Submitted by Editor
ESTIMATION OF CONTENT OF BONE ASH
PROJECT SUBMITTED BY
Department of Chemistry
This is to certify that the Chemistry project __________________________
__________________________________________ in Chemistry had been
Submitted by the candidate _________________________________
With roll number __________________ for the class XII practical examination of
the Central Board of Secondary Education in the year 2009.
It is further certified that this project is the individual work of the
I thank the staff of the Chemistry department for the help
And guidance provided to me in completing the project in
Chemistry. I also thank the principal for permitting the use of the
Resources of the school for completing the project.
Name of the Candidate:
|Bone - Introdution||6|
|Types of Bones||13|
|Paracrine Cell Signalling||17|
|Report of the project||19|
This project introduces some knowledge about the basics involved in finding the constituents of bone. This Project deals with the principle of qualitative analysis of cation and anion.
Skeletal system plays an integral part of most of the animals what is that it makes it form an integral part? The solution of this can be understood more clearly from this project.
Significance of project:
This project indeed would be a revolution in the world where there is increasing worry about problems of bone like osteoporosis and in this industrial age amount of calcium content in bone is also reducing; this project would indeed be a very good solution.
Bones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue. Because bones come in a variety of shapes and have a complex internal and external structure they are lightweight, yet strong and hard, in addition to fulfilling their many other functions. One of the types of tissue that makes up bone is the mineralized osseous tissue, also called bone tissue, that gives it rigidity and a honeycomb-like three-dimensional internal structure. Other types of tissue found in bones include marrow, endosteum and periosteum, nerves, blood vessels and cartilage. There are 206 bones in the adult human bodyand 270 in an infant
Bones have eleven main functions:
The primary tissue of bone, osseous tissue, is a relatively hard and lightweight composite material, formed mostly of calcium phosphate in the chemical arrangement termed calcium hydroxylapatite (this is the osseous tissue that gives bones their rigidity). It has relatively high compressive strength but poor tensile strength of 104-121 MPa, meaning it resists pushing forces well, but not pulling forces. While bone is essentially brittle, it does have a significant degree of elasticity, contributed chiefly by collagen. All bones consist of living and dead cells embedded in the mineralized organic matrix that makes up the osseous tissue.
Individual bone structure
Bone is not a uniformly solid material, but rather has some spaces between its hard elements.
Compact bone or (Cortical bone)
The hard outer layer of bones is composed of compact bone tissue, so-called due to its minimal gaps and spaces. This tissue gives bones their smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an adult skeleton. Compact bone may also be referred to as dense bone.
Filling the interior of the bone is the trabecular bone tissue (an open cell porousnetwork also called cancellous or spongy bone), which is composed of a network of rod- and plate-like elements that make the overall organ lighter and allowing room for blood vessels and marrow. Trabecular bone accounts for the remaining 20% of total bone mass but has nearly ten times the surface area of compact bone. If for any reason there is an alteration in the strain to which the cancellous subjected there is a rearrangement of the trabeculae. Although adult bone exists in both cancellous and compact forms, there is no microscopic difference between the two.
There are several types of cells constituting the bone;
The majority of bone is made of the bone matrix. It has inorganic and organic parts. Bone is formed by the hardening of this matrix entrapping the cells. When these cells become entrapped from osteoblasts they become osteocytes.
The inorganic is mainly crystalline mineral salts and calcium, which is present in the form of hydroxyapatite. The matrix is initially laid down as unmineralised osteoid (manufactured by osteoblasts). Mineralisation involves osteoblasts secreting vesicles containing alkaline phosphatase. This cleaves the phosphate groups and acts as the foci for calcium and phosphate deposition. The vesicles then rupture and act as a centre for crystals to grow on.
The organic part of matrix is mainly composed of Type I collagen. This is synthesised intracellularly as tropocollagen and then exported, forming fibrils. The organic part is also composed of various growth factors, the functions of which are not fully known. Factors present includeglycosaminoglycans, osteocalcin, osteonectin, bone sialo protein, osteopontin and Cell Attachment Factor. One of the main things that distinguishes the matrix of a bone from that of another cell is that the matrix in bone is hard.
Woven or lamellar
Two types of bone can be identified microscopically according to the pattern of collagen forming the osteoid (collagenous support tissue of type I collagen embedded in glycosaminoglycan gel
1) woven bone characterised by haphazard organisation of collagen fibers and is mechanically weak, and
2) lamellar bone which has a regular parallel alignment of collagen into sheets (lamellae) and is mechanically strong.
