...Bone is composed of two different components. Collagen which is a protein that creates the woven like framework. Collagen also helps bones become flexible. Bones are also made of Calcium, which strengths them. Osteoclasts are responsible for breaking down old bone, while osteoblasts are responsible for replacing them with new bones. Bone remodeling consists of removing the old bone and replacing it with new bone. There are three phases that occur during this process. Resorption, which is basically digestion of the old bone. Reversal, which is when mononuclear cells appear on the bone. And lastly, formation, when new bone is laid down until the old bone is finally replaced. These steps are crucial in the initial stages of life. In early development, bones are sculpted which allows new bone to grow at...
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...Bone is a living tissue that supports our muscles, protects vital internal organs, and stores most of the body's calcium. Bone also contains living cells, including some that nourish the tissue and others that control the process known as bone remodeling. Throughout life, our bones are constantly being renewed by means of this remodeling process, in which old bone is removed (bone resorption) and replaced by new bone (bone formation). Bone remodeling is carried out through the coordinated actions of bone-removing cells called osteoclasts and bone-forming cells called osteoblasts. Osteoblasts are mono-nucleated cells that synthesize bone. These cells are fully involved in the anabolic activity in bones. Osteoclasts are multinucleated cells responsible...
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...Yabut Anatomy and Physiology 200A Dr. Edward Eivers 2/14/16 Introduction: Normal Physiology of the Bone It is important to know the fundamental aspects of the skeletal system and the normal anatomy and physiology of the bone tissue in the system to understand osteoporosis. The skeletal system of the human body is essential in many functions, such as supporting body structure, storing minerals and bone growth factors, and being used as leverage for skeletal muscle locomotion. The skeletal system used to be made of hyaline cartilage, but the cartilage eventually ossifies into bone tissue as the body continues to age develop into adulthood. Bone growth and development is strongly affected by...
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...Chapter 6: Skeletal System: Bones and Bone Tissue Multiple Choice 1. Important functions of the skeletal system include A) protection of the brain and soft organs. B) storage of water. C) production of Vitamin E. D) regulation of acid-base balance. E) integration of other systems. Answer: a Level: 1 2. A band of connective tissue that attaches a muscle to a bone is a(n) A) aponeurosis. B) ligament. C) bursa. D) epimysium. E) tendon. Answer: e Level: 1 3. Ligaments attach A) muscle to muscle. B) bone to bone. C) muscle to bone. D) nerve to bone. E) nerve to muscle. Answer: b Level: 1 4. Chondroblasts produce A) ligaments. B) cartilage matrix. C) bone tissue. D) blood cells. E) synovial fluid. Answer: b Level: 1 5. The type of cartilage associated with bone function and development is A) elastic cartilage. B) fibrocartilage. C) hyaline cartilage. D) interstitial cartilage. E) osteocartilage. Answer: c Level: 1 6. The connective tissue sheath of cartilage is called the A) matrix. B) chondrocyte. C) ligamentous cord. D) lacuna. E) perichondrium. Answer: e Level: 1 7. Cartilage A) is composed of osteons. B) is surrounded by a membrane called the periosteum. C) contains chondrocytes located in lacunae. D) does not need nutrients and oxygen so it has no blood vessels. E) is well vascularized. Answer: c Level: 1 8. Proteoglycan molecules in the matrix of cartilage A) replace collagen fibers in the matrix...
