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7 Cards in this Set
- Front
- Back
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5 Functions of the Skeleton |
-Support (long bone frame and vertebral column, plus viscera support) -Protection, for brain, spinal cord, viscera, lungs and heart -Movement, provides leverage -Blood formation (red bone marrow produces RBCs) -Storage of calcium, phosphorous and other nutrients |
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4 Bone cell types |
Osteogenic - stem cell precursor to osteoblasts Osteoblasts - synthesize bone matter Osteocytes - former osteoblasts trapped in the bone matrix they've created, inhabiting lacunae, connected by canaliculi Osteoclasts - bone dissolving cells, arise from bone marrow stem cells. Dissolve unneeded/damaged bone, or scavenge normal bone for minerals in a process called resorption |
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Intramembraneous ossification |
Flat bone produced within mesenchymal membrane. Mesenchymal cells secrete collagenous osteoid tissue, calcium phosphate crystallizes these tissues fibers into trabeculae of spongy bone. At surface, osteoblasts fill in spaces between trabeculae, creating layer of compact bone encasing spongy. |
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Calcium homeostasis |
Regulated by two hormones: -calcitriol, the most active form of vitamin D, stimulates calcium absorption from food, raising blood levels -Parathyroid hormone PHT, secreted by parathyroid glands in response to low blood calcium levels, stimulates bone resorption, kidney reabsorption of calcium, and calcitriol synthesis. |
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Endochondral ossification |
Hyaline cartilage outline of future bone is created, interior chondrocytes inflate, die, become calcified. Outside lining hardens into supportive bone. Blood vessels, osteoclasts in interior dissolve calcified tissue to create primary marrow cavity. Osteoblasts arrive and begin to thicken bone lining the cavity. |
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Metaphysis |
Area at ends of long bone where cartilage is replaced by bone tissue, results in growth. |
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Epiphyseal plate |
Separates primary and secondary marrow cavities, it's a layer of hyaline cartilage with a metaphysis on either side. |
