What composition does a human bone have, their name in certain departments of the skeleton, and other information you will learn from the materials of this article. In addition, we will tell you about how they are interconnected and what function they perform.
general information
The presented organ of the human body consists of several tissues. The most important of them is bone. So, let's look at the composition of human bones and their physical properties.
Bone tissue consists of two main chemicals: organic (ossein) - about 1/3 and inorganic (calcium salts, phosphoric acid) - about 2/3. If such an organ is subjected to the action of a solution of acids (for example, nitric, hydrochloric, etc.), the lime salts will quickly dissolve, and the ossein will remain. He will keep the shape of the bone. However, it will become more elastic and soft.
If the bone is burned well, then the organic matter will burn, and the inorganic matter , on the contrary, will remain. They will maintain the shape of the skeleton and its hardness. Although at the same time, human bones (the photo is presented in this article) will become very fragile. Scientists have proved that the elasticity of this organ depends on the ossein contained in it, and the hardness and elasticity on mineral salts.
Human Bone Features
The combination of organic and inorganic substances makes the human bone extremely strong and elastic. This is fully convinced by their age-related changes. After all, young children have much more ossein than adults. In this regard, their bones are particularly flexible, and therefore extremely rarely break. As for old people, their ratio of inorganic and organic substances changes in favor of the former. That is why the bone of an elderly person becomes more fragile and less elastic. As a result, the elderly have a lot of fractures, even with minor injuries.
Human bone anatomy
The structural unit of the organ that is visible at a small magnification of the microscope or through a magnifying glass is osteon. This is a peculiar system of bone plates located concentrically around the central channel through which the nerves and blood vessels pass.
It should be noted that osteons do not adjoin each other closely. Between them there are gaps that are filled with bone interstitial plates. In this case, the osteons are not randomly located. They are fully consistent with the functional load. So, in tubular bones, osteons are parallel to the length of the bone, in spongy - perpendicular to the vertical axis. And in the flat (for example, in the skull) - parallel or radial to its surface.
What layers do human bones have?
Osteons together with interstitial plates form the main middle layer of bone tissue. From the inside, it is completely covered with the inner layer of bone plates, and from the outside, by the surrounding. It should be noted that the entire last layer is penetrated by blood vessels that go from the periosteum through special channels. By the way, osteons also comprise larger elements of the skeleton, visible to the naked eye on a radiograph or on a cut.
So, let's look at the physical properties of all bone layers:
- The first layer is strong bone tissue.
- The second is the connective, which covers the bone from the outside.
- The third layer is a loose connective tissue, which serves as a kind of “clothing” for blood vessels that approach the bone.
- The fourth is the cartilage that covers the ends of the bones. It is in this place that these organs increase their growth.
- The fifth layer consists of nerve endings. In the event of a malfunction of this element, the receptors give a kind of signal to the brain.
The human bone, or rather its entire inner space, is filled with bone marrow (red and yellow). Red is directly related to bone formation and blood formation. As you know, it is completely penetrated by the vessels and nerves that nourish not only himself, but also all the inner layers of the organ presented. Yellow bone marrow contributes to the growth of the skeleton and its strengthening.
What are the shapes of bones?
Depending on the location and functions, they can be:
- Long or tubular. Such elements have a middle cylindrical part with a cavity inside and two wide ends, which are covered with a thick layer of cartilage (for example, human leg bones).
- Wide. These are the chest and pelvic, as well as the bones of the skull.
- Short. Such elements differ in irregular, multifaceted and rounded shapes (for example, bones of the wrist, vertebrae, etc.).
How are connected?
The human skeleton (with the name of the bones we will read below) is a set of individual bones that are connected to each other. One or another order of these elements depends on their immediate functions. Distinguish between continuous and continuous connection of human bones. Let's consider them in more detail.
Continuous connections. These include:
- Fibrous. The bones of the human body are interconnected using a pad of dense connective tissue.
- Bone (i.e., the bone has completely grown together).
- Cartilage (intervertebral discs).
Discontinuous connections. These include synovial, that is, between the articulating parts is the joint cavity. The bones are held by a closed capsule and supporting muscle tissue and ligaments.
Thanks to such features, the arms, bones of the lower extremities and the trunk as a whole are able to set a person’s body in motion. However, the motor activity of people depends not only on the compounds presented, but also on the nerve endings and bone marrow contained in the cavity of these organs.
Skeleton Functions
In addition to the mechanical functions that support the shape of the human body, the skeleton provides the ability to move and protect internal organs. In addition, the skeletal system is a place of blood formation. So, new blood cells form in the bone marrow.
In addition, the skeleton is a kind of repository for most of the phosphorus and calcium of the body. That is why it plays a crucial role in the metabolism of minerals.
Human skeleton with bones name.
The skeleton of an adult consists of approximately 200 odd elements. Moreover, each part of it (head, arms, legs, etc.) includes several types of bones. It should be noted that their name and physical features vary significantly.
Head bones
The human skull consists of 29 parts. Moreover, each part of the head includes only certain bones:
1. The brain department, consisting of eight elements:
- frontal bone;
- wedge-shaped;
- parietal (2 pcs.);
- occipital;
- temporal (2 pcs.);
- trellised.
2. The front section consists of fifteen bones:
- palatine bone (2 pcs.);
- opener
- zygomatic bone (2 pcs.);
- upper jaw (2 pcs.);
- nasal bone (2 pcs.);
- lower jaw;
- lacrimal bone (2 pcs.);
- lower nasal concha (2 pcs.);
- hyoid bone.
