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ESTIMATION OF

CONTENT OF

BONE ASH

PROJECT SUBMITTED BY

Prashanth.G

12 D

ROLL NO: 0000000000000000

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Department of Chemistry

Bonafide Certificate

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

Candidate.

Signature: Date:

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INDEX

 - Bone - Introdution CONTENTS PAGE NO - Functions - Characteristics - Cellular Structure - Molecular Structure - Types of Bones - Formation - Re-Modelling 

• Paracrine Cell Signalling - Experiment Analysis
  • Report of the project - Results - Disorders - Osteology - Terminology 23, - Bibliography

Abstract

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 :

 Deals with analysis of bone ash

 Provides all basic ideas about concentration of various salts

present

 Provides information about ion exchange reaction

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.

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Functions Bones have eleven main functions: Mechanical  Protection — Bones can serve to protect internal organs, such as the skull protecting the brain or the ribs protecting the heart and lungs.  Shape — Bones provide a frame to keep the body supported.  Movement — Bones, skeletal muscles, tendons, ligaments and joints function together to generate and transfer forces so that individual body parts or the whole body can be manipulated in three-dimensional space. The interaction between bone and muscle is studied in biomechanics.  Sound transduction — Bones are important in the mechanical aspect of overshadowed hearing. Synthetic  Blood production — The marrow, located within the medullary cavity of long bones and interstices of cancellous bone, produces blood cells in a process called haematopoiesis. Metabolic  Mineral storage — Bones act as reserves of minerals important for the body, most notably calcium and phosphorus.  Growth factor storage — Mineralized bone matrix stores important growth factors such as insulin- like growth factors, transforming growth factor, bone morphogenetic proteins and others.  Fat Storage — The yellow bone marrow acts as a storage reserve of fatty acids.  Acid-base balance — Bone buffers the blood against excessive pH changes by absorbing or releasing alkaline salts.  Detoxification — Bone tissues can also store heavy metals and other foreign elements, removing them from the blood and reducing their effects on other tissues. These can later be gradually

released for excretion.

 Endocrine organ - Bone controls phosphate metabolism by releasing fibroblast growth factor - 23 (FGF-23), which acts on kidneys to reduce phosphate re absorption. iCBSE.com

Characteristics 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. iCBSE.com

Cellular structure There are several types of cells constituting the bone;  Osteoblasts are mononucleate bone-forming cells that descend from osteoprogenitor cells. They are located on the surface of osteoid seams and make a protein mixture known as osteoid, which mineralizes to become bone. The osteiod seam is a narrow region of newly formed organic matrix, not yet mineralized, located on the surface of a bone. Osteoid is primarily composed of Type I collagen. Osteoblasts also manufacture hormones, such as prostaglandins, to act on the bone itself. They robustly produce alkaline phosphatase, anenzyme that has a role in the mineralisation of bone, as well as many matrix proteins. Osteoblasts are the immature bone cells.  Bone lining cells are essentially inactive osteoblasts. They cover all of the available bone surface and function as a barrier for certain ions.  Osteocytes originate from osteoblasts that have migrated into and become trapped and surrounded by bone matrix that they themselves produce. The spaces they occupy are known as lacunae. Osteocytes have many processes that reach out to meet osteoblasts and other osteocytes probably for the purposes of communication. Their functions include to varying degrees: formation of bone, matrix maintenance and calcium homeostasis. They have also been shown to act as mechano-sensory receptors — regulating the bone's response to stress and mechanical load. They are mature bone cells.  Osteoclasts are the cells responsible for bone resorption (remodeling of bone to reduce its volume). Osteoclasts are large, multinucleated cells located on bone surfaces in what are called Howship's lacunae or resorption pits. 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. Osteoclasts mature and/or migrate to discrete bone surfaces. Upon arrival, active enzymes, such as tartrate resistant acid phosphatase, are secreted against the mineral substrate. iCBSE.com

Molecular structure Matrix 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.

Inorganic

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.

Organic

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 iCBSE.com

Types There are five types of bones in the human body: long, short, flat, irregular and sesamoid.  Long bones are characterized by a shaft, the diaphysis, that is much greater in length than width. They are comprised mostly of compact bone and lesser amounts of marrow, which is located within the medullary cavity, and spongy bone. Most bones of the limbs, including those of the fingers and toes, are long bones. The exceptions are those of the wrist, ankleand kneecap.  Short bones are roughly cube-shaped, and have only a thin layer of compact bone surrounding a spongy interior. The bones of the wrist and ankle are short bones, as are thesesamoid bones.  Flat bones are thin and generally curved, with two parallel layers of compact bones sandwiching a layer of spongy bone. Most of the bones of the skull are flat bones, as is thesternum.  Irregular bones do not fit into the above categories. They consist of thin layers of compact bone surrounding a spongy interior. As implied by the name, their shapes are irregular and complicated. The bones of the spine and hips are irregular bones.  Sesamoid bones are bones embedded in tendons. Since they act to hold the tendon further away from the joint, the angle of the tendon is increased and thus the leverage of the muscle is increased. Examples of sesamoid bones are the patella and the pisiform.Compared to woven bone , lamellar bone formation takes place more slowly. The orderly deposition of collagen fibers restricts the formation of osteoid to about 1 to 2 μm per day. Lamellar bone requires a relatively flat surface to lay the collagen fibers in parallel or concentric layers. iCBSE.com

Formation The formation of bone during the fetal stage of development occurs by two processes: Intramembranous ossification and endochondral ossification. Intramembranous 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:

1. Development of ossification center
2. Calcification
3. Formation of trabeculae
4. Development of periosteum Endochondral ossification 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: iCBSE.com

Remodeling 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. Purpose 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.

Calcium balance

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.

Repair

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.[4] iCBSE.com

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. Osteoblast stimulation 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.[5]^ 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. Osteoclast inhibition 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. iCBSE.com

Report of Project

EXPERIMENT OBSERVATION

 A strip of bone was burnt in evaporating dish Yellowish white precipitate was obtained  2 gms of bone as was weighed  To it dilute nitric acid was added On adding Nitric acid the ash sparingly dissolved  It was diluted with water and the ash was completely dissolved  The above solution was filtered and the residue (left on the filter paper) was discarded  Ammonium hydroxide was added to the filtrate (left on the beaker) The pH was made to 8. Whitish brown precipitate of Magnesium ammonium phosphate was obtained  The solution was made basic. The basicity was checked with the help of pH paper  The solution was filtered and the residue was isolated  The filtrate was separated into two test tubes White precipitate of Silver chloride was obtained  Silver nitrate was added to one of the test tubes White residue of calcium  To the other test tube ammonium chloride and ammonium carbonate was added simultaneously and boiled Carbonate was obtained  To the solution left, dilute HCL was added followed by Potassium thiocyanate Red colour solution marking the presence of Iron was obtained iCBSE.com

Result

Extrapolation from the above observations

Constituents of bone ash identified were:

I. Calcium

II. Phosphate

III. Chloride

IV. Magnesium

V. Iron

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

 Weight of Calcium carbonate:- 1 .7 g

 Weight of Mg (NH 4 ) PO 4 :- 1.1 g

 Weight of Ca in 2g of sample:- 0.68 g

 Weight of Phosphorous:- 0.24 g

 % of Ca:- 34%

 % of Phosphorous:- 12%

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