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Chapter 2
Background
2.1 Introduction
Chapter 2 will describe the essential background information needed to understand this
thesis project. A description of the biology of bone will be provided first and its focus
will be limited to femurs and tibiae, since those are the structures we have used
throughout this project. As well, we will briefly describe the analysis techniques that are
currently used to evaluate bones. Furthermore the theory behind the used technique and
instrumentation will be addressed. Previous bone studies using transcutaneous in vivo
Raman spectroscopy will also be described, as well as the differences between them and
the present thesis project.
2.2 Bone Structure and Composition
Bones
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12 Both the cortical and
trabecular structures provide ions like calcium phosphate, phosphorous, sodium and
magnesium that are basic to maintain the homeostasis of the bone.
Figure 1. Hierarchical structure of bone. Cotical bone is made of osteons (10-500 µm). Osteons are composed of concentric lamella (3-7 µm) and a Haversian cannal. A lamella is composed of mineralized collagen fibers, which are made up of collagen fibrils (0.5 µm each). A fibril is made up of collagen molecules and apatite nano-crystals.11
The three major components of bone tissues are: type I collagen, water and dahllite
crystals. 13 Dahllites are plate-shaped carbonated apatite crystals, which have “small but
significant amounts of impurities such as HPO4, Na, Mg, citrate, carbonate, K”. 14,15 The
apatite crystal lattice is then responsible for the degree of mineralization in bone tissue.
Type I collagen is the primary matrix component and its molecules are secreted by
Cortical bone
Osteons
Haversian canal
Concentric lamella
Mineralized collagen fibrils
Collagen molecule
Apatite nanocrystals 6 osteoblasts, these molecules will then arrange into collagen fibrils and subsequently to
collagen fibers, which are the basis to lamellae.
Type I collagen despite being the primary protein is not the only one present in
bone tissue, which also contains non-collagenous proteins.
9. Hyaline cartilage is found on many joint surfaces, it has a very firm consistency. It contains no nerves or blood vessels, and its structure is relatively simple. Elastic cartilage, also called yellow cartilage, is present in the ears; it contains elastic fiber networks and collagen fibers. Fibrocartilage is found in the pubic symphysis, the annulus firbrosus of the intervertebral discs, menisci and the TMJ. During labor, the pubic symphysis is loosened to aid in delivery.
s Flat bones Irregular bone Sesamoid bones Anatomy of a Long Bone Epiphyses Metaphyses Epiphyseal growth plate Epiphyseal growth line Diaphysis Periosteum Medullary cavity Endosteum Articular cartilage Microscopic Anatomy Compact bone Osteons Spongy bone Trabeculae Bone Formation Intramembranous ossification Endochondral ossification Cells in Bone Osteogenic cells Osteoblasts Osteocytes Osteoclasts Hormonal Control of Bone Calcitonin Parathyroid hormone Osteology of the Axial Skeleton Frontal Parietal Temporal Zygomatic arch Mastoid process Occipital Foramen magnum Occipital condyles Sphenoid Sella turcica Greater wing Lesser wing Ethmoid Cribriform plate Crista galli Nasal Maxilla Alveolar process Palatine process Zygomatic Zygomatic arch Lacrimal Palatine Inferior nasal conchae
Most types of connective tissue contain fibrous strands of the protein collagen that add strength to connective tissue. Some examples of connective tissue include the inner layers of skin, tendons, ligaments, cartilage, areolar, adipose bone and fat tissue. In addition to these more recognizable forms of connective tissue, blood is also considered a form of connective tissue.