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...Medications That Affect Bone Mineral Density Drug-induced osteoporosis is common and may result in significant morbidity and mortality for patients. The World Health Organization (WHO) has defined osteoporosis as bone density less than 2.5 standard deviations (SD) of the mean gender-matched, young healthy population (T-score at or below -2.5). Osteopenia is defined as loss of bone with T-score between -1 and -2.5.1 Many drugs have the potential to decrease bone mineral density (BMD). TABLE 1 lists the agents discussed in this lesson. Most of the disease states that are treated with these drugs also predispose the patient to low BMD, so the medication may be adversely affecting an already compromised bone structure.2 The most significant consequence of low BMD is a fracture.3 [pic] Bones provide support for movement, protect vital organs, and are the largest repository for calcium and other minerals.3 Ninety percent of the body's calcium is in the skeleton.4 Bone is constantly being remodeled, with old bone being resorbed and new bone forming.4,5 The rate of annual calcium turnover is 100% in infants and 18% in adults. The cycle of bone resorption and consequent formation is approximately 100 days.4 Process of Bone Remodeling Bone remodeling is a complex, highly orchestrated process involving the balance of many factors. The cycle of bone remodeling occurs in stages, beginning with the formation of osteoclasts, bone resorption (by osteoclasts), a reversal period, bone matrix formation...
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...Bone turnover is carried out by osteoclasts, cells that resorb old bone, and osteoblasts, cells that lay down new bone matrix. Osteoclasts are large multi-nucleated cells derived from mononuclear hematopoietic cells that, upon stimulation, secrete lysosomal enzymes during bone resorption. Bone is resorbed by acidification and proteolysis of the collagen bone matrix and hydroxyapatite crystals [8]. Osteoblasts evolve from mesenchymal stem cell (MSC) lineage, along with adipocytes, chondrocytes, myoblasts and fibroblasts. Bone formation takes place in three stages: 1) production of osteoid matrix, 2) maturation of osteoid matrix, and 3) mineralization of the matrix. After the completion of bone formation, osteoblasts assume one of three fates: 1) undergo apoptosis, 2) remain on the bone surface as bone lining cells, or 3) are buried in the newly formed bone matrix as terminally differentiated osteocytes....
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...Bone formation also known as ossification and osteogenesis, is the process by which bone tissue replaces with fibrous or cartilage structure to form the bony skeleton to early childhood to adulthood. It takes about 8 weeks or so, for the bone tissue to begin developing in the fetal state. In addition, as the body grows so does the bone in thickness and length, this is called bone growth. There are multiple of factors influencing bone development, growth, and repair. These include nutrition, exposure to sunlight, hormonal secretions, and physical exercise. (p 183-198) Nutrion: Calcium is the most abundant mineral in the bone and constitute its structure and strength, it is vital for muscle contraction and nerve transmission, besides other roles. Magnesium is needed for bone structure and strength, (Integration.”)Trace minerals are also important for encouraging bone growth in lesser amount. These type of nutrition helps to maintain and balance vitamin D in the body between bone resorption and formation, the two key processes of bone remodeling. Vitamins and minerals, also help bone formation, strength and mineralization, and decrease the risk of bone fractures. It helps harden bone. promotes bone growth, protects vitamin D levels and contributes to calcium absorption....
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...2.1 Bone classification and its cellular structure There are two major types of bone. They denote different stages of a bone lifecycle. 1. Woven Bone – It is an unorganized and premature bone that is found in either growing bones or at fracture sites as newly-formed bone. 2. Lamellar Bone – It is a mature bone that results from the further remodeling of woven bone. Lamellar bone may be further divided into: a. Cortical Bone – It is a dense or compact bone, which constitutes approximately 80% of the skeleton. It is approximately 20% porous and consists of a dense bundle of vascular channels containing blood vessels surrounded by mature bone. It forms the middle 80% of long bones of the body – tibia, fibula in the lower leg, femur in the upper leg, the radius and ulna in the lower arm, and the humerus in the upper arm. b. Cancellous Bone – It is a spongy bone, which constitutes approximately 20% of the skeleton. It is approximately 70% porous, highly vascularized and consists of loosely formed matrix of beams designed to withstand the principal stresses and strains applied to the bone. The density of cortical bone is four to six times higher than cancellous bone. Cancellous bone constitutes the remaining 20% of bone located at the ends of the long bones and predominates in the pelvis and the 33 vertebrae from the neck to the tailbone. A fibrous membrane called the periosteum covers bone. In general, bone constitutes minerals, proteins, hormones, water, other molecules...
