Bone Cellular Components - Coursework Example

Bone Components By + Introduction A bone is a rigid tissue in the body made up of cells that arefixed together in a hard inter-cellular material. The two main components of this material that make up the bone include calcium phosphate and collagen (Davis 2004). These components distinguish bones from other tissues like the enamel, shell and chitin. Bones have tissues that make up individual bones of the human skeletal system and skeletons of other animals. Bones contain living tissues that possess their own blood vessels. These living tissues consist of living cells that help them to grow and repair themselves. There are about 300 soft bones in the human body (Davis 2004). During childhood cartilages grow and are slowly replaced by a hard bone. Some of the hard bones fuse in adulthood to form about 206 bones (Davis2004). Since the bone is a living tissue, it is very important to understand the structure and morphology of any bone. The knowledge of bones can be useful in detecting certain bone deformities and treating them. This paper discusses the general knowledge of bones and conditions that are associated with bones. 2. Bone functions There are three major categories of bone functions. They include; Mechanical Functions of bones: Protection: At various regions inside of the body, bones offer protections to vital and sensitive organs. Examples of these organs are the cerebrum and heart (Marieb 2006). Shape: due to their inflexible nature, bones provide a structure upon which muscles and other tissues of the body are assembled (Marieb 2006). Movement: the bone structure is the moving hardware of the body. The significant part of bones in development is that they act as levers in the body by utilizing the powers produced by skeletal muscles in a valuable manner (Marieb and Hoehn 2008). Synthetic Functions of Bones: Synthesis of platelets: Bones play a significant role in creating platelets. They provide a home for the bone marrow that has hematopoietic stem cells, fit for creating platelets. In babies, bone marrow of all long bones is equipped for this amalgamation, in any case, as an individual gets more seasoned (Marieb 2006). Metabolic Functions of Bones: Mineral Storage: Bones are a vital storage facility for minerals like calcium and phosphorus (Marieb and Hoehn 2008). Fat storage: the long bones have yellow bone marrows that act as a site for storing fat. Acid- base balance: the bone protects the blood from intemperate pH conditions by engrossing or discharging alkaline salts (Marieb and Hoehn 2008). 2.1. Types of Bones There are two major types of bones. They are classified according to the pattern of collagen forming the osteoid. They include: Woven bone- it is mechanically weak and is characterized by random organizations of collagen fibers (Rogers 2011). These bones are formed when osteoblasts produce osteoid swiftly. In adults, woven bone is formed when there is a rapid new bone formation. Lamellar bone- its characteristics include a regular parallel alignment of collagen into lamellae (Rogers 2011). It is mechanically weak. Following a fracture the woven bone remodels and is replaced by the lamellar bone. Other categories of bone classification include; Types on the basis of shape: Long bones These bones have two expanded ends called the epiphysis and an elongated shaft known as the diaphysis. Long bones can be divided into typical long bones, miniature long bones, and modified long bones (Seeley et al. 2006). Short bones As the name states, these bones are short in stature and can assume any shape. Their names come from their shapes. Examples include the scaphoid, trapezoid, and cuboid among others (Seeley et al. 2006). Flat bones They appear flat and have two prominent surfaces. Examples include the ribs and scapula (Seeley et al. 2006). Irregular bones As their name suggests, these bones completely lack a regular shape. An example is the hip bone. Pneumatic bones They have an irregular shape, but exhibit a slight difference with the irregular bones. They have large air spaces which make them light. An example is the ethmoid bone (Seeley et al. 2006). Sesamoid bones They are in form of nodules fixed in tendons and joints. They lack a periosteum. An example is the patella. Types on the basis of development: Membranous bones They are also known as dermal bones. They ossify from mesenchymal condensations. They are mostly bones of the face and the skull (Seeley et al. 2006). .Cartilaginous bones They undergo intra-cartilaginous ossification in order for them to be formed. They do not arise from the mesenchymal condensations (Goldman et al., 2005). An example is the thoracic cage. Membro-cartilaginous bones Their ossification is partly from the mesenchymal condensations and partly from the cartilage (Goldman et al., 2005). Examples include the mandible, the clavicle, and the temporal among others. Types on the basis of region: Bones of axial skeleton They form the structure of the axial skeleton of the human body. An example is the vertebral column. Bones of appendicular skeleton They form the structure of the appendicular skeleton. An example is the bones of the pelvic girdle (Goldman et al., 2005). 