3. Major Constituents of a BoneThe ends of a long bone are called the epiphyses(singular, epiphysis), which are covered by a layer ofhyaline cartilage called the articular cartilage and articulate with other bones. The internal area of theepiphyses contains red bone marrow where erythrocytes (red blood cells), leukocytes (white bloodcells), and thrombocytes (platelets) are produced. The shaft of a bone is called the diaphysis. Thediaphysis contains an internal medullary cavity that is lined by the endosteum and usually filled withyellow marrow, where fat is stored. Except for the articular cartilage, a bone is covered by a tough outermembrane called the periosteum.In children, an epiphyseal plate of hyaline cartilage separates the epiphysis and diaphysis. It allows forgrowth in length. The epiphyseal plate will eventually ossify, at which point bone growth will stop. 4. Parts of Haversian system
Osteon-Is the basic unit of structure of compact bone, comprising a Haversian canal and itsconcentrically arranged lamellae.Osteocyte- an osteoblast that has become embedded within the bone matrix, occupying a bone lacunaand sending, through the canaliculi, slender cytoplasmic processes that make contact with processes ofother osteocytes.Canaliculi- Also known as lacrimal ducts, these tube-like structures carry the tears from the eyes to thelacrimal sac.Haversian Canal- any of the anastomosing channels of the haversian system in compact bone, containingblood and lymph vessels and nerves 5. List and describe the function of the three major types of cells found in bones.Bone is formed by three primary cell types:Osteoblasts:Osteoblasts are bone-forming cells that descend from osteoprogenitor cells. They form a proteinmixture known as osteoid, which mineralizes to become bone. Osteoid is primarily composed ofType I collagen. Osteoblasts also manufacture hormones, such as prostaglandins, to act on thebone itself. They robustly produce alkaline phosphatase, an enzyme that has a role in themineralization of bone, as well as many matrix proteins. Osteoblasts are the immature bone cells,and eventually become entrapped in the bone matrix to become osteocytes, which are the maturebone cells. All bone lining cells are osteoblasts.Osteocytes:Osteocytes are mature bone cells that originate from osteoblasts, which have migrated into andbecome trapped and surrounded by bone matrix, produced by themselves. The spaces theyoccupy are known as lacunae. Osteocytes have many processes that reach out to meet osteoblastsand other osteocytes probably for the purposes of communication. Their functions includeformation of bone, maintenance of matrix and homeostasis of Calcium.Osteoclasts:Osteoclasts are the cells responsible for bone resorption and remodelling. They are large,multinucleated cells located on bone surfaces in what are called Howship’s lacunae or resorptionpits. These lacunae, or resorption pits, are left behind after the breakdown of the bone surface.Because the osteoclasts are derived from a monocyte stem-cell lineage, they are equipped withphagocytic-like mechanisms similar to circulating macrophages.
and/or fibrocartilage. Finally, for the diarthroses joint, its structural name is the synovial joint,and it is considered freely movable, just like your shoulder joint. They are the body’s mostmobile joints, most numerous joints, and the most complex joints. 13. Identify the types of movement at synovial joints and give examples of specific joints where each occurs.The first type of movement classification is called the uniaxial joint. An example of one is theelbow joint; it is attached around one axis and in on certain place. Also, the first two cervicalvertebrae of the spine use the rotation method but are still considered uniaxial because our neckis given the ability to turn side to side, and up and down due to that joint. The second type ofmovement classification is the Biaxial joint. This joint in the body can be found in the thumbjoint between the first metacarpal and carpal bone, as well as the joint between the radius and thecarpal bones. The biaxial joint has two axes, and is perpendicular to each other, while being intwo planes. The third movement classification is the multiaxial joint. This joint has multipleaxes, for example the shoulder joint, and the vertebral joints. Questions to the Editor: 1.) Cancer treatment may generate a need for a bone marrow transplant. Osteoporosis is a condition characterized by an excessive loss of calcium in bone. These 2 conditions are disruptions or failures of 2 bone functions. Identify these 2 functions and explain what their normal function should be. A: One condition is called Hematopoiesis which is normally responsible for the formation of blood cells in the bone marrow. Another condition is called Mineral Storage which is normally responsible for maintaining equilibrium in the amount of calcium in the blood. 2.) Explain why a bone fracture along the epiphyseal plate may have serious implications among children and young adults. A: This is the most common fracture due to the location of the epiphyseal plate which is at the end of the long bone. This area is growing throughout young adult and child years, so because it is growing throughout these years, the fracture wont harden and heal right away causing serious symptoms. 3.) During the aging process, adults face the issue of a changing skeletal framework. Describe these changes and explain how these skeletal framework changes affect the health of older adults. A: During growth, bones and their connectedness lessen causing a weaker skeletal framework. Adult need to take nutrients and vitamins in order to strengthen their growing bones and prevent fractures.