Bones Flashcards

1
Q

What is the matrix of bone called? And what is it made of?

A

Osteoid

Glycoproteins and collagen fibers

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2
Q

What is the main component of mineralization ?

A

Calcium hydroapatite (CHAP) crystals

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3
Q

What are the cellular elements of bone?

A

Osteoblasts
Osteocytes
Lining cells (inactive osteoblasts)
Osteoclasts

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4
Q

What are the two types of bone?

A

Wooooven bone - immature and randomly arranged

Lamellar bone- mature with collagen fibers arragned in a parallel pattern

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5
Q

What are the two ways of bone formation?

A

Intramembranous ossification - within “membranes” of condensed primitive mesenchymal tissue-> flat bones of the skull

Endochondral ossification -develops from hyaline cartilage that is replaced by osseous tissue present in the ossification centers

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6
Q

Where does endocondrial ossification occur?

A

Epiphyseal plate of developing bone

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7
Q

What is the condition of decreased length of long bones?

A

Chondrodysplasia

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8
Q

How does chondrodysplasia occur?

A

Membranous appositional growing is normal but interstitial growth of cartilage is abnormal resulting in premature closure of growth plate.

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9
Q

What are the most common cattle breeds that get chondrodysplasia?

A

Dexter cattle

Also angus and Hereford

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10
Q

What lethal form of chondrodysplasia is seen in dexter cattle?

A

“Dexter bulldog”

Inherited condition - affected cattle are often aborted and exhibit disproportionate dwarfism

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11
Q

Moo cow with …
shortened vertebral column, marked micromelia, large head with short muzzle, protruding tongue, and large abdominal hernia.

What is this?

A

Dexter bulldog

Chondrodysplasia

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12
Q

What is Wobblers syndrome?

A

AKA cervical-vertebral stenosis myelopathy

Localized skeletal dysplasia -> degenerative joint disease of the axial skeleton -> compression of spinal cord -> ataxia

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13
Q

What are the two types of cervical-vertebral stenosis myelopathy

A

Static - constant compression no matte the position of the neck

Dynamic - occurs when the neck is flexed

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14
Q

What is an inherited disease caused by osteoclast failure to reabsorb the primary spongiosia?

A

Osteopetrosis

AKA metaphyseal dysplasia

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15
Q

What is the pathogenesis of osteppetrosis ?

A

Decreased osteoclasts-> increase bone density and lack of medullary spaces –> aplastic anemia and bones susceptible to fracture (loss of flexibility)

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16
Q

Pig
Limbs (mostly forelimb) appear to be swollen due to excessive disposition of radiating trabecule on the periostal surface

What is this?

A

Congenital cortical hyperososis of pig

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17
Q

Amelia is ???

A

Absence of limb

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18
Q

Hemimelia is????

A

Absence of distal half of limb

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19
Q

Polymelia is ???

A

Supranumerary limbs

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20
Q

Micromelia is?

A

Abnormally small or short limbs

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21
Q

Syndactylia is??

A

Fusion of the digits

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22
Q

Polydactylia is ??

A

Supernumerary digits

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23
Q

___________ is a ventral deviation of the vertebral column

A

Lordosis

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24
Q

__________ is a dorsal deviation of the vertebral column

A

Kyphosis

25
Q

____________ is a lateral deviation of the vertebral column

A

Scoliosis

26
Q

____________ is a dorsal-lateral deviation of the vertebral column

A

Kyphoscoliosis

27
Q

___________ is due to asymmetric lesion of the growth plate, occurring in young animals

A

Angular limb deformities

28
Q

Lateral deviation of the joint is called _________ and medial deviation is called ___________

A
Valgus deformity (knocked kneed) 
Varus deformity (bow legged)
29
Q

Angular deformities can be caused by ???

A
Malposition in utero 
Joint laxity 
Hypothyroidism (congenital goiter) 
Trauma
Malnutrition 
Impaired endochondrial ossification
30
Q

Metabolic bone diseases are also called ________

A

Osteodystrophies

31
Q

Metabolic bone diseases are a result of disturbed bone growth or remodeling due to __________ or __________ imbalances

A

Nutritional; hormonal

32
Q

What nutritional imbalances can result in metabolic bone disease

A

Vitamin C, D, Ca, P, or protein

33
Q

What hormonal imbalances can lead to metabolic bone disease?

A

Parathyroid (PTH), thyroid (calcitonin), gonad (estrogen), and adrenal (corticosteroids) problems

34
Q

What toxicities can lead to metabolic bone diseases?