3. Bones of the middle ear:
- hammer (2 pcs.);
- anvil (2 pcs.);
- stirrup (2 pcs.).
Torso
Human bones, whose names almost always correspond to their location or appearance, are the most easily examined organs. So, various fractures or other pathologies are quickly detected using a diagnostic method such as radiography. It should be noted that one of the largest human bones is the bones of the trunk. These include the entire vertebral column, which consists of 32-34 individual vertebrae. Depending on the functions and location, they share:
- thoracic vertebrae (12 pcs.);
- cervical (7 pcs.), including epistrophy and atlas;
- lumbar (5 pcs.).
In addition, the bones of the body include the sacrum, tailbone, rib cage, ribs (12 × 2) and sternum.
All of these skeleton elements are designed to protect internal organs from possible external influences (bruises, bumps, punctures, etc.). It should also be noted that in case of fractures, the sharp ends of the bones can easily damage the soft tissues of the body, which will entail a severe internal hemorrhage, most often leading to death. In addition, the fusion of such organs requires much more time than for those located in the lower or upper limbs.
Upper limbs
The bones of a person’s hand include the largest number of small elements. Thanks to this skeleton of the upper limbs, people are able to create household items, use them, and so on. Like the spinal column, the human hands are also divided into several departments:
- The belt of the upper limb consists of a scapula (2 pcs.) And a clavicle (2 pcs.).
- The free part of the upper limb has the following parts:
- Shoulder - humerus (2 pieces).
- Forearm - ulnar (2 pieces) and radius (2 pieces).
- A brush that includes:
- the wrist (8 × 2), consisting of scaphoid, lunate, trihedral and pea-shaped bones, as well as trapezium bone, trapezoid bone, capitate and hook-shaped;
- metacarpus consisting of metacarpal bone (5 × 2);
- finger bones (14 × 2), consisting of three phalanges (proximal, middle and distal) in each finger (except for the large, which has 2 phalanges).
All presented human bones, the names of which are quite difficult to remember, allow you to develop hand motility and perform simple movements, which are extremely necessary in ordinary life.
It should be specially noted that the constituent elements of the upper limbs undergo fractures and other injuries most often. However, such bones are fused faster than others.
Lower limbs
The bones of a person’s legs also include a large number of small elements. Depending on the location and functions, they are divided into the following departments:
- Belt of the lower limb. This includes the pelvic bone, which consists of the ilium, the sciatic and pubic.
- The free part of the lower limb, consisting of thighs (femur - 2 pieces; patella - 2 pieces).
- Shin. Consists of tibia (2 pieces) and fibula (2 pieces).
- Foot.
- Tarsus (7 × 2). In its composition, the bones are two pieces each: calcaneal, talus, scaphoid, medial sphenoid, intermediate sphenoid, lateral sphenoid, cuboid.
- Metatarsus, consisting of metatarsal bones (5 × 2).
- Finger bones (14 × 2). We list them: middle phalanx (4 × 2), proximal phalanx (5 × 2) and distal phalanx (5 × 2).
The most common bone disease
Specialists have long been found to be osteoporosis. It is this deviation that most often causes sudden fractures, as well as pain. The unofficial name for the disease presented is "silent thief." This is due to the fact that the disease proceeds imperceptibly and extremely slowly. Calcium is gradually leached from the bones, which entails a decrease in their density. By the way, osteoporosis often occurs in the elderly or adulthood.
Bone aging
As mentioned above, in old age, the human skeletal system undergoes significant changes. On the one hand, bone rarefaction and a decrease in the number of bone plates begin (which leads to the development of osteoporosis), and on the other hand, excessive formations appear in the form of bone growths (or so-called osteophytes). Calcification of the articular ligaments, tendons and cartilage also occurs at their attachment to these organs.
Aging of the osteoarticular apparatus can be determined not only by the symptoms of pathology, but thanks to a diagnostic method such as radiography.
What changes occur due to atrophy of bone substance? These pathological conditions include:
- Deformation of the articular heads (or the so-called disappearance of their round shape, seaming of the edges and the appearance of the corresponding angles).
- Osteoporosis. When examined on an x-ray, the bone of a sick person looks more transparent than that of a healthy person.
It should also be noted that patients often show changes in the bone joints due to excessive deposition of lime in the adjacent cartilage and connective tissue. As a rule, such deviations are accompanied by:
- The narrowing of the articular x-ray gap. This occurs due to calcification of the articular cartilage.
- Strengthening the relief of the diaphysis. This pathological condition is accompanied by calcification of the tendons at the site of bone attachment.
- Bone growths, or osteophytes. This disease is formed due to calcification of the ligaments at the place of their attachment to the bone. It should be especially noted that such changes are especially well detected in the hand and spine. In the remaining parts of the skeleton, 3 main radiological signs of aging are traced. These include osteoporosis, narrowing of the joint spaces and strengthening of the relief of the bone.
In some people, such symptoms of aging can occur early (at about 30-45 years old), while in others - late (at 65-70 years old) or even completely absent. All the described changes are quite logical normal manifestations of the activity of the skeletal system at an older age.
It is interesting
- Few people know, but the hyoid bone is the only bone in the human body that is in no way connected with others. Topographically, it is on the neck. However, traditionally it is attributed to the facial section of the skull. Thus, the sublingual element of the skeleton with the help of muscle tissue is suspended from its bones and connected to the larynx.
- The longest and strongest bone of the skeleton is the femur.
- The smallest bone of the human skeleton is in the middle ear.