The musculoskeletal system performs the most important functions in the body. This is the movement of the body in space and maintaining its shape, protecting internal organs from mechanical damage, as well as maintaining them in a certain position. The importance of the skeleton for humans is also great. This is the basis without which support and movement are impossible.
Biology: skeleton and features of its structure
The basis of the musculoskeletal system is a set of bones - the skeleton. In humans, it consists of several parts: the skull, trunk, belts and their free limbs. The structure of their components is due to the vertical arrangement of the organism in space. Let's consider them in more detail.
Methods for connecting bones
Bones are connected in different ways depending on the functions performed. A fixed joint is called a seam. In this way, all the bones of the skull are connected. In a newborn child, the parietal bone of the skull consists of cartilage, which over time is replaced by bone. This is necessary so that during birth, the fetus can pass through a fairly narrow female genital tract. Thanks to this structure, the skull is able to change its volume.
Using a semi-mobile connection, the bones of the human spine are combined. Between them are cartilaginous layers capable of compression and stretching. Therefore, spinal mobility is limited. This structure has its advantages: cartilage tissue softens tremors during sudden movements.
Mobile joints of bones are called joints. The main importance of the skeleton for humans is to provide motor activity. It is they who provide this function. Each joint consists of two heads covered with cartilage. Outside, this structure is additionally protected by an articular bag, to which ligaments and muscles are attached. It also releases a special fluid into the cavity, which reduces the friction process.
The elbow joint can only move in one direction, the knee joint in two directions. This is the sign underlying their classification. Depending on the number of directions of movement, one -, two -, triaxial joints are distinguished. An example of the latter is the hip.
Skull
The skeleton of the head is represented by motionlessly connected bones. And only the lower jaw is capable of movement, so we absorb food and talk.
Another meaning of the skeleton for humans is protection. The bones of the skull protect the brain from mechanical damage.
This part of the human skeleton consists of two parts: facial and brain. They, in turn, consist of paired and single bones. For example, the largest components of the facial section are the zygomatic and maxillary. In total, their total number is 15 bones. The brain part of the skull through a hole in the back of the head connects to the canal of the spine. As a result, the anatomical relationship of the brain and spinal cord becomes possible, which is a necessary condition for the normal functioning of the nervous regulation of the human body.
Body skeleton
It is represented by the spine and chest. The skeleton of the body serves as the basis to which the belts and free limbs are attached.
Each vertebra consists of a body and processes, except for the first of them. It is called an Atlas and consists simply of two arcs. An epistrophy is attached to it with its toothlike process - the second in a row. This structure provides turns of the human head. In general, this part of the skeleton consists of 33-34 vertebrae, forming a channel in the cavity of which the spinal cord is located.
The structure of the chest justifies its name. It protects internal organs from shock and deformation. It consists of a flat bone of the sternum, 12 pairs of ribs, which are attached to the thoracic spine.
Skeleton belt
Why wear a belt? To hold clothes. So everyone will answer. In the same way, the belt of limbs, which provides the importance of the skeleton. It is impossible to imagine a person without movement. The bones of the free limbs are attached to the bones of the belts.
Upper - clavicles and shoulder blades. The pelvic and sacral bones belong to the upper limb zones . The former form a half-joint called pubic fusion. The sacrum consists of 5 bones fused into one.
Upper free limbs
Consist of 3 parts: shoulder, forearm and hand. They are connected movably, forming joints. The humerus is attached to the scapula. The forearm is formed immediately by two bones: ulnar and radial. In the hand, in turn, distinguish the wrist, metacarpus and phalanx of the fingers.
Lower free limbs
In this part, the thigh, lower leg and foot are distinguished. Their structure is similar to the upper limbs. A femur is attached to the pelvic bones - the longest in the human body. The tibia consists of the tibia and tibia. And the foot - from the tarsus, metatarsus and phalanges of the fingers.
Skeleton and upright
What is the meaning of the skeleton for a person and his life, we found out. But there is another important aspect. All the features of the human skeleton are associated with its horizontal position in space.
The table "The human skeleton and the features of its structure in connection with upright posture" clearly demonstrates this.
| Part of the skeleton | Structural features |
| Skull | The brain is more developed than the front. |
| Rib cage | Flattened in the dorso-abdominal direction, extended to the sides. |
| Spine | It forms several bends that soften tremors during movement and act as shock absorbers when walking. |
| Upper limbs | The thumb of the hand is opposed to the rest, which is associated with the ability of a person to work. |
| Lower limbs | The pelvic bones are expanded, forming a kind of bowl that helps to keep the body in a horizontal position. The foot is vaulted, the structure of which allows you to ease tremors when walking, jumping and running. |
A decrease in the facial part of the skull is associated with an increase in the volume of the human brain. Its development was influenced by the development of speech and abstract thinking.
Anthropology - the science of the origin of man, claims that he is the result of evolutionary processes. One of their driving factors is natural selection. Its essence lies in the fact that, as a result, individuals survived, capable of manufacturing the simplest tools and working with them. This is possible only with the special structure of the brush. The chest in animals is extended downward. It is quite difficult for such organisms to move on two legs.
Thus, the human skeleton has all the features necessary for spinning, providing the ability to change the position of individual parts and the entire body in space.