important part of the musculoskeletal system of man - a skeleton consisting of more than two hundred different bones.It enables people to move, supports internal organs.Moreover, human bone is the concentration of mineral substances and the shell, which contains the bone marrow.
Options skeleton
Different types of bones that make up the skeleton of a man, first of all act as a means of support and the support of the body.Some of them serve as the repository of certain internal organs such as the brain, which is located in the skull bones, the heart and lungs located in the chest, and others.
the possibility to make various movements, and we also have to move your own skeleton.Moreover, human bone contain up to 99% of the calcium present in the organism.Of great importance in human life has a red bone marrow.It is located in the skull, spine, sternum, collarbone and some other bones.It originates in the bone marrow blood cells: erythrocytes, platelets and leukocytes.
bone structure
anatomy bone has unusual properties that determine its durability.The skeleton must withstand a load of 60-70 kg - is the average weight of a person.In addition, the bones of the body and limbs act as levers that allow us to perform movements and perform various actions.This is achieved through their amazing staff.
Bones are composed of organic (35%) and inorganic (65%) of material.The former include protein, mainly collagen, which determines the firmness and elasticity of tissues.For hardness correspond inorganics - calcium and phosphorus.The combination of these elements gives a special bone strength is comparable, for example, iron.They may well persist for many years, as evidenced by the results of the various sites.Organic substances may disappear as a result of calcination tissues as well as when exposed to sulfuric acid.Mineral matter is very resistant to external influences.
Human bones are imbued with special tubules, which are the blood vessels.In their structure to distinguish between compact and spongy substance.The ratio is determined by the location of the bones in the human body and of its functions.In areas where resistance to high loads, the core is a dense compact substance.This bone is comprised of a plurality of cylindrical plates placed one inside the other.Cancellous their appearance resembles a honeycomb.Into its cavity is red marrow, and in adults - is also yellow in which concentrated fat cells.Covers special bone connective tissue sheath - periosteum.It is riddled with nerves and blood vessels.
bones
classification There are different classifications that cover all kinds of bones of the human skeleton, depending on their location, structure and functions.
1. On location:
- cranial bones;
- bones of the body;
- limb bones.
2. In the development of the following types of bone:
- primary (arise from connective tissue);
- secondary (formed from cartilage);
- mixed.
3. The following types of human bones in structure:
- tubular;
- spongy;
- flat;
- mixed.
Thus, science knows different kinds of bones.The table makes it possible to more clearly present the classification.
| By location | On development | By building |
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tubular bones
tubular long bones consist of both dense and spongy substance.They can be divided into several parts.Mid-formed compact bone substance and has an elongated tubular shape.This area is called the diaphysis.In his first cavities contain red bone marrow, which is gradually replaced by a yellow, fat-containing cells.
At the ends of the tubular bones is the epiphysis - a portion formed by a spongy substance.Inside it put the red bone marrow.The area between the diaphysis and epiphysis metaphysis called.
In the period of active growth of children and adolescents it is the cartilage, by which the bone and grows.Over time, the bone anatomy changes metaphysis completely transformed into bone tissue.For long bones include the thigh, shoulder, arm bone.Slightly different structure are small tubular bones.They have only one true epiphysis and accordingly one metaphysis.These include the bones of phalanges, metatarsals.They perform the function of the short arm movement.
Spongy bone types.Pictures
name often indicates bone in their structure.For example, cancellous bone formed from the sponge material coated with a thin layer of compact.They have developed cavities, so red marrow is placed in a small cell.Cancellous bone are also long and short.The former include, for example, the sternum and ribs.Short trabecular bone participate in the work of muscles and are a kind of auxiliary machinery.These include the bones of the wrist, vertebrae.
flat bones
These types of human bones, depending on their location, have a different structure and perform certain functions.Cranial bones are primarily protection for the brain.They are formed by two thin plates of dense matter, which is located between the sponge.There are openings for veins.The flat bones of the skull develop from connective tissue.Shoulder and pelvic bones are also a type of flat bones.They are formed almost entirely from cancellous bone, which develops from cartilage.These types of bone function as not only protect, but also support.
irregular bone
Mixed bones represent the connection of flat and spongy or short tubular bones.They develop in different ways and perform the functions that are required in a particular area of the human skeleton.Such types of bones as mixed, occur in the body of the temporal bone of the vertebrae.These include, for example, the collarbone.
Cartilage tissue
Cartilage tissue has an elastic structure.It forms the ears, nose, parts of the ribs.Cartilage tissue located between the vertebrae, as well resists deforming force loads.It has high strength, excellent resistance to abrasion and squeezing.
compound bone
There are different types of connections of bones, which determine their degree of mobility.The bones of the skull, for example, have a thin layer of connective tissue.At the same time they are completely immobile.This connection is called fibrosis.Between the vertebrae are also areas of connective tissue or cartilage.Such a compound called polupodvizhnym as bone, though limited, but may be slightly moved.
The highest mobility have joints that form the synovial joint.The bones are held in joint capsule ligaments.These fabrics are both flexible and durable.In order to reduce friction in the joint is a special oily liquid - synovium.It envelops the ends of bones, cartilage covered and facilitates their movement.
several types of joints.As the name of the bone is determined by their structure and the name of the joint depends on the shape of bones, which they connect.Each type allows you to make certain movements:
- ball joint. With this connection is provided by the movement of the bones in many directions at once.These joints include the shoulder, hip.
- trochlear joints (elbow, knee).Assumes movement solely in one plane.
- cylindrical joint allows the bones to move relative to each other.
- Flat joint. It is slow-moving, low-intensity movement provides between two bones.
- Ellipsoid joint. Thus connected, for example, with a radius bones of the wrist.They can make movements from side to side within the same plane.
- Thanks saddle joint thumb can move in different planes.
Influence of physical activities
degree of physical activity has a significant impact on the shape and structure of the bones.Different people have the same bone may have their own characteristics.At constant physical exertion impressive compact substance thickens and the cavity, on the contrary, it is reduced in size.
adversely affecting the bones of a long stay in bed, a sedentary lifestyle.Fabrics thinner, loses its strength and elasticity, become brittle.
change under the influence of physical activity and the shape of bones.Those places where they are exposed to the muscles may become flatter.In a particularly intense pressure over time can even cause small holes.In areas of high tension which affect bone ligament may be formed thickening various irregularities, bumps.Especially these changes are typical for people who are professionally involved in sports.
The shape of the bone is influenced by a variety of injuries, especially those obtained in adulthood.When healing of fractures can occur all kinds of deformation, which often adversely affect a person's ability to effectively manage his body.
Age-related changes of bone
In different periods of human life is not the same structure of his bones.Babies almost all bones are composed of spongy substance, which is coated with a thin layer of compact.They are continuous, until a certain time, the increase is achieved by increasing the size in the cartilage, which are gradually replaced by bone.This transformation lasts up to 20 years in women and approximately 25 - in men.
The younger the person, the greater the organic matter contained in the tissues of his bones.Therefore, at an early age, they differ in elasticity and flexibility.In adults the amount of mineral compounds in the bone is up to 70%.At a certain point it starts reducing the amount of calcium and phosphorus.Bones become brittle, so the elderly fractures often occur as a result of even a small injury or careless flick.
Such fractures heal for a long time.There is a particular disease, characteristic of elderly people, especially women - osteoporosis.For its prevention when reaching the age of 50 years should consult a doctor to carry out some studies to assess the condition of the bone tissue.With appropriate treatment significantly reduced the risk of fractures and shortening the time of healing.
