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23 Cards in this Set
- Front
- Back
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What are the 5 functions of bone?
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1. protection
2. mineral storage 3. movement 4. support and shape 5. hematopoiesis |
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Of the composition of bone, what % of its mass is composed of cells?
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5-8% of its mass are cells, th remaining 92-95% is extracellular matrix.
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Of the extracellular matrix, what percent is made up of Organic matter?
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35% is organic matter (osteoid)
90-95% of the organic matter is Type I collagen |
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Of the extracellular matrix, what percent is made up of Inorganic Matrix?
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65% is inorganic matrix
70% of the inorganic matter is Hydroxyapatite |
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What are the four macroscopic components of a bone?
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1. Cortical bone
2. trabecular bone 3. periosteum 4. endosteum |
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What are the characteristics of cortical bone?
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- Lemellar collagen fibers
- dense and strong - outer covering supports and protects bone |
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What are the characteristics of trabecular bone?
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- lamellar and woven
- found in bone medullary cavity, skull, vertebral bodies |
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What are the characteristics/functions of periosteum?
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- The outer fibrous and vascular layer of bone
- Inner cambium layer contains osteoblasts and osteoclasts - functions in growth, repair and nutrition of bone |
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Where is the endosteum?
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It lines the inner margin of the cortex and trabeculae.
- It also contains osteoblasts and osteoclasts |
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What are the four divisions of bone?
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1. Epiphysis
2. Physis 3. Metaphysis 4. Diaphysis |
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What are the four types of cells in bone?
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1. Osteoprogenitor cells (becomes fibroblasts, chondroblasts, or osteoblasts)
2. Osteoblasts 3. Osteocytes 4. Osteoclasts |
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What enzyme is contained in the cytoplasm of osteoblasts?
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Alkaline Phosphatase
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If a Dr. wanted to determine if there was a broken bone, what would be the purpose of doing a blood test?
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The Dr. would be checking for alkaline phosphatase in the blood, as it is an indicator of osteoblastic activity and possible broken bone or tumor in the bone.
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Which cell within bone mediates Wolff's Law?
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Osteocytes
They regulate the cell environment |
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Within bone, where are osteocytes located?
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Within the canniliculi. They transport fluid through the canniliculi.
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Which cells within bone are multinucleated?
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Osteoclasts
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Where do osteoclasts reside within bone?
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Howship's lacunae
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Hyperemia in bone leads to what?
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Increased osteoclastic activity, resulting in osteoporosis
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Ischemia in bone leads to what?
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Increased osteoblastic activity, resulting in bone sclerosis
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When does ossification begin (what weeks?) in the fetus?
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6th, 7th, and 8th weeks
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Describe intramembranous bone formation
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bones form directly from osteoblasts that are clustered within a fibrous membrane. There is no pre-existing cartilage model.
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Where does intramembranous bone formation predominate during fetal growth development?
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In the skull and facial bones, as flexibility is needed.
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Describe endochondral bone formation
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A pre-existing cartilage model calcifies and is replaced by bone.
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