of articulation. The movable joint is peculiar to the joints. Each of them has a surface, a liquid present in the cavity, and a bag. As a rule, joints are strengthened by ligaments. Due to them, the amplitude of motion is limited. The joint fluid reduces the friction of bone elements during movement.

What functions does the skeleton perform?

This part of the body has two tasks: biological and mechanical. In connection with the solution of the latter problem, the following functions of the human skeleton are distinguished:

1. Motor. This task is performed indirectly, as the elements of the skeleton serve to attach the fibers of the musculature.
2. Support function of the skeleton. The bone elements and their joints form the skeleton. To him are attached organs and soft tissues.
3. Spring. Due to the presence of articular cartilage and a number of structural features (bends of the spine, arch of the foot), depreciation is carried out. As a result, shocks are eliminated and shocks are mitigated.
4. Protective. In the skeleton there are bone formations, due to which the safety of important organs is ensured. In particular, the skull protects the brain, the sternum-the heart, the lungs and some other organs, the spine-the spinal structure.

Biological functions of the human skeleton:

1. Hematopoietic. The bone marrow is located in the bones. It acts as a source of blood cells.
2. Inventory. Bony elements serve as depots for a large number of inorganic substances. They include, in particular, iron, magnesium, calcium, phosphorus. In this regard, the bones are involved in maintaining a stable mineral composition within the body.

Damage

If the body is positioned incorrectly for an extended period (for example, a prolonged sitting with an inclined head at the table, an uncomfortable posture, etc.), and against a background of a number of hereditary causes (especially in combination with nutritional errors, insufficient physical development) The holding function of the skeleton. In the early stages, this phenomenon can be eliminated quite quickly. Nevertheless, it is better to prevent it. For this purpose, experts recommend choosing a comfortable posture at work, regularly doing sports, gymnastics, swimming and other kinds.

Another fairly common pathological condition is deformation of the foot. Against the background of this phenomenon there is a violation of the motor function of the skeleton. Deformation of the foot can occur under the influence of diseases, become a consequence of injuries or prolonged overload of the foot in the process of body growth. Under the influence of strong physical exertion, a bone fracture can occur. Trauma of this type can be closed or open (with a wound). About 3/4 of all fractures are in the hands and feet. The main sign of injury is severe pain. Fracture can provoke subsequent deformation of the bone, a violation of the functions of the department in which it is located. If suspected of a fracture, the victim should be given an ambulance and hospitalized. Before taking any action, the patient is referred for radiographic examination. In the course of diagnosis, the site of localization of the fracture, the presence and displacement of bone fragments are revealed.