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19 Cards in this Set
- Front
- Back
Skeletal Tissue Forming Mesenchyme (STFM)
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Bone and cartilage develop from this type of mesenchyme; orginates in the trunk from SCLERATOME (tissues of somites paraxial mesoder) and SOMATIC MESODERM (lateral mesoderm)
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At the site of bone cartilage the STFM forms what?
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a Preskeletal Condensation of epithelial like cells expressing N-cadherin
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What Trascription factor forms cartilage
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Sox-9; The STFM turns into Chondroblasts that secrete Type II collagen
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What Transcription factor forms bone?
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Runx-2
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What determines what type of cartilage is formed?
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Matrix composition; Perichondrium will form around developing hyaline and elastic cartilage elements
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Osteoblasts secrete what?>
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Type I collagen
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Intramembranous ossification
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Bones that form directly from a preskeletal condensation that resembles a membrane of mesenchymal cells
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Endochondral Ossification
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Most bones; The cells in the STFM condensation from a cartilage model of the bone; the process usually begins in the middle of the cartilage model (long bones); the epuphysis will ossify at a later time (first t-factors are ihh, and Vegf)
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Ossification Centers
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are the areas of a bone primordia in which the ossification process begins (important for bone age)
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Secondary ossification centers
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Additional centers of bone formation appearing in the prenatal, the postnatal or the postpuberal period
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Primary ossification center
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the initial ossification center to form in a developing bone
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Chondrodystrophias
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Disorders characterized by disaproportionate growth
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Achondroplasia
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Autosomal dominant condition that affects 1/1000 live births; 80% of the cases appear spontaneously; Achondroplasia is the most common cause of short stature (dwarfism) ; shortened limbs, lordosis; Mutation in Fibroblast Growth Factor Receptor 3
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Marfan Syndrome
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Spider-like elongated digits and may also have aortic aneurysms, eye and spine abnormalities and joint hypermobility; Autosomal dominant; Defect production of FIBRILLIN a component of the ECM
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Mucopolysaccharidoses
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Family of metabolic diseases that affect bone formation resulting in dwarfism and bone irregularities; Autosomal recessive; accumulation of glycosaminoglycans in tissues and cells. chronic progressive distortions of the face and skull, thickened hairy skin, organ enlargement and altered mental development
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Osteogenesis Imperfecta
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(brittle bones); Defect in Type I collagen gene, dominant inheritance; multiple fracutures, BLUE SCLERA, ears jounts, spine and teeth; severe to mild
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Hyperpituiarism
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overproduction of growth hormone usually due to a tumor of pituitary gland tissue. Acromegaly (after plates have closed)
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Hypothyroidism
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Pituitary dwarf (cretinism); experience mental retardation as well as skeletal are ear anomalies; Their bone age is younger than it should be for their chronological age
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The first step of tissue development is
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Condensation of preskeletal mesenchyme
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