2.2 Bone Development – Ossification Ossification is a complex process by which bone formation occurs (Goldman et al., 2005). The process involves conversion of various connective tissues to form a bone. Based on the type of tissue converted into bone, the process of ossification involves the following steps; 2.2.1. Intramembreaneous ossification It involves the replacement of connective tissue membrane sheets with bone tissue and results in the formation of the flat bones for example the clavicle, the skull or the mandible (Goldman et al., 2005). 2.2.2. Endochondrial ossification It occurs when there is replacement of hyaline cartilage model with bone tissue, for example, the femur, humerus, radius, and radius (Goldman et al., 2005).Long bones continue to grow in grow in length and width all the way through childhood and adolescence. Bones increase in length because of increase in endotracheal formation. Increase in circumference of the bone shaft is achieved by the formation of new bone on the outer surface of the cortical bone. 2.3. Bone structure and composition The structure of a bone comprises of two tissues; The cortical bone. It is the hardest outer layer and is composed of strong, tough, and dense tissue (Parker 2007). The cancellous or trabecular bone is the innermost spongy layer. It is less dense than compact bone (Parker 2007). 2.3.1. Bone marrow The osteoid comprises of 94% type I collagen and non collagenous proteins. The rigidity and hardness of the bone are as result of mineral salts in the osteoid matrix that is comprise of a calcium and phosphate compound. Scientists suggest that a calcified bone has approximately 25% of organic matrix, 70% inorganic mineral, and 5% water (Parker 2007). 2.3.2. Bone cells Various cells in the human bone are in charge of maintaining, production, and modeling of these bones (Parker 2007). These cells include; Osteoblasts These cells come from the mesenchymal stem cells. Their function is mineralization and synthesis of matrix in the bones. Majority of bone surfaces in an adult human are lined by bone lining cells (Parker 2007). Osteocytes When osteoblasts become intergrated within newly formed osteoids, they form osteocytes. Osteocytes that are found in the bone matrix maintain contact with the recently formed osteocytes in osteoid, the osteoblasts and other cells lining on the bone surface through a rich network of cells (Parker 2007). Osteocytes function is to respond to any changes in physical forces being applied to the bone and to receive messages to cells on the bone surface, directing them to trigger formation processes. Osteoclasts They are large multinucleated cells that resemble macrophages. Their distinguishing characteristic is the ruffled edge that provides a surface for active resorption to occur. They are derived from the hematopoietic lineage. They are located on the surface of the bone to facilitate active resorption of mineralized tissue (Rogers 2011). 3. Classification of bone disorders Bone disorders have no clear method of being classified, but a combination of genetical analysis and phenotypical description has shown to increase researcher’s knowledge on the basic defects and etiologies associated with bones. Below is a guideline of how bone disorders are categorized. 3.1 Genetically inherited These bone disorders are passed on from parents to off springs through genes. 3.1.1. Achondroplasia (ACH) It is a genetic bone disorder where the bone forms without a cartilage. It normally associated with dwarfs with short limbs. When the process of ossification fails, it means that there will be no conversion of cartilage to bone. This is called achndroplasia. People with these conditions have short stature (Allgrove and Shaw 2009). Signs and symptoms Breathing problems, ear infections that recur and obesity. Short stature with lordosis or kyphosis (Allgrove and Shaw 2009) Complications Hydrocephalus Walking difficulties Treatment There is no actual treatment for dwarfism, but the underlying conditions can be managed( Allgrove and Shaw, 2009). 3.1.2 Brittle Bone Disease- Osteogenesis Imperfecta (OI) It is a disorder of the bone that is genetically inherited. People with this condition experience pathological fractures from time to time, despite the amount of force being applied on the bone (Allgrove and Shaw 2009). Diagnosis It is difficult to carry out a diagnosis of this order. However, the diagnosis can be done using a combination of taking a family history, biochemical testing, checking the medical and physical history (Allgrove and Shaw 2009). Treatment Treatment is multidimensional. Manage the pain, encourage exercise, and offer physical therapy. Biophosphate and pharmacological therapy can be included. 3.2. Nutritional Bone Disorders These are bone disorders that arise from deficits in the nutritional requirements of an individual. Some of the nutritional requirements include a diet rich in calcium and phosphorous or vitamin D (Allgrove and Shaw 2009). 3.2.1. Rickets in Children Rickets is a nutritional disorder caused by lack of calcium, phosphate or vitamin D. Rickets affects children in that their bones weaken and become soft, hence they develop a malformation in their bones. It affects mostly children of age between six and twenty four months (Allgrove and Shaw 2009). Signs and symptoms Pain in the bones, Dental deformities, delayed teeth formation, abnormal skeletal structure, impaired growth and other major bone deformities (Allgrove and Shaw 2009). Diagnosis It is done by taking a nutritional history, a physical exam and conducting an x-ray on the long bones. Blood analysis can also be done to determine the levels of calcium, phosphorous and blood urea nitrates (Allgrove and Shaw 2009). Treatment Treatment depends on the cause of the rickets. It includes offering calcium and phosphate therapy, exercises and having a balanced diet (Elam, 2013). 