Musculoskeletal system: functions and structure. Development of the human musculoskeletal system
All movement organs providing movementbodies 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:
- provides movement;
- takes part in the mineral metabolism and hematopoiesis.
Violation of the musculoskeletal system causespathological 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 a supporting function, supporting the body in a certain position.
In the process of development of the musculoskeletal systema person is stimulating the development of the central nervous system. The development of muscles and nerve cells - dependent 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 bodypractically no stimuli act, the fetal movements cause irritation of the 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 muscular apparatus.
Anatomy of the skeleton
A skeleton is a collection of bones that performsupporting, motor and protective functions. The musculoskeletal system of a man 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 by bone tissue related toa variety of connective tissue. It consists of cells and a dense intercellular substance, which contains many mineral components and collagen, providing elasticity.
The skeleton is a receptacle for vitalhuman organs: the brain is located in the skull, the spinal cord in the vertebral 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.
A compact substance is localized in the diaphysistubular bones that provide support 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 articular) is covered with a periosteum (periosteum).
Formation of bones
In ontogeny, the formation of a systemThe musculoskeletal system undergoes 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 bone formation isgermination of vessels and connective tissue from the periosteum inside the cartilage (in these places the cartilage is destroyed). From the part of osteogenic cells subsequently develops the spongy substance of the bone.
During fetal developmentossification of the tubal bones (the points of ossification are called primary) occurs, then after the birth ossification of the epiphyses of tubular bones occurs (secondary points of ossification). Up to the age of 16-24 years, the cartilaginous epiphyseal plate is preserved between the epiphyses and diaphysis.
Due to its presence, organsmusculoskeletal system. After the cartilaginous tissue is replaced by the bone and the fusion of the diaphysis and epiphyses of the tubular bones occurs, the growth of a person ceases.
Structure of the spinal column
The vertebral column is asuccessively 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 section of the spine is completely immobile.
Movement of the spine or its partsis 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 holes of the thorax- 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 axialThe skeleton, which forms the musculoskeletal system. The functions of the skull are protection of 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 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 department provides support for the initial section of the respiratory and digestive system and sense organs.
Musculoskeletal system: functions and structure of the limbs
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 ulna and radius bone;
- 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 tibial and fibular bones;
- distal - tarsal bones, metatarsal bones and bones of fingers.
The skeleton of the limbs provides an opportunitya wide range of activities and is necessary for the normal work activity that the musculoskeletal system provides. The functions of the skeleton of free extremities can not be overemphasized, since with their help a person performs almost all actions.
Structure of the muscular system
Skeletal muscles are attached to the bones andreduce 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 tendon ends (tendons,which attach the muscle to the bone) and 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.