Woven bone is produced when osteoblasts produce osteoid rapidly which occurs initially in all fetalbones (but is later replaced by more resilient lamellar bone). In adults woven bone is created afterfractures or in Paget's disease. Woven bone is weaker, with a smaller number of randomly oriented collagen fibers, but forms quickly; it is for this appearance of the fibrous matrix that the bone is termedwoven. It is soon replaced by lamellar bone, which is highly organized in concentric sheets with a much lower proportion of osteocytes to surrounding tissue. Lamellar bone, which makes its first appearance in the fetus during the third trimester, is stronger and filled with many collagen fibers parallel to other fibers in the same layer (these parallel columns are called osteons). In cross-section, the fibers run in opposite directions in alternating layers, much like in plywood, assisting in the bone's ability to resist torsion forces. After a fracture, woven bone forms initially and is gradually replaced by lamellar bone during a process known as "bony substitution."
These terms are histologic, in that a microscope is necessary to differentiate between the two.
There are five types of bones in the human body: long, short, flat, irregular and sesamoid.
Lamellar bone requires a relatively flat surface to lay the collagen fibers in parallel or concentric layers.
The formation of bone during the fetal stage of development occurs by two processes: Intramembranous ossification and endochondral ossification.
Intramembranous ossification mainly occurs during formation of the flat bones of the skull; the bone is formed from mesenchyme tissue. The steps in intramembranous ossification are:
Endochondral ossification, on the other hand, occurs in long bones, such as limbs; the bone is formed from cartilage. The steps in endochondral ossification are:
Endochondral ossification begins with points in the cartilage called "primary ossification centers." They mostly appear during fetal development, though a few short bones begin their primary ossification after birth. They are responsible for the formation of the diaphyses of long bones, short bones and certain parts of irregular bones. Secondary ossification occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones. The diaphysis and both epiphyses of a long bone are separated by a growing zone of cartilage (the epiphyseal plate). When the child reaches skeletal maturity (18 to 25 years of age), all of the cartilage is replaced by bone, fusing the diaphysis and both epiphyses together (epiphyseal closure).
Bone marrow can be found in almost any bone that holds cancellous tissue. In newborns, all such bones are filled exclusively with red marrow, but as the child ages it is mostly replaced by yellow, or fatty marrow. In adults, red marrow is mostly found in the marrow bones of the femur, the ribs, the vertebrae and pelvic bones.
Remodeling or bone turnover is the process of resorption followed by replacement of bone with little change in shape and occurs throughout a person's life. Osteoblasts and osteoclasts, coupled together via paracrine cell signalling, are referred to as bone remodeling units.
The purpose of remodeling is to regulate calcium homeostasis, repair micro-damaged bones (from everyday stress) but also to shape and sculpture the skeleton during growth.
The process of bone resorption by the osteoclasts releases stored calcium into the systemic circulation and is an important process in regulating calcium balance. As bone formation actively fixes circulating calcium in its mineral form, removing it from the bloodstream, resorption actively unfixes it thereby increasing circulating calcium levels. These processes occur in tandem at site-specific locations.
Repeated stress, such as weight-bearing exercise or bone healing, results in the bone thickening at the points of maximum stress (Wolff's law). It has been hypothesized that this is a result of bone's piezoelectric properties, which cause bone to generate small electrical potentials under stress.
Paracrine cell signalling
The action of osteoblasts and osteoclasts are controlled by a number of chemical factors which either promote or inhibit the activity of the bone remodelling cells, controlling the rate at which bone is made, destroyed or changed in shape. The cells also use paracrine signalling to control the activity of each other.
Osteoblasts can be stimulated to increase bone mass through increased secretion of osteoid and by inhibiting the ability of osteoclasts to break down osseous tissue.
Bone building through increased secretion of osteoid is stimulated by the secretion of growth hormone by the pituitary, thyroid hormone and the sex hormones (estrogens and androgens). These hormones also promote increased secretion of osteoprotegerin. Osteoblasts can also be induced to secrete a number of cytokines that promote reabsorbtion of bone by stimulating osteoclast activity and differentiation from progenitor cells. Vitamin D, parathyroid hormone and stimulation from osteocytes induce osteoblasts to increase secretion of RANK-ligand and interleukin 6, which cytokines then stimulate increased reabsorbtion of bone by osteoclasts. These same compounds also increase secretion ofmacrophage colony-stimulating factor by osteoblasts, which promotes the differentiation of progenitor cells into osteoclasts, and decrease secretion of osteoprotegerin.