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...Musculoskeletal Pathophysiology Bones Bone remodeling Minerals have to be deposited into the bones and to be remodeled Osteoblasts = builds the bone Osteoclasts = corroding the bone, originate from stem cell * Big cells, a number of nuclei * Ruffled edges to increase surface area * Mineral resorption (dissolves crystals and releases minerals into the blood) * Acid dissolves the bone minerals Things can do wrong * Preventing bones from generating in other parts of the body * Inhibitors include hydroxyapatite crystal deposition and thus not calcify * Calcification of arteries SMC (Smooth muscle cells) in calcification Media Contractile phenotype Low proliferation, low synthesis, expression of SMC markers Intima Synthetic phenotype Proliferative, migratory, secretory Osteoblast-like phenotype Mineralising, expression of osteoblast markers It is more common to have hypocalcemia than hypercalcemia Common cause of hypercalcemia is thyroid tumour Calcium homeostasis * Controlled by 3 hormones: calcitriol, calcitonin and PTH (parathyroid hormone) Calcium is not strong/high enough weak bones Calcium into blood from our bones (99% Ca stored) * Two hormones to tell osteoclast to reabsorb Ca out of the bones and back into the blood (PRH and Calcitriol) or redeposited into the bones via osteoblast * Adults have low levels of calcitonin (children have higher levels since their bones are still forming, stronger effect...
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...cartilage that is needed to replace bone and to increase length of the bone. The point where the primary and secondary ossification centers meet is called the epiphyseal line. Secondary ossification occurs after birth for postnatal bone growth and continues until skeletal maturity. As bones increased in length, they are also increasing in diameter. Appositional growth, is the growth in diameter continues after longitudinal growth stops. Osteoclasts resorb old bone...
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...spongy bone. Compact bone is dense bone with very few spaces and is covered by a nourishing membrane called the periosteum. Spongy bone is identified by its many spaces that are filled with red bone marrow, which produces red blood cells. 3. Describe the structure of a long bone. Where are the yellow and red marrow found in adults? A long bone in the human body contains both compact bone and spongy bone. The compact bone is found on the outer surface of the bone and compose the shaft. The spongy bone is found at the ends of the long bone. Yellow bone marrow it found in the central shaft of the long bone surrounded by the compact bone. Red bone marrow is found in spaces of the spongy bone. 4. Describe the structure of an osteon, and explain the function of osteocytes and the central canal. The osteon consists of a central canal surrounded by concentric rings of osteocytes (mature bone cells) in a rigid matrix. O steocytes are located within a lacuna in the matrix. Canals connect the lacunae to each other and to the central canal. This allows for the transport of items between the cells and the blood vesels in the central canal. 5. Describe the formation of bone in a fetus. Explain how bone growth continues after birth. During fetal development, most of the skeleton is first formed of cartilage. Cartilage cells actively divide, allowing the skeleton to grow as the fetus does. Beginning around the third month of development, osteoblasts (bone-forming...
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...Health 1: Electronic literature Search Bone Formation Absence of bone sialoprotein (BSP) impairs primary bone formation and resorption: the marrow ablation model under PTH challenge. Wade-Gueye NM, Boudiffa M, Vanden-Bossche A, Laroche N, Aubin JE, Vico L, Lafage-Proust MH, Malaval L. Source: INSERM U1059/SFR IFRESIS, F42023, Saint-Etienne, France. Abstract: Bone sialoprotein (BSP) is highly expressed in early bone deposition and may play a part in primary bone mineralization. We previously showed that while BSP−/− mice have a mild secondary bone phenotype and are responsive to mechanical (unloading) and hormonal (ovariectomy, parathyroid hormone (PTH)) challenges, repair of a cortical bone defect, which involves primary bone deposition is significantly delayed in these mice. In the present study, we investigated the role of BSP in a pure model of primary bone modeling. Bone marrow was ablated by trans-epiphysis aspiration in the femora of BSP+/+ and BSP−/− mice, and 7 days post surgery μCT analysis showed vigorous new bone formation in the shaft of BSP+/+ animals but much less in BSP−/− mice. After 14 days, the volume of medullary bone was significantly decreased as expected in BSP+/+ mice, while it remained stable in the BSP−/−. Osteoid thickness and surface were higher in BSP−/− at day 7, suggesting delayed mineralization, while osteoclast surface and number were significantly lower at day 14, a stage of high medullary bone resorption. At day 7, mRNA expression...
