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34 Cards in this Set
- Front
- Back
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What 4 elements make up the skeletal system? |
1. Bones 2. Cartilages 3. Ligaments 4. Articulations (joints) 1+2 = skeleton |
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Classification of connective tissue |
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Connective tissue |
Cells + Extracellular matrix (fibres and ground substance) = CT |
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Function of bone |
1. Support 2. Protection 3. Assistance in movement 4. Mineral homeostasis |
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How does bone provide support? |
Rigid framework for tissues |
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What protection does bone provide? |
• Protects soft tissues e.g. brain, spinal cord, vertebral column, heart
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How does bone assist in movement? |
• Facilitates movement of the body
• Surface for attachments of muscles • Resistance to the force of gravity |
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What does mineral homeostasis involve? |
Storage of minerals and lipids |
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What is periosteum? |
It is found on the outside of bone. This is a dense fibrouslayer, where muscles insert. It contains bone forming cells. It is notfound in the regions of bone covered by articular cartilage.
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What is endosteum? |
The name given to the tissue that lines the innersurfaces of bones
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Structure of bone |
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Characteristics of bone |
• Bone is resistant to bending, twisting, compression and stretch.
• It is hard, because it is calcified, and the collagen fibres help the boneto resist tensile stresses.
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If you dissolve away the calcium salts of bone, then....
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the bone becomes rubbery because of the collagen fibres which are left behind.
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What is extracellular matrix made of? |
It is made up of an organic matrix (30%) containing proteoglycans(but less than cartilage), glycosaminoglycans, glycoproteins,osteonectin and osteocalcin.
There are collagen fibres (mostly type I (90%), with some type V).Only 25% of bone is water. Almost 70% of bone is made up of bonemineral called hydroxyapatite. |
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What does osteonectin do? |
Anchors bone mineral to collagen
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What does osteocalcin do? |
Calcium binding protein
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Before the extracellular matrix is calcified, the tissue is called...
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Osteoid (bone-like) tissue
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The bone calcifies when...
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The concentrations of calcium and phosphate ions rise high enough so are deposited into the extracellular matrix. Calcification occurs only in presence of collagen fibres - salts crystallize in the spaces between the fibres, then accumulate around them. |
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Impaired calcification leads to... |
Higher levels of osteoid tissue than normal |
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Cells of the bone |
• osteoblasts (osteo - bone)
• osteocytes • osteoprogenitor cells • osteoclasts |
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Osteocytes |
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Osteoclasts |
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Osteoprogenitor cells and osteoblasts cells |
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Types of bones |
1. Woven (or primary) bone - first bone formed at any site, collagen fibers are random. It is soon replaced by lamellar. 2. Lamellar bone - the collagen fibres have become re-modelled to become more parallel in layers. |
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Types of mature bone |
1. Compact bone - found in the shafts of long bones (in diaphyses). This makes up 80% of all bone. 2. Spongy bone - found in the ends of long bones (in the epiphysis). This makes up 20% of all bone. This type of bone contains red bone marrow and a network of bony trabeculae. |
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Compact |
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Cancellous bone |
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Classification of joints
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Cells of cartilage |
Chondroblasts and chondrocytes, (chondro - cartilage) andextracellular matrix, made up about 10% aggrecan, 75% water, and amix of collagen fibres and other constituents.
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What is cartilage? |
Cartilage is a strong, flexible and semi-rigid supporting tissue. It canwithstand compression forces, and yet it can bend.
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Importance of extracellular matrix |
- The extracellular matrix soaks up water, like a sponge, (osmotic effect)due to the properties of the GAG: aggrecan, producing the high watercontent (75%). • The collagen fibres form a network which has a very high tensilestrength, and which entraps the aggrecan molecules.
• When you stand up or walk, the weight of your body is supported bythe cartilagenous ends of the long bones. In this state your weightcompresses the cartilage, literally squeezing the water out, until theforce produced by the osmotic swelling is equal to the compressiveforce generated by your weight. |
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Types of cartilage |
1. Hyaline 2. Fibrocartilage 3. Elastic cartilage |
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Articular cartilage |
Hyaline cartilage |
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3 types of cartilage |
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