Term
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Definition
| Cells that are found in pockets called lacunae inside the cartilage |
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Definition
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Term
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Definition
| Dense irregular connective tissue that resists outward expression and contains blood vessels; surrounds cartilage |
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Definition
| Contains no blood vessels or nerves |
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Term
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Definition
| Cells in the perichondrium secrete matrix against the external face of exisiting cartilage |
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Term
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Definition
| Chondrocytes inside the cartilage divide and secrete new matrix, expanding the cartilage from within |
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Term
| Functions of the bones: Support |
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Definition
| Bones from the framework that support the body and cradle soft organs |
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Term
| Functions of the bones: Protection |
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Definition
| Bones provide a protective case for the brain, spinal cord, and vital organs |
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Term
| Functions of the bones: Movement |
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Definition
| Bones provide levers for muscles |
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Term
| Functions of the bones: Mineral and growth factor storage |
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Definition
| Bones are a resorvoir for minerals, especially calcium and phosphorus; growth factors such as insulin-like growth factors are also stored in the bone matrix |
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Term
| Functions of the bones: Blood cell formation |
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Definition
| Hematopiesis occurs within red marrow cavities of bones |
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Term
| Functions of the bones: Triglyceride (fat) storage |
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Definition
| Fat (yellow marrow) is stored in bone cavities |
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Term
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Definition
| Dense outer layer of bone, and shafts of long bones; regular arrangement of lamellae |
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Term
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Definition
| Honeycomb of trabeculae filled with red bone marrow |
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Term
| Periosteum (osteoblasts, osteoclasts) |
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Definition
- Double-layered protective membrane
- Outer fibrous layer in dense irregular connective tissue
- Inner osteogenic layer is composed mostly of osteoblasts and osteoclasts (also contains osteogenic cells which gave rise to osteoblasts)
- Richly supplied with nerve fibers, blood and lymphatic vessels
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Term
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Definition
- Delicate membrane covering all internal surfaces of the bone
- Also has osteoblasts and osteoclasts
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Term
| Chemical compisition of the bone |
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Definition
Organic (cells, osteoid)
Inorganic (hydroxyapatites) |
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Term
| Organic Components: Osteocytes |
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Definition
| Mature bone cells in bone tissue |
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Term
| Organic Components: Osteoblasts |
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Definition
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Term
| Organic Components: Osteoclast |
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Definition
| Large cells that resorb or break down bone matrix |
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Term
| Organic Components: Osteoid |
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Definition
| Unmineralized bone matrix composed of proteoglycans, glycoproteins, and collagen |
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Term
| Inorganic Components: Hydroxyapatites |
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Definition
- 65% of bone by mass
- Mainly calcium phosphate
- Responsible for bone hardness and its resistance to compression
- Serve as a mineral reservoir
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Term
| Osteogenesis and Ossification |
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Definition
| The process of the bone tissue formation, which leads to the following: the formation of the bony skeleton in embryos |
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Term
| Intramembranous Ossification |
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Definition
- Bone develops from a fibrous membrane formed by mesenchymal cells
- Begins at week 8 of embryo development
- Forms the cranial bones of the skull and clavicles
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Term
| Endochondral Ossification |
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Definition
- Bone forms by replacing hyaline cartilage
- Begins in the second month of development
- Uses hyaline cartilage "bones" as models for bone construction
- Forms long bones and other bones of the skeleton
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Term
| Stages of Endochondral Ossification |
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Definition
- Formation of bone collar around the primary ossification center in the diaphysis
- Caviation of the hyaline cartilage
- Invasion of internal cavities by the periosteal bud and spongy bone formation
- Formation of the medullary cavity; appearance of secondary ossification centers in the epiphyses
- Ossification of the epiphyses with hyaline cartilage remaining only in the epiphyseal plates
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Term
| Stages of Intramembranous Ossification |
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Definition
- An ossification center appears in the fibrous connective tissue membrane; mesenchymal cells cluster together and form osteoblasts
- Bone matrix (osteoid) is secreted within the fibrous membranes; osteoblasts secrete osteoid which is mineralized water; trapped osteoblasts become osteocytes
- Woven bone and periosteum form; osteoid is laid down between blood vessels forming a random network of trabeculae; mesenchyme on the external surface forms the periosteum
- Bone collar of compact bone forms, and red marrow appears: trabeculae deep to the periosteum thicken and later are replaced by compact bone; spongy bone remains in the center and its vessels become red marrow
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Term
| Postnatal Bone Growth: Growth in length of lone bones (epiphyseal plates) |
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Definition
- Epiphyseal plate cartilage closest to the epiphysis is relatively inactive
- Cells closer to the diaphysis organize into a pattern that allows for fast, efficient growth
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Term
| Postnatal Bone Growth: Four Functionally Different Zones |
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Definition
- Prolifercation (growth): cartilage cells divide, pushing the epiphysis away from the diaphysis
- Hypertrophic: older cartilage cells enlarge
- Calcification: matrix becomes calcified, cartilage cells die; matrix begins deteriorating
- Ossification (osteogenic): new bone formation occurs as osteoblasts secrete bone matrix onto calcified cartilage spicules
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