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85 Cards in this Set
- Front
- Back
Functions of the Skeletal System |
1) Support 2) Protection 3) Mineral Storage 4) Triglyceride storage (yellow marrow) 5) red/white blood cell formation 6) leverage (assistance in movement) |
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2 Divisions of the Skeletal System |
Axial: skull, spine, thoracic cage Appendicular: legs and arms |
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Anatomy of a long bone |
Epiphysis Metaphysis Diaphysis Edosteum: inner surface lining of bone marrow cavity, traveculae of spongey bone, canals of compact bone. Contains osteogenic cells. Periosteum: Connective membrane tissue covering external, attached to bone matrix via perforating fibers, 1) outer fibrous, 2) inner osteogenic
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Osteogenic Cells |
stem cells formed from mesenchyme. Mitosis > daughter cells Differentiation > osteoblasts
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Osteoblasts |
build bone, synthesize organic components, initiate calcification (taking calcium from blood and deposit into matrix) |
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Osteocytes |
Mature cells involved in maintenance of bone. Senses micro damage and mechanical forces on bone then sends signals for repair. Housed in lacuna. |
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Osteoclast |
Breaks down bone, release proteolytic enzymes and acids to degrade collagen and release minerals into blood. Derived from myeloid cells. |
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Organic Components of Bone Matrix |
Osteoblasts secretion Ground substance: glycoproteins-GAG Type 1 Collagen: fibrous protein arranges in helical form. Resistant to pulling forces, provides flexibility and framework |
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Inorganic Components of Bone Matrix |
25% water (attracted to ground substance) Hydroxyapatite (calcium minerals and ions) Forms mineral plates that fill spaces within collagen fibers, provides firmness. |
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Component Hierarchy |
Osteoblasts > Tropocollagen (triple helix) > microfibril > fibril > fiber > lamella > osteon/tribecullae > compact bone/spongey bone > bone |
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Bone Modeling |
Bones form through osteoblasts without prior bone resorption. Occurs during growth, produces change in bone size/shape |
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Bone Remodeling |
Bone is resorbed by osteoclasts and then new Bone is built. Maintenance of bone strength. |
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Spongey Bone |
Irregular lattice of trabeculae Epiphysis of Long bones, surrounding marrow cavities Flat, short, irregular bones Withstand forces in many directions (trabeculae arrangement), lightens skeleton, red marrow for hemopoesis More metabolically active than compact |
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Compact Bone |
Network of Bone organized into concentric rings (osteons), alternating twisting of collagen between layers External layer of all bones, diaphysis of Long bones Gives Long bones ability to withstand forces along longitudinal axis |
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Long bone |
More length than width Humerus, femur |
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Short bone |
Square/trapezoidal Carpals |
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Flat bone |
Sternum, ribs |
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Irregular Bones |
Vertebrae |
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Sesamoid bones |
Seed shaped in mostly in soft tissue Patella |
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Activation |
Preosteoclasts are stimulated and differentiate under the influence of cytokines and growth factors into mature osteoclasts |
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Resorption |
Osteoclasts digest mineral Matrix (old bone) |
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Reversal |
End of resorption; recruitment of osteoblasts |
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Formation |
Osteoblasts synthesize new bone matrix |
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Quiescence |
Osteoblasts become resting bone lining cells on new surface |
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Intramembranous Ossification |
Mesenchyme to Bone Cranial bones, mandible, sternum, and clavicle Heterotropic bone formation |
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Endochondral Step 4 |
Osteoblasts form bone on the outer surface of the model |
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Endochondral Step 5 |
Osteoblasts create primary Ossification center Bone replaced Cartilage |
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Endochondral Step 6 |
Osteoclasts create marrow cavity |
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Endochondral Step 7 |
Spongey bone remodeled to compact bone |
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Endochondral Step 8 |
Around birth, a secondary Ossification center forms |
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Endochondral Step 9 |
Spongey bone replaces Cartilage at the epiphysis with the exception of epiphyseal plates and articulate Cartilage |
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Ossification |
Replacement of connective tissue with bone |
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Calcification |
Deposition of calcium |
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Primary Ossification |
Marrow cavity formed, replaces Cartilage with bone, located in the diaphysis, occurs before birth |
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Secondary Ossification |
No marrow cavity, Cartilage is left for epiphyseal plates and articular cartilage, located in epiphysis, occurs around time of birth |
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Heterotropic bone formation |
Occurs where bone doesn’t naturally occur (sesamoid bones) |
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Interstitial Growth |
Occurs within the cartilage of the epiphyseal plate and increases length |
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Steps of Interstitial Growth |
1) Chondrocytes build matrix and differentiate into cytes 2) chondrocytes divide 3) chondrocytes build matrix and spread apart 4) Cartilage grows from within |
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Growth at the Epiphyseal Plate |
Diaphyseal osteoclasts break down cartilage Osteoclasts lay down spongey bone Chondrocytes continue to form cartilage Growth in length stops when the osteoclasts/blasts work faster than the chondrocytes in the proliferating zone Epiphyseal plate closes |
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Appositional Growth |
Growth at the outer surface, increase in width |
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Appositional Growth Steps |
1) periosteal osteogenic cells differentiate into blasts (ridges in periosteum create groove for vessel) 2) blasts build bone on outer surface of diameter of marrow cavity (ridges fuse, endosteum lined tunnel) 3) bone diameter, cortical width, and medullary cavity increases (osteoblasts in endosteum build new concentric lamellae) |
