Spongy Bone Essay

Endochondral Ossification. Most bones of the human skeleton are formed by endochondral ossification. During endochondral ossification, bone replaces a cartilaginous model of the bones. Chondrocytes (cartilage cells) lays down a cartilage model that is shaped like the future bones. As the cartilage model calcifies the chondrocytes die. Osteoblasts from the periosteum secrete the organic bone matrix that undergoes calcification. The result is an outer layer of compact bone called a bone collar which covers the diaphysis. Blood vessels bring osteoblasts into a region of the cartilage called the primary ossification center where they produce spongy bone. The spongy bone of the diaphysis is absorbed by Osteoclasts creating the

Osteoporosis is a disorder of bones that affects bones making them low in bone mass fragile and will lead to bone fracture. Bone fracture will easily occur as this disease cause the matrix inside the bone become weak and brittle.Bones can become so brittle due to activities such as coughing can cause fractures.According to Macgill (2015) the origin of the word osteoporosis explain the condition of ‘osteo’ is for bone and ‘porosis’ means porous that resulting in weakness. At this condition, the bone tissue is mineralized normally, but the production is not enough to preserve the normal skeletal architecture. 80% of women and 20% men of 28 million American are affected with the osteoporosis. Approximately, women with the age of 50 will develop osteoporosis. Thin bones are the cause of 1.5 million fractures a year. As in Malaysia, the statistic shows that osteoporosis related to fractured is the common health problem especially in elderly..

When a femur becomes osteoporotic, it is the outer layer of the bone around the epiphyses and diaphysis, which begins to thin. This is the compact bone. In the distal and proximal epiphyses there would also be a loss of the cancellous bone. This is where the spongy bone is. When a bone is osteoporotic, a person becomes more susceptible to suffering from a bone fracture. On an x-ray, an osteoporotic femur doesn’t look as dense as a normal femur x-ray. In some of them you can see the larger spaces that are made in the trabeculae of the bone. This is the part that has a spongy appearance. In a normal femur the spaces in the spongy bone are smaller and dense. In the osteoporotic bone, the spaces are larger, which makes the bone more fragile. It doesn’t have as strong of a structure as a normal bone would.

Generally, bone can be classified into two categories according to its structure, cortical (compact) and trabecular (cancellous or spongy) bone. Cortical bone is stiff, with 5–10% porosity, and it makes up approximately 80% of skeletal bone, including cuboidal bones, flat bones, and the ends of long bones. Cortical bone is much denser, stiffer, and stronger than trabecular bone. The average strength of a compact human bone was 105 MPa in a longitudinal compression test, and was 131 MPa in a transversal compression test. In the same experiment, the average longitudinal strength in tension was 53 MPa [39]. In contrast, the porosity of trabecular bone is approximately 50–95%, which is higher than that of cortical bones. The surface area of the

The skeletal system is made up of bones and joints. Bones are a dry dense tissue that is composed of calcium phosphorous and organic matter. The bones are protected and covered by a layer of fibrous connective tissue membrane called the periosteum (Brown, et al., 2015, p. 1547). There are two basic types of bone tissue: Compact Bone and Spongy Bone. Compact bones are dense smooth bones, while Spongy bones are composed of small needle-like pieces of bones and open space. Bones are then categorised according to the shape of the bone into four groups: long, short, flat and irregular. Long bones characteristically are typically longer then they are wide and generally have a shaft with heads at either ends e.g. the humerus. They are mainly compact bones. Short bones

The 2 types of cells are dependent on each other for production and linked in the process of bone remodeling. Osteoblasts not only secrete and mineralize osteoid but also appear to control the bone resorption carried out by osteoclasts. Osteocytes, which are terminally differentiated osteoblasts embedded in mineralized bone, direct the timing and location of bone remodeling. In osteoporosis, the coupling mechanism between osteoclasts and osteoblasts is thought to be unable to keep up with the constant microtrauma to trabecular bone. Osteoclasts require weeks to resorb bone, whereas osteoblasts need months to produce new bone. Therefore, any process that increases the rate of bone remodeling results in net bone loss over

