Musculoskeletal system: functions and structure. Development of the musculoskeletal system

All the organs of motion, which ensure the movement of the body in space, are united in a single system. It includes bones, joints, muscles and ligaments. The musculoskeletal system of a person performs certain functions, conditioned by the peculiarities of the formation and structure of the organs of motion.

Significance of the musculoskeletal system

The human skeleton performs several vital functions:

• Supporting;
• Protective;
• Provides movement;
• Takes part in the mineral metabolism and hematopoiesis.

Violation of the musculoskeletal system causes pathological processes in the work of many body systems. Muscles attached to the bones, moving them relative to each other, so that the movement of the body in space is provided. The muscular apparatus has its own functional feature:

• Surrounds the cavity of the human body, protecting them from mechanical damage;
• Perform the supporting function, supporting the body in a certain position.

In the process of development of the musculoskeletal system of a person, CNS development stimulates. The development of muscles and nerve cells is dependent on each other processes. Knowing which functions of the musculoskeletal system are necessary for the normal functioning of the body, we can conclude that the skeleton is a vital body structure.

In the period of embryogenesis, when the body is not affected by any stimuli, the fetal movements cause irritation of the muscle receptors. From these impulses go to the central nervous system, stimulating the development of neurons. At the same time, the developing nervous system stimulates the growth and development of the muscular system.

Anatomy of the skeleton

Skeleton - a set of bones performing the supporting, motor and protective functions. The human musculoskeletal system has about 200 bones (depending on the age), of which unpaired are only 33-34 bones. Distinguish axial (thorax, skull, spine) and additional (free limbs) skeletons.

Bones are formed of bone tissue, belonging to a variety of connective tissue. It consists of cells and dense intercellular substance, which contains a lot of mineral components and collagen, providing elasticity.

The skeleton is a container for the vital organs of man: the brain is located in the skull, the spinal cord in the spinal canal, the thorax provides protection for the esophagus, lungs, heart, the main arterial and venous trunks, and the pelvis protects the organs of the genitourinary system from damage. Violation of the musculoskeletal system can cause damage to internal organs, sometimes incompatible with life.

Structure of bones

A spongy and compact substance is released in the bones. Their ratio varies depending on the location and functions of a certain part of the musculoskeletal system.

The compact substance is localized in the diaphysis of the tubular bones, which provide the supporting and locomotor functions. The spongy substance is located in the flat and short bones. The entire surface of the bone (with the exception of the joint) is covered with a periosteum (periosteum).

Formation of bones

In ontogenesis, the formation of the musculoskeletal system passes through several stages - membranous, cartilaginous and bony. From the second week after conception, a cartilaginous rudiment forms in the mesenchyme of the membranous skeleton. Already by the 8th week the cartilage tissue is gradually replaced by bone.

Substitution of cartilage bone tissue can take place in several ways:

• Perichondrial ossification - formation of bone tissue along the perimeter of the cartilage;
• Periosteal ossification - the production of young osteocytes formed by the periosteum;
• Enchondral ossification - the formation of bone tissue inside the cartilage.

The process of formation of bone tissue is the germination of vessels and connective tissue from the periosteum inside the cartilage (in these places the cartilage is destroyed). From the part of the osteogenic cells the spongy substance of the bone subsequently develops.

During fetal development, fetal ossification occurs (the ossification points are called primary), then the ossification of the epiphyses of tubular bones (secondary ossification points) occurs after birth. Up to the age of 16-24 years, the cartilaginous epiphyseal plate is preserved between the epiphyses and diaphysis.

Due to its presence, the organs of the musculoskeletal system are lengthened. After the cartilaginous tissue is replaced by the bone and the fusion of the diaphyses and epiphyses of the tubular bones occurs, the growth of a person ceases.

Structure of the spinal column

The vertebral column is a successively superimposed vertebrae, which are connected by intervertebral discs, joints and ligaments, by which the locomotor system is based. The functions of the spine are not only in support, but also in protection, preventing mechanical damage to the internal organs and spinal cord passing in the spinal canal.

There are five departments of the spine - coccygeal, sacral, lumbar, thoracic and cervical. Each department has a certain degree of mobility, only the sacral spine is completely immobile.

Movement of the spine or its parts is provided with the help of skeletal muscles. Proper development of the musculoskeletal system in the neonatal period provides the necessary support for internal organs and systems and their protection.

Structure of the chest

The thorax is a bone-cartilaginous formation consisting of the sternum, ribs and 12 thoracic vertebrae. The shape of the chest resembles an irregular truncated cone. The thorax has 4 walls:

• The anterior one is formed by the sternum and cartilage of the ribs;
• Posterior - is formed by the vertebrae of the thoracic spine and the posterior ends of the ribs;
• 2 lateral - formed directly by the ribs.

In addition, two chest openings are identified - the upper and lower apertures. Through the upper opening pass the organs of the respiratory and digestive system (esophagus, trachea, nerves and vessels). The lower aperture is closed by a diaphragm, in which there are openings for passage of large arterial and venous trunks (aorta, inferior vena cava) and esophagus.

Structure of the skull

The skull is one of the basic structures of the axial skeleton, which forms the musculoskeletal system. Functions of the skull - protection of the brain, sense organs and support for the initial parts of the respiratory and digestive systems. It consists of paired and unpaired bones and is divided into the brain and facial sections.

The facial section of the skull consists of:

• Of the maxillary and mandibular bones;
• Two nasal bones;
• The malar bone.

The structure of the cerebral part of the skull includes:

• Frontal bone ;
• Paired temporal bone;
• Paired sphenoid bone;
• Parietal parietal bone ;
• occipital bone.

The brain department performs a protective function for the brain and is its receptacle. The facial section provides support for the initial section of the respiratory and digestive system and sense organs.

Musculoskeletal system: functions and structure of the extremities

In the process of evolution, the skeleton of the extremities acquired extensive mobility due to the joint articulation of the bones (especially in the case of the radial and carpal joints). Allocate the thoracic and pelvic girdle.

The upper belt (thoracic) includes a scapula and two bones of the clavicle, and the lower (pelvic) belt is formed by a pair of pelvic bone. In the free part of the upper limb, the following sections are distinguished:

• Proximal - represented by humerus;
• Middle - represented by the elbow and radius bones;
• Distal - includes the bones of the wrist, metacarpals and bones of the fingers.

The free part of the lower limb consists of the following sections:

• Proximal - represented by the femur;
• Average - includes the tibial and fibular bones;
• Distal - tarsal bones, metatarsal bones and bones of fingers.

The skeleton of the limbs provides the possibility of a wide range of actions and is necessary for normal labor activity, which is provided by the musculoskeletal system. The functions of the skeleton of free extremities can not be overestimated, because with their help a person performs almost all actions.

The structure of the muscular system

Skeletal muscles are attached to the bones and, when contracted, ensure the movement of the body or its individual parts in space. Skeletal muscles are based on striated muscle fibers. In addition to supporting and motor functions, muscles provide the function of breathing, swallowing, chewing, take part in facial expressions, heat generation and articulation of speech.

The main properties of skeletal muscles are:

• Excitability - the activity of muscle fibers is carried out under the influence of nerve impulses;
• Conductivity - from the nerve endings to the central nervous system there is a rapid impulse;
• Contractility - as a result of the movement of the nerve impulse, the contractility of the skeletal muscle is realized.

The muscle consists of the tendon ends (the tendons that attach the muscle to the bone) and the abdomen (consisting of striated muscle fibers). Coordinated work of the musculoskeletal system is performed by the proper functioning of the muscles and the necessary for this nerve regulation of the muscle fibers.