The rate at which osteoclasts resorb bone is inhibited by calcitonin and osteoprotegerin. Calcitonin is produced by parafollicular cells in thethyroid gland, and can bind to receptors on osteoclasts to directly inhibit osteoclast activity. Osteoprotegerin is secreted by osteoblasts and is able to bind RANK-L, inhibiting osteoclast stimulation.
|Rib Bone||2 Pieces|
|Test Tube||7 nos|
|Evaporating Dish||1 no|
|Ring Stand||1 no|
|Bunsen Burner||1 no|
|Test Tube Holder||2 nos|
|Dil. Nitric Acid||200 ml|
|1% Ammonium Hydroxide||100 ml|
|1% Silver Nitrate||25 ml|
|1% Ammonium Chloride||50 ml|
|Acetic Acid||100 ml|
|1% Potassium Thiocyanate||25 ml|
|Distilled Water||As Reqd|
Report of Project
||Yellowish white precipitate was obtained|
||On adding Nitric acid the ash sparingly dissolved|
||The pH was made to 8.6 Whitish brown precipitate of Magnesium ammonium phosphate was obtained|
||White precipitate of Silver chloride was obtained|
||White residue of calcium|
||Carbonate was obtained|
||Red colour solution marking the presence of Iron was obtained|
Extrapolation from the above observations
Constituents of bone ash identified were:
Apart from this Calcium and Phosphate which is found maximum in bone was estimated from the precipitate got. This was done by weighing the precipitate
There are many disorders of the skeleton. One of the more prominent is osteoporosis.
Osteoporosis is a disease of bone, leading to an increased risk of fracture. In osteoporosis, the bone mineral density (BMD) is reduced, bone microarchitecture is disrupted, and the amount and variety of non-collagenous proteins in bone is altered. Osteoporosis is defined by the World Health Organization (WHO) in women as a bone mineral density 2.5 standard deviations below peak bone mass (20-year-old sex-matched healthy person average) as measured by DXA; the term "established osteoporosis" includes the presence of a fragility fracture. Osteoporosis is most common in women after the menopause, when it is called postmenopausal osteoporosis, but may develop in men and premenopausal women in the presence of particular hormonal disorders and other chronic diseases or as a result of smoking and medications, specifically glucocorticoids, when the disease is called steroid- or glucocorticoid-induced osteoporosis (SIOP or GIOP).
Osteoporosis can be prevented with lifestyle advice and medication, and preventing falls in people with known or suspected osteoporosis is an established way to prevent fractures. Osteoporosis can be treated with bisphosphonates and various other medical treatments.
Other disorders of bone include:
The study of bones and teeth is referred to as osteology. It is frequently used in anthropology, archeology and forensic science for a variety of tasks. This can include determining the nutritional, health, age or injury status of the individual the bones were taken from. Preparing fleshed bones for these types of studies can involve maceration - boiling fleshed bones to remove large particles, then hand-cleaning.
Typically anthropologists and archeologists study bone tools made by Homo sapiens and Homo neanderthalensis. Bones can serve a number of uses such as projectile points or artistic pigments, and can be made from endoskeletal or external bones such as antler or tusk.
Alternatives to bony endoskeletons
There are several evolutionary alternatives to mammillary bone; though they have some similar functions, they are not completely functionally analogous to bone.
Bone penetrating the skin and being exposed to the outside can be both a natural process in some animals, and due to injury:
Several terms are used to refer to features and components of bones throughout the body:
|articular process||A projection that contacts an adjacent bone.|
|articulation||The region where adjacent bones contact each other — a joint.|
|canal||A long, tunnel-like foramen, usually a passage for notable nerves or blood vessels.|
|condyle||A large, rounded articular process.|
|crest||A prominent ridge.|
|eminence||A relatively small projection or bump.|
|epicondyle||A projection near to a condyle but not part of the joint.|
|facet||A small, flattened articular surface.|
|foramen||An opening through a bone.|
|fossa||A broad, shallow depressed area.|
|fovea||A small pit on the head of a bone.|
|Labyrinth||A cavity within a bone.|
|line||A long, thin projection, often with a rough surface. Also known as a ridge.|
|malleolus||One of two specific protuberances of bones in the ankle.|
|meatus||A short canal.|
|process||A relatively large projection or prominent bump.(gen.)|
|ramus||An arm-like branch off the body of a bone.|
|sinus||A cavity within a cranial bone.|
|spine||A relatively long, thin projection or bump.|
|suture||Articulation between cranial bones.|
|trochanter||One of two specific tuberosities located on the femur.|
|tubercle||A projection or bump with a roughened surface, generally smaller than a tuberosity.|
|tuberosity||A projection or bump with a roughened surface.|
- Otto, Towle, Crider
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