3.2.2. Osteomalacia (OM) This disorder occurs as a result of lack of enough vitamin D. the result is poor bone formation process that causes the bones to appear weak and soft (Elam 2013). Symptoms and signs Formation of weak muscles, bone pain that ranges from moderate to severe, changes in walking posture and impaired gripping abilities. Risk factors Lack of enough vitamin D due little exposure to sunlight Conditions that result in renal or hepatic failure, which interfere with vitamin D synthesis Some surgeries interfere with the digestive system and often result in malabsorption of vitamin D (Elam 2013). Treatment Administer oral or intramuscular calcium and vitamin D supplements to restore diminished vitamins and minerals (Elam, 2013). In case of an underlying condition, treat it first. 3.3. Autoimmune Disorders Autoimmune Disorders occur when the body’s immune system attacks its own tissues (Meyer 2009). 3.3.1. Rheumatoid Arthritis (RA) Rheumatoid Arthritis is an autoimmune disease in which the body’s immune system mistakenly attacks bone joints (Meyer 2009). It can also result into inflammations that in the end damage existing tissue bones. This disorder affects people of age between 30 and 60 (Meyer 2009). Symptoms Symptoms tend to vary from time to time. Common symptoms include pain at the joints, fatigue, red and swollen joints, especially at wrist and ankle (Meyer 2009). Treatment Rheumatoid has no specific cure but the symptoms can be managed, as they appear (Meyer 2009). 3.4. Degenerative Disorders Degenerative disorders are disorders that result in the deterioration of function and the structure of a body tissue (Meyer 2009). 3.4.1. Osteoarthritis (OA) It is a degenerative disease that affects mostly older people. It affects the cartilages at the end of long bones therefore, it inhibits the bones from gliding over each other at the joint (Meyer 2009). Signs and symptoms Pain in the joints, swellings in the joints, difficulty in walking or moving, and a feeling of stiff joints Diagnosis Diagnosis is done by taking a full clinical history, physical examination, x-rays, and magnetic resonance imaging (Meyer 2009). Treatment The goals of treatment are to minimize pain, improve joint motion and to maintain a normal healthy lifestyle (Meyer 2009). Treatment is done by surgery, drugs to control pain, exercise, weight control and enough rest. 3.4.2. Osteoporosis This is a disorder where the bones appear weak and porous. This weakness suggests that the bone cannot perform its normal functions. The disease progresses in a silent manner until the bones become extremely weak, porous, and painful (Meyer 2009). Risk factors They include; history of smoking, gender, especially female, low body weight and menopause. Treatment Physicians and nutritionists recommend vitamin D and calcium supplements with a combination of regular physical activities and a balanced diet. Pharmacological therapy can involve hormone replacement therapy. Complications Major complications include poor healing of fractures, pathological fractures, and joint dislocations. 3.5. Paget’s disease It is a bone disorder that affects the hearing systems. It is characterized by abnormal growth of bones that affect long bones. These abnormal bones cause injuries, fractures, and discomfort to the long bones (Vogiatzi 2009). Cause There is no exact cause of this disorder, but researchers believe that is strongly linked to inheritance. Alternatively, it can arise after a previous viral infection (Vogiatzi 2009). The bones affected include pelvic bones, the spine, the skull and long bones of the legs. Signs and symptoms Abnormal enlargement of bones, pain in the bones, dislocations and fractures, and lastly damaged cartilages Risk factors It affects a specific gender, especially male and another factor is aging. Diagnosis The common methods of diagnosis used include, x-rays, CT scans and blood tests. Treatment It involves pharmacological therapy, adequate physical activities and eating a balanced diet. 3.6. Bone Tumors Bone tumors can occur because of secondary metastatic lesions or primary malignancy (Vogiatzi 2009). Primary bone tumors have a better prognosis and lesser side effects because they are benign. Malignant primary tumors have a high rate of complications and develop the worst prognosis. Bone tumors are categorized based on the site they affect. Chondroblastoma It is a benign tumor that affects the terminal ends of long bones. It affects people younger than 25 years. It has no exact cause (Vogiatzi 2009). Sign and symptoms Development of weak muscles Staggering gait on the affected limb Rigid joints and muscle atrophy. Diagnosis It is difficult to identify this tumor using physical examination. The best methods of diagnosis include tissue biopsy, CT scans and X-rays. Secondary Bone tumors They are metastatic lesions that arise from other primary tumors. Cancers of the lung, breast and prostate tend to metastasize to bones. These tumors are managed based on the stage of the tumor. The most appropriate method of treatment is radiotherapy and chemotherapy (Vogiatzi 2009). 