Presentation on theme: "Dysfunction of the Skeletal System"— Presentation transcript:
1 Dysfunction of the Skeletal System Homeostatic Imbalances and Bone Repair
2 Homeostatic Imbalances of Bone OsteoporosisArthritisOsteomalacia/RicketsPaget’s Disease
3 Homeostatic Imbalances of Bone (Osteoporosis) Normal matrix, but decreased bone massBone reabsorption > Bone depositOsteoclast more active than osteoblastsPorous, light, fragile bonesSpongy bone most vulnerableEx. Compression fractures of vertebrae, neck of femur
4 Homeostatic Imbalances of Bone (Osteoporosis) Bone health maintained by hormonesEstrogen: restrain osteoclasts and promote bone depositionGreatest Risk Factors:Older, post-menopausal womenPetite bodyInsufficient load-bearing exerciseDiet poor in Calcium, Vit D and proteinThyroid diseaseDiabetesSmoking (reduces estrogen, promotes weight loss)
5 Homeostatic Imbalances of Bone (Osteoporosis) Prevention: focuses on reversing risk factorsdietary supplementsLoad bearing exercise* hormone (estrogen) replacement therapy (HRT)Alternative Therapies:Alendronate: drug reduces osteoclast activitySelective Estrogen Receptor Modulators (SERMS): mimic estrogen’s benefits without risks associated w/ HRTStatins: cholesterol medication that increases bone density as side effect.Soy protein: supplements diet, contain estrogen-like compounds* Associated risk of heart attack, stroke, breast and uterine cancer
6 Homeostatic Imbalances of Bone (Osteoporosis) Bone Density TestSpecial X-rays used to measure mineral content of bone.Repeated every 2–3 yearsBone Density Scan of a NORMAL menopausal womanColor Ranges: Blue/purple, least dense to white, most dense
7 Homeostatic Imbalances of Bone (Arthritis) > 100 typesinflammation of joint, causing painOften cartilage is broken downRheumatoid arthritisautoimmunebody’s own cells of IS attack soft tissue around joint.
8 Homeostatic Imbalances of Bone (Osteomalacia/Rickets) “Soft bones”:bones w/ matrix and structure, but minimal calciumInsufficient Ca and Vit D dietOsteomalacia: adult formReversible with dietary changes.Rickets: youth formmore severe: bones still developingcauses bowed legs and deformed pelvis, skull, ribsAbnormally long bones due to lack of calcification of epiphyseal plateBone deformities permanent.
9 Homeostatic Imbalances of Bone (Paget’s Disease) Disorganized resorption and formation of boneHigh spongy bone: compact bone ratioReduced mineralizationOsteoclast activity < Osteoblast activity causing bone thickeningFractured right femur of Paget’s patient due to weakening of bones
10 Classification of Fractures I. Position Non-displaced: bone ends in alignmentDisplaced: bone ends out of alignment
11 Classification of Fractures II. Breakage Complete: Fractures break all the way throughIncomplete: partial fracture
12 Classification of Fractures III. Orientation Linear: fracture runs parallel along the axisTransverse: fracture is perpendicular to the axisLinear Transverse
13 Classification of Fractures IV. Skin Penetration Simple:Fracture does not pierce skinCompound:Fracture pierces skin
14 Classification of Fractures Appearance Comminuted: Bone fragments into multiple piecesCompression: crushed bone
15 Classification of Fractures Appearance Spiral: ragged break due to twisting forcesDepressed: Bone portion pushed inwards
16 Classification of Fractures Appearance Greenstick: incomplete fracture; Only one side of the shaft breaks; the other side bends.
17 Classification of Fractures Position Epiphyseal: separation of epiphysis from diaphysis along epiphyseal plate
18 Treating Fractures Reduction: realignment of broken bone ends Closed/External: hands used to coax bones back to realignmentOpen/Internal: surgical realignment of bone ends secured together by pins or wiresImmobilization with cast or traction
19 Bone Repair Osteoblasts convert cartilage to spongy bone Blood clots Bone cell deathinflammationCapillary growthPhagocytes eat cell debrisFibroblasts bridges gap with collagen FIBERChondroblasts secrete CARTILAGE matrix to create framework for bone formation. Cartilage later calcifies and dies.
20 Bone Lengthening Surgery Lengthens bone up to 3 inProcedure:Breaking bones of leg (tibia/fibula or femur)Bone moved apart 1 mm/day w/ external deviceBody regenerates newbone to fill-in space asmatrix tearsRepair deformitiesCosmetic Reasons(Extreme make-over)
21 Bound Feet in ChinaSmall “lotus” feet (< 4 in.) = symbol of beauty in China up until 1920’sYoung girls’ feet broken and bent so toes bound under foot