Spongy bone

Most bones of the human skeleton are composed of two structurally distinct types of tissue compact (dense) and trabecular (cancellous, spongy) bone. Both types contain the same elements cells ( osteocytes) embedded in a mineralised matrix and connected by small canals ( canaliculi ). In compact bone, which makes up 85% of the skeleton, these components form elongated cylinders of concentric lamellae surrounding a central blood vessel (called osteon or Haversian system). Cancellous bone, in contrast, forms thin,... 

Turbinate Any of the scrolled spongy bones of the nasal passage. 

Bone. The structure of bone was described in Section 1.5.2. Recall that bone is a composite material, composed primarily of a calcium phosphate form called hydroxyapatite (HA). The major support bones consist of an outer load-bearing shell of cortical (or compact) bone with a medullary cavity containing cancellous (or spongy) bone toward the ends. 

The following is the modus operands, —It is proper to obserro that all bones do not answer for this manufacture. Only spongy bones can be used the ribs, the back-bone, the lower jaw-bone of animals, and the horns, are those which yield tlie greatest amount of gelatin. The bones are broken as small as possible by means of an axe. Some hydrochloric acid of... 

Spongy bone Circumferential, concentric lamellar Stores blood cell... 

Mechanical properties of cancellous (spongy) bone are dependent on the bone density and porosity, and therefore the strength and stiffness of spongy bone is much lower than that of cortical or osteonic bone. The axial compressive strength is related to the square of the bone density. 

There are two types of bony tissue cancellous or spongy bone and cortical or compact bone. Cortical bone is denser and more highly ordered than the randomly woven cancellous bone tissue. Cancellous bone is open-celled and porous, with from 30% to over 90% porosity. 

Postnikov SS, Nazhimov VP, Semykin Sin, Kapranov NI. [Comparative morphological analysis of the articnlar cartilage, epiphyseal plate, spongy bone, and synovial membrane of the knee joint in children treated and not treated with ciprofloxacin.]Antibiot Khimioter 2000 45(11) 9-13. 

The main functions of bone are (1) mechanical, for locomotion (2) protective, for organs and (3) metabolic, as a reserve for minerals, especially calcium and phosphate. Bones are composed of cortical and trabecular bone. Cortical (compact) bone is 80% to 90% mineralized by volume and constitutes 80% of the skeleton. Its function is primarily mechanical and protective. Trabecular bone constitutes the remaining 20% of the skeleton. Trabecular (cancellous or spongy) bone, which is 15% to 25% mineralized, is more metabolicaUy active. 

Trabecular bone Spongy bone tissue found in the interior of bone. 

In lead workers, this fraction may be even higher. There are at least two pools of lead in the skeleton one is found in trabecular, spongy bone (Schiitz et al. 1987a) and the other in cortical, compact bone (Christoffersson et al. 1984, Somervaille etal. 1989, Gerhardsson etal. 1993). The skeleton contains 20% trabecular bone... 

The percent of plutonium-239, administered by intravenous injection as the citrate or as the polymer, that distributed to the skeleton of dogs and mice was 2.8 to 3.1 % or 0.1 to 0.2%, respectively, after 6 days (Baxter et al. 1973). In rats 30 days after exposure to plutonium-239 as the citrate or as the polymer, 56.9 or 29.4%, respectively, distributed to the bone (Carritt et al. 1947). In dogs plutonium distribution in the skeleton was greatest to the trabecular or "spongy" bone and more was found in the red bone marrow, which is perfused with blood, compared with yellow or fatty bone marrow (Smith et al. 1984 Wronski et al. 1980). The rate of deposition in bone may be related to the rate of blood flow to bone, and in mice there appears to be a threshold rate for blood flow below which plutonium will not deposit to bone (Humphreys et al. 1982). 

It comprises a matrix of coiiagen fibres (30%) impregnated with bone salts (70%), mostiy c cium phosphate, in which are embedded bone cells (seeosxEocvTE osteoblast osteoclast). Bone generally replaces embryonic cartilage and is of two sorts - compact bone and spongy bone. 

The outer compact bone is formed as concentric layers (lamellae) that surround small holes ( Haversian canals) see illustration. The inner spongy bone is chemically similar but forms a network of bony bars. The spaces between the bars may contain bone marrow or (in birds) air for lightness. See also CARTILAGE BONE MEMBRANE BONE periosteum. 

SPM SeeSCANNING PROBE MICROSCOPY, sponges SeePoRiPERA. spongy bone See bone. spongy mesophyll SeeMESoPHYii.. 

Trabecular or cancellous bone is spongy in nature and occupies about 20% of the total bone. Cancellous bone is lighter, less dense, has higher porosity (pores diameter varies from a few micrometers to millimeters), and a higher concentration of blood vessels than compact bone (also called cortical or dense bone) (Fig. 2). The porous architecture of cancellous bone is easily visible under the microscope or even with the naked eye because it contain very large pores. Cortical bone, which has less porosity and thus a lower concentration of blood vessels, occupies about 80% of the total bone. Due to its lower porosity, its porous architecture is not visible to the naked eye. The diameters of pores are 10-20 pm and mostly separated by 200-300 pm intervals. Spongy bone acts mainly in compression, whereas compact bone acts mechanically in torsion, tension, and compression. 

At the microstructural level, the Haversian system or osteon is the repeated structural unit of compact bone, which acts as a weight-bearing pillar. In contrast, spongy bones are made of an interconnecting framework of trabeculae. There are three types of cellular structures in the trabeculae, (1) plate/platelike, (2) plate/ barlike, and (3) bar/barlike. The bone tissue primarily consists of collagen nanofibers and bone minerals crystals (particularly HAp) at the nanostructural level. 

Figure 16.3. SEM of the trabeculae of spongy bone (left) showing bone micro and nanostructure (note the pores range from 10s of nanometer to submicron scale) and our engineered nanotubulartitania surfaces with cell extending its processes.

These requirements derive from the bone complex structure and properties. Bone is a complex and dynamic living tissue, which from morphological point of view can be divided into two types cortical or compact bone and trabecular or cancellous or spongy bone. The mass of the skeleton is composed of 80% compact bones and 20% spongy bones. Cortical and trabecular bones contain the same cells and extracellular matrix (ECM) components, except that they are organized in a different way. The trabecular bone consists of a porous matrix with intercormected columns filled with bone marrow and is being responsible for metabolic functions of the bone, while the cortical bone contains fewer spaces, forms the external layer of all bones and provides them protection and load-bearing capabilities (Baron, 2003, as cited in Wilson, 2011). 

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