3.7. Hormonal Disorders These are bone disorders that arise due to failure of certain glands to synthesize hormones involved in the process of bone formation. A good example of a bone hormone disorder is the osteitis fibrosa cystic. Osteitis fibrosa cystic This disorder occurs because of too much secretion of certain hormones in the parathyroid gland that cause cysts in the bones (Vogiatzi 2009). Cause The cause is parathyroid secreting tumors. Symptoms Pain in the affected bone, increase in serum calcium levels, renal stones and bone deformities Diagnosis Physicians recommend using x-rays and blood analysis to determine the levels of calcium, alkaline phosphates, and phosphorous (Vogiatzi 2009). Treatment It is managed through surgery by removing the parathyroid gland. 3.8. Inflammatory Disorders Inflammatory disorders occur when a foreign antigen to create a reaction that often presents with redness, heat, swellings, and pain (Seeley et al. 2006) triggers the body’s immune system. Bones also undergo inflammation, especially under the following diseases; systemic lupus erythromatosus, rheumatoid arthritis, gout and ankolysing spondylitis. Treatment Its done by managing the presenting signs and symptoms 3.9. Fracture A fracture is defined as a break in the continuity of bones. Bones that mostly experience fractures are the long bones (Seeley et al. 2006). Other bones can also experience fractures. Signs and symptoms Severe pain, injury, swelling, a hematoma and limited range of movement Risk factors Other disorders like osteoporosis Recreational activities put one at risk of impacting the bones like football Continuous use of steroids Treatment The procedure used to manage a fracture depends on the type of bone, severity of fracture and the area of the fracture. Most bones are managed using immobilization. Open surgical reduction can also be used (Baker-LePain and Lane 2012). 3.10. Other musculoskeletal disorders 3.10.1. Muscular Dystrophy (MD) This is a group of diseases that result in continuous muscle weakness and loss of essential muscle mass (Baker-LePain and Lane 2012). It is characterized by certain mutations that alter the process of producing proteins that provide nutrients to the muscle. Symptoms can begin as early as early childhood. This condition can be severe to the extent of inhibiting movement. There is no cure for this condition (Baker-LePain and Lane 2012). Symptoms Muscle wasting, pain in the muscles, inability to walk, staggering gait and walking on toes. 3.10.2. Cerebral Palsy (CP) Cerebral palsy refers to disorders that impair ability of a person to control of movement because of damage or injury to the brain (Miller 2005). It develops at age 2 or 3. Luckily, cerebral palsy does not progress to the later stages of life if it is detected early and treated (Miller 2005). Causes Injuries to the brain Infections to the mother during pregnancy Severe cases of jaundice in children Oxygen deprivation to the brain that is severe (Miller 2005) Symptoms and signs Delayed walking, talking and crawling Delayed infant reflexes Inability to control the head Abnormal skeletal formation and stiffening of joints Seizures Treatment There is no known cure for cerebral palsy. However, the disabilities associated with this disorder can be reduced. Treatment can include rehabilitation, offering education to the parents and close monitoring for any other abnormal behaviors (Miller 2005). 3.10.3. Ankylosing Spondylitis Ankylosing Spondylitis is an inflammatory disorder that is chronic and it affects large joints, the sternum, and the spine (Marieb and Hoehn 2008). It is marked by a decrease in spine motion. People with this condition complain of lower back pain, limited motion, and bone stiffness in the morning (Marieb and Hoehn 2008). Treatment Treatment is by giving pain medication, balanced diet, regular exercises and enough rest. 4.0 Conclusion Bones are very important structures in our bodies. From the above explanations bones have very many important functions that are vital for the human body to function. Taking care of our bones is very important so that bone disorders are minimized. A bone is a very delicate structure if not well taken care of in terms of exercises, eating a balanced diet and going for regular physical examinations. The entire human body consists of at least a bone here or there. References Allgrove, J. and Shaw, N. (2009). Calcium and bone disorders in children and adolescents. Basel: Karger. Baker-LePain, J. and Lane, N. (2012). Role of bone architecture and anatomy in osteoarthritis. Bone, 51(2), pp.197-203. Davis, M. (2004). Human Physiology Interactions: Exploring the Functions of the Human Body. The American Biology Teacher, 66(2), pp.150-151. Goldman, H., Thomas, C., Clement, J. and Bromage, T. (2005). Relationships among microstructural properties of bone at the human midshaft femur. J Anatomy, 206(2), pp.127-139. Hotamisligil, G. (2006). Inflammation and metabolic disorders. Nature, 444(7121), pp.860-867. L. Elam, M. (2013). Evidence for Bone Reversal Properties of a Calcium- Collagen Chelate, a Novel Dietary Supplement. 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