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...system: made of connective tissue: * Bone: hard inorganic matrix of calcium salts * Compact: forms shaft and ends contain marrow space * Spongy: trabeculae * Cells: osteoblast, osteocytes, osteoclasts * Types: long, flat, irregular * Osteons/haversian system: cellular arrangement * Periosteum: CT covering (periosteum means around the bone itself) Structure of bone: *Ends of bone epiphysis inter bone is diaphysis Cartilage and ligaments: * Cartilage * Function: support * Types: fibrocartilage, hyaline, and elastic cartilage (find examples) * Ligaments: attach bone to bone Bone Development: * Prenatal: cartilage model * Fetus: some conversion to bone * Childhood: primary and secondary ossification sites formed * Adolescence: cartilage growth plate elongates Mature bone remodeling and repair: * Changes in shape, size strength * Dependent on diet, exercise, age * Bones cells regulated by hormones * Parathyroid hormone (PTH): removes calcium from bone * Calcitonin: adds calcium to bone * Repair: hematoma and callus formation If you break a bone hematoma forms then a callus forms around it Functions of the skeletal system: * Protection: encases most internal organs * Support: allows body positions * Permit movement: muscle attachments for movement * Mineral reservoir: calcium, phosphorus 206 bones skeletal divided into 2 areas appendicular...
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...The skeletal system is made up of 206 bones. There are many conditions and diseases that can affect our bones, short term and long term, including; arthritis, osteoporosis and bone cancer just to name a few. “Bones, tendons, ligaments and cartilage make up the skeletal system. …The skeletal system protects the internal organs such as the brain and heart,” says Aubri John of the Live Strong organization. One disease that affects the skeletal system is arthritis. Arthritis is commonly found in elderly people because as the body ages the bones start to become more brittle. “The breakdown of cartilage in this form of arthritis leads to the bones rubbing together, causing stiffness, pain and eventual loss of movement in the joint…The cause of arthritis...
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...Kaemia Howard (19075564) Anatomy and Physiology The Aging Musculoskeletal System At the age of 84, your bones have taken a toll throughout your life time. This leaves you susceptible to a few bone diseases. Three of the most common diseases are Osteoporosis, Osteoarthritis and Muscular Atrophy. With Osteoporosis, it is a disease in which bones become fragile and more likely to fracture. Usually the bone loses density, which measures the amount of calcium and minerals in the bone. Since our bones undergo bone remodeling quite often in the younger years we do not think of the potential or likelihood of being diagnosed with Osteoporosis or Osteoarthritis. However as we age our bones do not recover and remodel as fast, causing loss of bone density. The more mass that is “banked” when younger leads to the smaller risk of having the disease. Much like Osteoporosis is Osteoarthritis. The more wear and tear you put on your bones and joints the more susceptible you are to Osteoarthritis. With these disorders maintain a popular quo among the elderly; the future diagnosis is almost certain to happen. An 84 year old thin female has more than likely already been diagnosed with one of the two disorders, if not both. Osteoarthritis can be very painful and can on more than one occasion hinder any plans that have been set forth, from a trip to the grocery store or an entire vacation. This is especially true of those who have the arthritis in their hands, fingers and knees. The final...
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