A

Learn and fluoride poisoning, hypervitaminosis A

35
Q

Metabolic bone disease are classified into what 4 conditions?

A

Osteoporosis
Rickets
Osteomalacia
Fibrous osteodystrophy

36
Q

What is osteoporosis ?

A

Osteopenia (decreased amount of bone) - reduced thickness of cortical bone and decreased number of trabeculae in the cancellous bone

37
Q

What are etiologies of osteoporosis ?

A

Nutritional - starvation, Cu deficiency, Vit C deficiency

Aging

Disuse

38
Q

What is rickets?

A

Metabolic bone disease of young growing animals

-defective calcification of osteoid and defective endochondrial ossification

39
Q

What is the etiology of rickets?

A

Vitamin D or phosphorus deficiency

Lack of sunlight (decrease vitD)

40
Q

What are the gross lesion of rickets?

A

Irregular thickening of growth plates with tongues of uncalcified cartilage extending into the metaphysics

Widening of growth plates ->.enlarged ends of long bones; enlargement of costocondrial junctions

Weight bearing long bones become bowed

Hemorrhage of articular cartilage or in growth plate

Pathological fracture

41
Q

What disease of adult animals is due to unmineralized osteoid that is resistant to osteoclastic reabsorption and accumulation in the bone?

A

Osteomalacia

42
Q

What is the etiology of osteomalacia?

A

Failure of mineralization due to vit D or P deficiency

43
Q

Mature animals with…
Shifting lameness (bone pain)
Pathological fractures
Deformities like kyphosis, lordosis, or scoliosis?

A

Osteomalacia

44
Q

What bone disease is characterized by extensive bone reabsorption and replacement by fibrous CT and poorly mineralized immature bone ?

A

Fibrous osteodystrophy

45
Q

What is the etiology of fibrous osteodystrophy?

A

Hormonal

Hyperparathyroidism (primary or secondary)

46
Q

What is primary hyperparathyroidism ?

A

Associated with parathyroid adenoma in dog

-> increased PTH = hypercalcemia and hypophsphatemia

47
Q

What is secondary hyperparathyroidism ?

A

Nutritional -> dietary deficiency of Ca/ vitD, or excess P => increase PTH

Renal -> P retention due to loss of glomerular function and inadequate synthesis of calcitriol => increase PTH

48
Q

What is the pathogenesis of lead poisoning leading to bone disease?

A

Lead interferes with osteoclastic activity -> subtle bone lesions -> increase bone density in the metaphysics -> “lead line”

49
Q

What is the pathogenesis of fluoride toxic osteodystrophy ?

A

Herbivores (mainly cattle and sheep) -> affect normal metabolism of bone and teeth -> ameoloblast and odontoblasts are markedly sensitive to excess Fourier and result in dark-brown discoloured teeth that wear down easily

Bones exhibit periosteal hyperostosis

50
Q

Cats that eat a high amount of bovine livers for a long period of time have what toxic osteodystrophies?

A

Hypervitaminosis A

51
Q

What is hypervitaminosis A toxic osteodystrophies ?

A

Deforming cervical spondylitis

Develop ostophyte formation around the joints of the cervical vertebrae, shoulder, and elbow

52
Q

What is the reaction of bone to ischemia ?

A

Necrosis -> bone ischemia associated with trauma/ inflammation/neoplastic bone disease

Cell death with loss of osteocytes for their lacunae

53
Q

What is the outcome of osteonecrosis?

A

Complete resorption and replace the of necrotic bone

“sequestrum” -> piece of necrotic bone isolated from remaining viable bone -> formation of granulation tissue and reactive bone called “involucrum”

54
Q

What type of bone fracture is due to normal bone broken by excessive force

A

Traumatic

55
Q

What type of bone fracture is due to abnormal bone broken by minimal trauma or normal weight bearing

A

Pathological

56
Q

What type of bone fracture is caused by the pull of a ligament or muscle tendon at its insertion?

A

Avulsed

57
Q

What is fracturing of trabeculae without external deformation of cortical bone called?

A

Micro-fracture/infraction

58
Q

How is a fracture repaired?

A

Blood clot in fracture site

Fibroblasts enter site
Blood vessels through the periosteum

Formation of cartilage and woven bone
Osteoclasts clean up debris

59
Q

What complications can be associated with bone fractures?

A

Bone necrosis and formation of sequestrum

Nonunion fracture-> pseudoarthrosis (false joint) formation

Osteomyelitis (compound fractures)

Cachexia