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Intramembranous Step 1 |
Development of ossification center. Mesenchyme cells differentiate into osteogenic cells, then into osteoblasts, osteoblasts secrete Bone Matrix. |
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Intramembranous Step 2 |
Calcification Osteoblasts deposit calcium into the matrix and differentiate into osteocytes |
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Intramembranous Step 3 |
Formation of trabeculae (spongey bone) |
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Intramembranous Step 4 |
Development of periosteum Remodeling of spongey bone into compact bone |
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Endochondral Ossification |
Mesenchyme to Cartilage to bone Most bones in the body Primary and secondary Ossification |
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Endochondral Step 1 |
Cartilage model forms Mesenchyme cells into chondroblasts |
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Endochondral Step 2 |
Growth of Cartilage model Interstitial = length Appositional = width |
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Endochondral Step 3 |
Blood vessels penetrate model and stimulate differentiation of osteogenic cells into osteoblasts |
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Traumatic Fracture |
Normal bone with abnormal fractures |
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Bone Repair Steps |
1: nearby bone cells die which leads to swelling and inflammation, phagocytes/osteoclasts remove damaged tissue 2: blood vessels grow into hematoma, mesenchyme differentiates, growth of Cartilage and collagen, to produce spongey bone 3. Bone remodeling |
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Open Reduction |
Surgical rods |
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Closed Reduction |
Natural healing with splinting and setting |
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Dietary Factors of Calcium Homeostasis |
Minerals: Calcium and phosphorous Vitamins: A(stimulated osteoblast activity), C (needed for collagen synthesis), D (stimulates calcium absorption), K B12 (synthesis of proteins) |
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Calcitonin |
Stimulus: high blood calcium Source: thyroid gland Target Tissue: bone, kidney, intestine Actions: inhibits osteoclast activity, increase excretion of calcium at kidney, inhibits absorption at intestine |
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Parathyroid Hormone |
Stimulus: low blood calcium Source: parathyroid Target tissue: bone, kidney, intestine Actions: stimulates osteoclast activity, decreases excretion of calcium at kidney, stimulate intestinal absorption of calcium |
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Calcitrol |
Active form of vitamin D. Stimulates osteoclast activity, decreases calcium excretion at kidney, increase absorption at intestine Steroid hormone derived from cholesterol
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Calcium Intake |
1000 mg |
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Growth Hormone (somatotropin) |
Stimulates cell growth and protein synthesis Stimulates the formation of insulin which stimulates osteoblast activity which stimulates bone formation |
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Pituitary Dwarfism |
Children with low levels of growth hormone meanings slow epiphyseal growth and short stature |
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Pathologic Fracture |
Abnormal bone with normal fractures |
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Pituitary Giganitism |
Hyper-secretion of growth hormone in childhood leading to accelerated epiphyseal growth and tall stature |
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Acromegaly |
Hypersecretion of growth hormone after puberty meaning appositional growth in skulls, hands and feet. |
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Estrogen/Testosterone |
Stimulate osteoblast activity Increased levels at puberty means growth spurts until epiphyseal plate closes |
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Incomplete Fracture |
Bone is partially broken |
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Complete Fracture |
Loss of continuity |
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Greenstick Fracture |
Incomplete: one side broken, the other bent |
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Non-Displaced Fracture |
Complete with no separation |
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Displaced Fracture |
Complete with separation |
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Simple (Closed) Fracture |
Piece of bone does not brake skin |
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Open (compound) Fracture |
Complete with skin break |
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Other Fractures |
Transverse Oblique Spiral Communicated Impounded |
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Effect of Exercise on the Bone |
1) muscles pulling on joint > joint reaction forces 2) impact > ground reaction forces |
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Elbow Joint |
Mono-Axial Trochlea - ulna Capitulum - radius |
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Hip Joint |
Tri-axial Special ligament inside acetabulum and femoral head |
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Knee Joint |
Mono-Axial Meniscus cushion Intracapsular and extracapsular ligaments |
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Mechanical Force on Bones |
Sensed by osteocytes > proliferation of osteoblasts (influx of calcium) > gap junctions > bone cell response bone formation greater than bone resorption |
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Osteoporosis |
Proportion of collagen and minerals is normal but a decrease in mass. Porous trabeculae. |
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Synarthrosis |
Immovable joint Situation bones, alveolar process with teeth, epiphyseal plates |
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Amphiarthrosis |
Slightly movable joint Between tibia/fibula, pubic symphysis |
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Diarthrosis (and synovial) |
Freely movable joint Covered in protective connective tissue Shoulder, elbow, hip |
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Arthritis |
1) osteoarthritis (oa) - degenerative (thinned articular Cartilage) 2) rheumatoid - inflammatory (swelling in synovial membrane) |
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Temporomandibular Joint |
Only movable joint of the skill Mandibulat chondyle and the mandibular fossa TJM- pulling mandible out of joint |
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Ribs and Vertebrae |
1- facets The rest have demi facets |
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Shoulder joint |
Try-Axial - more prone to injury Stabilized by coracohumeral ligament, glenohumeral ligament, transverse humoral ligament Upward rotation of scapula and lateral rotation of humerus |