There are approximately two hundred six bones in our body and they're essential in our life. Bones consists of osseous tissue, nervous tissue, and epithelial and muscle tissue. Examples are the femur, humerus, clavicle, and sternum. The bones have many different functions in our bodies, but basically, their main functions are to provide support and protection for the body. Bones provide a framework that supports our body and bones such as skull, vertebrae and rib cage try to prevent internal organs from injuries. Also, bones enable movement by providing points of attachment for muscles and they produce blood cells, also known as hematopoiesis in the red marrow. Lastly, bones store minerals, such as calcium and phosphorus for different cellular activities and store lipids in adipose cells of the yellow marrow as an energy reservoir. There are different shapes and textures of bones. Bones can be flat, such as scapula and sternum, or irregular like the sphenoid bone and vertebra. Also, bones can be short or long. Examples of short bones are the carpal bone and talus and long bones are ulna, femur, and radius. In terms of texture, bones can be compact or spongy. Compact bones are dense and heavy while spongy bones are porous and light. Both types of bones are connective tissues. Usually compact bones are the out layer of a bone and spongy bones are the internal portion of the bone.

Throughout a lifetime, old bone is removed (resorption) and new bone is added (formation) to the skeleton. During childhood and teenage years, new bone is added faster than old bone is removed. Consequently, bone become larger, heavier, and denser. Bone formation continues at a pace faster than resorption until peak bone mass, which is reached around age 30. After age 30, bone resorption slowly exceeds bone formation. In women, bone loss is most rapid in the first years after menopause but persists throughout the postmenopausal years. Based on year 2000 census data, it is estimated that 55% of people age 50 and older have either osteoporosis or low bone mass. The major risk

4. Pre-osteoblasts are recruited by cytokines: transforming growth factor beta, insulin growth-like factors, fibroblast growth factors and bone morphogenetic proteins (BMPs) (Hock et al, 2004). The actions of BMPs cause pre-osteoblasts to differentiate into osteoblasts (Monolagas, 2000). Osteoblasts then secrete bone matrix proteins: type-I collagen, osteocalcin, proteoglycans, growth factors and glycoproteins into the resorption pits (Nair et al, 1996). Approximately 50% of osteoblasts then undergo apoptosis and the remaining become embedded osteocytes or bone lining cells.

In the past decade, network television has been bombarded by crime shows attempting to make their mark on viewers. All of these programs—CSI, Lie to Me, Numb3rs, Law & Order—have the same general set up of a male lead with a hot-head who is complemented by his team of FBI agents. As a loyal viewer and fan of Bones, I often wonder what makes it stay afloat with so many shows out there like it. Could it be that Bones isn’t like any of the other crime shows? Through its crimes and unsolved murders, Bones helps its viewers make sense of the disastrous world around them. The world we live in is full of danger and unsolved crime, but after watching Dr. Brennan, her team of “squints” and Agent Booth solve even the most bizarre murders, the

Bone is a living organism that is continuously regenerating its self through two stages (formation and resorption). In the resorption stage old bone is broken down then removed by cells. Then in the formation stage, new bone is built to replace the old by cells called osteoclasts. When the human body is younger more bone is produced than removed and as the body grows in age it’s the opposite also known as primary osteoporosis since it isn’t caused by other condition or long time medication.

The balance between the activities of osteoblasts and osteoclasts is very important when it comes to the maintenance of bone health and strength; when osteoclasts remove calcium faster than osteoblasts can deposit it, bones become weaker.

Bone is a living tissue that is constantly breaking down and being replaced. Throughout life, our body balances the loss of bone with the creation of new bone. We reach our highest bone mass at about age 30.

Skeletisation of a dead body has made identification of the remains trickier. As humans, we become accustomed to recognise others from outer body appearances, not their insides. However, it is well established that morphological and metric changes occur on certain bones through a human's lifetime (e.g. Pelvis: Phenice, 1969, Skull: Meindl and Lovejoy, 1985, Long bones: France, 1998) making identification possible. To complicate matters, morphological and metric changes can differ within and between human population groups due to intrinsic and extrinsic factors (DiGangi and Moore, 2012). An example of this is nutritional deficiency, which effects males more than females and causes reduced sexual dimorphism (Ross, Baker and Falsetti, 2003). Recently, there has been a global trend to establish population specific standards for identification due to such variation. Compared to America, much of Europe and other areas have not had as much opportunity to conduct research on modern populations,

The bone mass in the skeleton reaches maximum density of age 30.” 206 bones made of the dust of the ground! These bones all come together with precision. All the joints are perfectly attached. Just think in the human foot there are 26 bones alone, with 33 joints, (20 of which are actively articulated), with more than a hundred muscles, tendons, and