All the organs of motion that ensure the movement of the body in space are combined into a single system. It includes bones, joints, muscles and ligaments. The musculoskeletal system of a person performs certain functions, due to the peculiarities of the formation and structure of the organs of movement.
The value of the musculoskeletal system
The human skeleton performs several vital functions:
- supporting;
- protective;
- provides movement;
- takes part in mineral metabolism and blood formation.
A violation of the musculoskeletal system causes pathological processes in the work of many body systems. Muscles attached to bones carry out their movement relative to each other, which ensures the movement of the body in space. The muscular apparatus has its own functional feature:
- surrounds the cavity of the human body, protecting them from mechanical damage;
- perform a supporting function, supporting the body in a certain position.
In the process of development of the musculoskeletal system of a person, the development of the central nervous system is stimulated. The development of muscles and nerve cells are interdependent processes. Knowing what 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.
During the period of embryogenesis, when practically no stimuli affect the body, fetal movements cause irritation of muscle receptors. From them, 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 muscle apparatus.
Skeleton anatomy
Skeleton - a set of bones that perform supporting, motor and protective functions. The musculoskeletal system of a person has about 200 bones (depending on age), of which 33-34 are unpaired. There are axial (chest, skull, spine) and additional (free limbs) skeletons.
Bones are formed by bone tissue belonging to a type of connective tissue. It consists of cells and a dense intercellular substance, which contains many mineral components and collagen, which provides elasticity.
The skeleton is a receptacle for vital human organs: the brain is located in the skull, the spinal cord is located in the spinal canal, the thorax protects the esophagus, lungs, heart, 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.
Bone structure
A spongy and compact substance is secreted 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 support and locomotor functions. The spongy substance is located in flat and short bones. The entire surface of the bone (with the exception of the articular) is covered with a periosteum (periosteum).
Bone formation
In ontogenesis, the formation of the musculoskeletal system goes through several stages - membranous, cartilaginous and bone. From the second week after conception, the formation of cartilaginous primordia occurs in the mesenchyme of the membranous skeleton. By the 8th week, the cartilage tissue is gradually replaced by bone.
Bone cartilage can be replaced in several ways:
- perichondrial ossification - the formation of bone tissue along the perimeter of the cartilage;
- periosteal ossification - the production of young osteocytes by the formed periosteum;
- enchondral ossification - the formation of bone tissue inside the cartilage.
The process of formation of bone tissue consists in the germination of blood vessels and connective tissue from the periosteum into the cartilage (in these places cartilage is destroyed). From the part of osteogenic cells, the spongy substance of the bone subsequently develops.
During intrauterine development of the fetus, the diaphysis of the tubular bones is ossified (the ossification points are called primary), then after birth, the epiphyses of the tubular bones are ossified (secondary ossification points). Until the age of 16-24 years, between the epiphyses and diaphysis, the cartilaginous epiphyseal plate is preserved.
Due to its presence, the organs of the musculoskeletal system are lengthened. After the cartilage is replaced by bone and fusion of the diaphysis and pineal gland epiphyses occurs, human growth ceases.
Spinal column structure
The vertebral column is a series of overlapping vertebrae, which are connected by intervertebral discs, joints and ligaments, which are based on the musculoskeletal system. The functions of the spine are not only in support, but also in protection, preventing mechanical damage to internal organs and the spinal cord passing in the spinal canal.
There are five sections of the spine - coccygeal, sacral, lumbar, thoracic and cervical. Each department has a certain degree of mobility, only the sacral spine is completely motionless.
The movement of the spine or its departments is provided with the help of skeletal muscles. The proper development of the musculoskeletal system in the neonatal period provides the necessary support for the internal organs and systems and their protection.
Chest structure
Chest - a bone-cartilage formation consisting of a sternum, ribs and 12 thoracic vertebrae. The shape of the chest resembles an irregular truncated cone. The chest has 4 walls:
- front - formed by the sternum and cartilage of the ribs;
- back - 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 distinguished - the upper and lower apertures. The organs of the respiratory and digestive systems (esophagus, trachea, nerves and blood vessels) pass through the upper opening. The lower aperture is closed by a diaphragm, in which there are holes for the passage of large arterial and venous trunks (aorta, inferior vena cava) and the esophagus.
Skull structure
The skull is one of the main structures of the axial skeleton, which forms the musculoskeletal system. The functions of the skull are to protect the brain, sensory organs and support for the initial parts of the respiratory and digestive systems. It consists of paired and unpaired bones and is divided into cerebral and facial sections.
The facial section of the skull consists of:
- from the maxillary and mandibular bones;
- two nasal bones;
- zygomatic bone.
The composition of the brain part of the skull includes:
- frontal bone ;
- paired temporal bone;
- paired sphenoid bone;
- paired 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 systems and sensory organs.
Musculoskeletal system: functions and structure of limbs
In the process of evolution, the skeleton of the limbs gained extensive mobility due to the articular articulation of the bones (especially for the radial and carpal joints). Allocate the chest and pelvic girdles.
The upper belt (pectoral) includes the scapula and two bones of the clavicle, and the lower (pelvic) is formed by a paired pelvic bone. In the free part of the upper limb, the following departments are distinguished:
- proximal - represented by the humerus;
- the middle one is represented by the ulnar and radial bones;
- distal - includes the bones of the wrist, metacarpal bones and finger bones.
The free part of the lower limb consists of the following departments:
- proximal - represented by the femur;
- middle - includes the tibia and fibula;
- distal - tarsal bones, metatarsal bones and finger bones.
The skeleton of the limbs provides the possibility of a wide range of actions and is necessary for normal labor activity, which provides the musculoskeletal system. It is difficult to overestimate the functions of the skeleton of free limbs, since with their help a person performs almost all the actions.
The structure of the muscle system
Skeletal muscles are attached to the bones and during contraction provide movement of the body or its individual parts in space. Skeletal muscle is based on striated muscle fibers. In addition to supporting and motor functions, the muscles provide the function of breathing, swallowing, chewing, take part in facial expressions, heat production 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;
- conduction - from the nerve endings to the central nervous system there is a rapid impulse;
- contractility - as a result of the movement of a nerve impulse, contractility of the skeletal muscle is carried out.
A muscle consists of tendon ends (tendons that attach the muscle to the bone) and an abdomen (consisting of striated muscle fibers). The coordinated work of the musculoskeletal system is carried out by the correct functioning of the muscles and the necessary nervous regulation of muscle fibers.