The basis of the human skeleton. The bones of the skeleton

Man, thanks to his musculoskeletal system, can easily move. Such a mechanism may be passive and active. The latter part – the muscle mass of a person. In the passive mechanism includes bones, United in a certain way.

What is the human skeleton?

The Skeleton in translation from Greek means dried or dried. It is a whole system or complex of bones that perform a large number of actions, including musculoskeletal, protective, formative, etc. In General, the skeleton - based body, he has a lot of one-seventh to one-fifth of the total body weight. It's more than 200 bones, which can be paired and unpaired. The latter include the sternum, vertebrae, coccyx, sacrum, sternum, some of the bones of the cranium.

Skeleton

The human Skeleton contains internal organs, which it protects from external negative factors. The skull protects the brain vertebral canal - spinal cord, the sternum protects heart, lungs, major vessels, esophagus etc. Hip-based skeleton retains the genitourinary organs. It performs other functions, for example, involved in the metabolism, that is supported at a certain level, the mineral composition of blood. In addition, some of the substances included in the composition of the bones also can engage in the metabolic processes of the human body.

Bones are attached To ligaments, muscles, tendons – “soft skeleton”, because they also contribute to the protection and retention of organs inside. Any part of the body can change its position in relation to each other, thereby moving us in space. These actions perform the bones of the skeleton – after all, they are kind of levers, powered by muscles.

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Bone Form

They differ by their form and perform various functions. There are bones of the skeleton, which can be long (shoulder bone) short (phalanges).

Long bones are composed of:

1. Body – an elongated middle part.
2. Thickened end – of the epiphyses.

The Middle part of the bone core inside. Wide and flat pieces form the wall of a place where internal organs such as the bones of the skull, pelvis, sternum. The length and width of them strongly dominated by the thickness. To consider different shape of the bones will help the image: the skeleton is completely or only specific types of bones. Mixed types have a fairly complex form and sometimes consist of several parts with different structure and shape, e.g. vertebrae.

Bone Structure

The Basis of our body must be very strong, because the skeleton – this support, which has to withstand quite a lot of weight, on average 60-75 kg. All the bones of the human skeleton have a complex chemical composition. They include organic and inorganic elements. This is mainly salts of calcium and phosphorus (about 70%), making the bone more solid. Cells 30% consist of organic matter, giving the basis of the body elasticity and firmness. The combination of these substances makes bone more durable, and this is a very important point, as the basis of the skeleton should possess such properties.

The children and young people's bones are more elastic and flexible, thanks to a high content of organic substances. Than older people, so they become more fragile and therefore more brittle. The main type of connective tissue-bone tissue is composed of cells and intercellular substance. Plate inserted into one another, with such a structure ensures a high strength and at the same time lightness.

Bone also consists of dense and spongy substance. The ratio depends on its location and functions. Dense substance highly developed in those bones and their parts that comprise the locomotor apparatus the basis of the human skeleton (the example of bone).

The Spongy substance composed of many plates, which are arranged in the direction of greatest stress. In short and flat bones and at the ends (epiphyses) of long between records is a red brain, from which the formation of blood cells. Cavity of the long bones of an adult filled with fat cells. They are also called yellow marrow. The outer portion of the support levers is covered by a thin connective sheath – the periosteum.

Bone Growth

Bones of the human skeleton slow down and soon entirely cease to grow. In women, it happens to 20 years, men - 25. Bones grow in width due to cell division of the inner layer of the periosteum. They also grow in length. Their size increases due to the cartilage that lies between the body of the bone and its end.

How do bones fit together?

All the bones of the human skeleton interact with each other. Distinguish between continuous (stationary and polupodvizhnym) and discontinuous connection. About the first case is when the bones of the skull or pelvis are attached to each other. There is a view of a fixed connection. Between the bones is a thin layer of connective tissue or cartilage. Some compounds, for example, the skull is called pinked seams. A more accurate understanding of how the bones are attached to each other, help pictures. Skeleton, skeleton bones, skull – all ways of connecting are very clearly presented in these figures in the article.

Polupodvizhnym connection attached between the bones of the spine, tibia and fibula. Small motor activity data of the compounds attach to the cartilage semi-rings. Form the basis of a skeleton Spine, skull, torso, upper and lower limbs, but they go a little later.

Movable connection of bones – joints. Heard about them each. For example, the joint between the bones of the pelvis and the thigh resembles the shape of a hinge. Hence their name. This form of joint allows bones to move backward and forward, to make move from side to side, and rotate around its axis.

The Joints are also ellipsoid, saddle, hinge and flat shape. In some types it is possible to move only on one axis (uniaxial joints), in others - around 2 axes (biaxial), etc. the Joint is called simple, if it is formed by two bones, and a "complex" if three or more.

Connective tissue skeleton

The Skeleton consists of bones and cartilage. They in turn are made up of cells and dense intercellular substance. Have bone and cartilage General structure, origin and function. The first develop from the latter, for example bones of the skull base, vertebrae, lower limb, etc. Some of the bones develop without the cartilage – the clavicle, lower jaw, etc.

Fetus in humans and some vertebrates the cartilaginous skeleton is about 50% of the total body mass. But he gradually is replaced by bone in the adult, such a mass is only about 2% of the total body weight. The cartilage of the nose and ear, bronchi, and ribs, intervertebral discs, articular cartilage, tracheal cartilage semi-rings form the basis of the skeleton, because without them it is impossible to fully functioning of the human body as a whole.

Cartilage perform the following functions:

1. Cover the connecting surface of the bone, making them more resistant to wear and tear.
2. Carry out the cushioning and motion compression, and expansion joints and intervertebral disks.
3. Form the Airways and the external ear.
4. These are attached tendons, muscles and ligaments.

Axial skeleton

All the bones divided into the axial skeleton and incremental. The first consists of:

1. Skull-bone parts of a human head, which includes the brain, the organs of hearing, sight, smell. The skull consists of the face and brain Department.
2. Chest-bone basics of the breast, consisting of twelve thoracic vertebrae, the sternum and 12 pairs of ribs.
3. The Spine or vertebrae – the basis of the skeleton. Also referred to as the main pillar of the human body. Inside the spine is the spinal cord.

Additional skeleton

Additional skeleton consists of two parts:

1. Belt of the upper extremities, which ensures the joining of the upper parts to the support, which is the basis of the skeleton. This belt consists of shoulder blades and collarbone. The upper limb consists of 3 sections: shoulder, forearm and hand.
2. Belt of the lower extremities, which provides a connection to the axial skeleton and serves as the container and support urinary, digestive and reproductive systems. It is formed from the pelvic, sciatic, pubic bone. The lower limb consists of hip, thigh, podkolonnik, legs, feet, etc.

This article is very brief, but very descriptive describes the structure of the human skeleton. This is a very difficult question to explore it fully, you need to study medical literature.