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Dysfunction of the Skeletal System

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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
Osteoporosis Arthritis Osteomalacia/Rickets Paget’s Disease

3 Homeostatic Imbalances of Bone (Osteoporosis)
Normal matrix, but decreased bone mass Bone reabsorption > Bone deposit Osteoclast more active than osteoblasts Porous, light, fragile bones Spongy bone most vulnerable Ex. Compression fractures of vertebrae, neck of femur

4 Homeostatic Imbalances of Bone (Osteoporosis)
Bone health maintained by hormones Estrogen: restrain osteoclasts and promote bone deposition Greatest Risk Factors: Older, post-menopausal women Petite body Insufficient load-bearing exercise Diet poor in Calcium, Vit D and protein Thyroid disease Diabetes Smoking (reduces estrogen, promotes weight loss)

5 Homeostatic Imbalances of Bone (Osteoporosis)
Prevention: focuses on reversing risk factors dietary supplements Load bearing exercise * hormone (estrogen) replacement therapy (HRT) Alternative Therapies: Alendronate: drug reduces osteoclast activity Selective Estrogen Receptor Modulators (SERMS): mimic estrogen’s benefits without risks associated w/ HRT Statins: 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 Test Special X-rays used to measure mineral content of bone. Repeated every 2–3 years Bone Density Scan of a NORMAL menopausal woman Color Ranges: Blue/purple, least dense to white, most dense

7 Homeostatic Imbalances of Bone (Arthritis)
> 100 types inflammation of joint, causing pain Often cartilage is broken down Rheumatoid arthritis autoimmune body’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 calcium Insufficient Ca and Vit D diet Osteomalacia: adult form Reversible with dietary changes. Rickets: youth form more severe: bones still developing causes bowed legs and deformed pelvis, skull, ribs Abnormally long bones due to lack of calcification of epiphyseal plate Bone deformities permanent.

9 Homeostatic Imbalances of Bone (Paget’s Disease)
Disorganized resorption and formation of bone High spongy bone: compact bone ratio Reduced mineralization Osteoclast activity < Osteoblast activity causing bone thickening Fractured right femur of Paget’s patient due to weakening of bones

10 Classification of Fractures I. Position
Non-displaced: bone ends in alignment Displaced: bone ends out of alignment

11 Classification of Fractures II. Breakage
Complete: Fractures break all the way through Incomplete: partial fracture

12 Classification of Fractures III. Orientation
Linear: fracture runs parallel along the axis Transverse: fracture is perpendicular to the axis Linear Transverse

13 Classification of Fractures IV. Skin Penetration
Simple: Fracture does not pierce skin Compound: Fracture pierces skin

14 Classification of Fractures Appearance
Comminuted: Bone fragments into multiple pieces Compression: crushed bone

15 Classification of Fractures Appearance
Spiral: ragged break due to twisting forces Depressed: 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 realignment Open/Internal: surgical realignment of bone ends secured together by pins or wires Immobilization with cast or traction

19 Bone Repair Osteoblasts convert cartilage to spongy bone Blood clots
Bone cell death inflammation Capillary growth Phagocytes eat cell debris Fibroblasts bridges gap with collagen FIBER Chondroblasts secrete CARTILAGE matrix to create framework for bone formation. Cartilage later calcifies and dies.

20 Bone Lengthening Surgery
Lengthens bone up to 3 in Procedure: Breaking bones of leg (tibia/fibula or femur) Bone moved apart 1 mm/day w/ external device Body regenerates new bone to fill-in space as matrix tears Repair deformities Cosmetic Reasons (Extreme make-over)

21 Bound Feet in China Small “lotus” feet (< 4 in.) = symbol of beauty in China up until 1920’s Young girls’ feet broken and bent so toes bound under foot



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