The slide below shows a section of the trachea (windpipe). Rings of hyaline cartilage embedded within the walls of the trachea provide support and help to maintain an open airway. Hyaline cartilage is the most common form of cartilage in the body, making up part of the nose, connecting ribs to the sternum, and covering the articulating surfaces of bones. When sectioned and stained, the matrix of hyaline cartilage takes on a light purple color. Cartilage-forming cells called chondroblasts produce this matrix, which consists of an amorphous ground substance heavily invested with collagen fibers. Chondrocytes (mature cartilage cells) can be seen singly or in groups within spaces (called lacunae) in
Materials for this laboratory included Microsoft excel to compile data, a pen and paper to record data, a 15cm ruler, string, a caliper, and a two meter ruler. Since bones often times vary in width in certain portions of the same bone due to the presence of joints and processes the bone was measured at the midpoint along its length for its true width. Measurements
In this content am going to be talking and explaining the structure and function of the skeletal system. I will be talking about: Axial skeleton, Appendicular. Also highlighting the different types of bone such as long bones, short bones flat bones, irregular bones and sesamoid bones. I am also going to be talking about how your body is
Generally, bone can be classified into two categories according to its structure, cortical (compact) and trabecular (cancellous or spongy) bone. Cortical bone is stiff, with 5–10% porosity, and it makes up approximately 80% of skeletal bone, including cuboidal bones, flat bones, and the ends of long bones. Cortical bone is much denser, stiffer, and stronger than trabecular bone. The average strength of a compact human bone was 105 MPa in a longitudinal compression test, and was 131 MPa in a transversal compression test. In the same experiment, the average longitudinal strength in tension was 53 MPa [39]. In contrast, the porosity of trabecular bone is approximately 50–95%, which is higher than that of cortical bones. The surface area of the
The skeletal system is made up of bones and joints. Bones are a dry dense tissue that is composed of calcium phosphorous and organic matter. The bones are protected and covered by a layer of fibrous connective tissue membrane called the periosteum (Brown, et al., 2015, p. 1547). There are two basic types of bone tissue: Compact Bone and Spongy Bone. Compact bones are dense smooth bones, while Spongy bones are composed of small needle-like pieces of bones and open space. Bones are then categorised according to the shape of the bone into four groups: long, short, flat and irregular. Long bones characteristically are typically longer then they are wide and generally have a shaft with heads at either ends e.g. the humerus. They are mainly compact bones. Short bones
Bone arrangement is a vital procedure in the improvement of the human body. It begins amid the improvement of the hatchling, and proceeds all through youth and immaturity as the skeleton develops. Bone redesigning in the mean time is a long lasting procedure, comprising of resorption (the separating of old bone) and hardening (arrangement of new bone), and is vital to molding the skeleton and to the repair of bone
In this exercise, we will examine a fresh raw chicken bone to study bone structure.
Osseous tissue contains specialized cells, cell products, and a fluid matrix. The distinctive solid, stony nature of bone results from the deposition of calcium salts within the matrix. Crystals of calcium phosphate account for almost two-thirds of the weight of the bone. The majority of
The skeletal system is made up of cartilage and bone. Both bone and cartilage are connective tissues, that is, they are composed of cells in a matrix with intracellular fibers. Just imagine connective tissue as a gelatin salad with grapes and coconut. The grapes would represent cells, the gelatin the support material for matrix, and the pieces of coconut the intracellular fibers. By changing the amounts of each ingredient and adding extra substances, we can produce a material that is very hard like bone and can withstand weight or softer like cartilage which can be used as a cushioning material. In this exercise, we will examine a fresh raw chicken bone to study bone
This paper summarizes the process and implications of bone remodeling as proposed by Svetalana V. Komarova, Robert J. Smith, S. Jeffrey Dixon, Stephan M Sims, and Lindi M. Wahl. Bone remodeling in the human body is an intricate process where osteoclasts resorb existing mineralized tissue and osteoblasts form new bone. Bone remodeling involves various interactions between different cells in the osteoclasts and osteoblasts. A problem occurs when these interactions are disturbed and can lead to numerous different bone disorders such as osteoporosis, osteoarthritis, or Paget’s disease. Manipulating Frost’s mechanostat theory, a theory that describes bone biology, and its corresponding biomechanical mathematical models of bone, Komoarova, Smith, Dixon, Sims, and Wahl were able to form their own model that allowed them to analyze how a change in interactions between cells can affect the bone remodeling process.
All proteins are composed of amino acids, organic molecules made from Carbon, Hydrogen, Oxygen and Nitrogen. Collagen is the most ample protein in mammals, in fact collagen constitutes around 25 % of a mammals entire protein content, Collagen is more precisely a family of proteins rather than one particular protein. Fibroblasts are the cells that usually produce collagen. Collagen is a complex molecules so doesn’t have a simple chemical structure for it; diagrams usually show collagen as a fiber.(Helmenstine 2015). There are 19 types of collagen in the collagen family, the 5 most abundant are type I collagen, found in connective tissue of skin, bones, teeth, tendons, ligaments, fascia and organ capsules, type II found in joint cartilage, type III, found in connective tissue of our organs such as liver, spleen and kidneys and type IV & V are the separating layer between epithelial and endothelial cells as well as between skeletal or smooth muscle cells , lens capsule, Schwann & glial cells of the nervous system.(Cellbone® technology 2007) Collagen is fibrous, fibrous proteins tend to have the hydrophilic R groups brought to the inside of the molecule and the hydrophobic R groups tend to be pushed to the outside of the molecule making it insoluble due to the hydrophobic and hydrophilic interactions . Collagen is also a strong structural protein thus Collagen suits its function in animal connective tissues such as bone skin and muscle. (Fullick et al 2015)