Pathology Text Book - Bones And Joints

Front 1

what are osteoblasts?

Back 1

cells on any bone surface that produce bone matrix, initiate mineralization and initiate bone resorption

Front 2

what is the appearance of an active osteoblast?

Back 2

plump, lots of cytoplasm, RER, golgi and mitochondria

Front 3

how can osteoblast activity be indirectly measured?

Back 3

AlkPhos

Front 4

what is osteoid?

Back 4

bone matrix

Front 5

what is AlkPhos?

Back 5

alkaline phosphatase is an enzyme on the surface of osteoblasts. function unk, but has role in mineralization and pumping calcium across cell membranes.

Front 6

what is osteocalcin?

Back 6

protein secreted by osteoblast. found in bone matrix. correlates with osteoblast synthetic activity.

Front 7

what are osteocytes?

Back 7

osteoblasts surrounded by mineralized bone matrix. sit in lacunae.

Front 8

what is osteocytic osteolysis?

Back 8

process of enlarging lacunae. not very common.

Front 9

what are osteoclasts?

Back 9

multinucleated cells that resorb bone

Front 10

how to osteoclasts resorb bone?

Back 10

osteoclasts must access bone surface, attach to mineralized material, bind ligands and secrete H+ and lysosomal contents.

Front 11

what enzymes do osteoclasts release to resorb bone?

Back 11

- cysteine

- metalloproteinases

- cathpsins

Front 12

what is the effect of calcitonin on osteoclasts.

Back 12

a systemic inhibitor

Front 13

how to osteocytes and osteoblasts interact?

Back 13

osteocytes and osteoblasts are connected by cytoplasm. form a membrane that regulates movement of calcium and phosphate ions.

Front 14

how do osteoclasts and osteoblasts interact?

Back 14

regulate physiologic bone resorption.

Front 15

what is the organic bone matrix made of?

Back 15

- type I collagen

- ground substance

Front 16

what is type I collagen?

Back 16

type I collagen is secreted by osteoblasts

- made up of 3 intertwined aa chains with extensive cross linking

Front 17

what is ground substance?

Back 17

noncollagenous extracellular fluid made up of PSGAGS, proteoglycans, GAGs, lipids and noncollagenous proteins. produced by osteoblasts

Front 18

what is hydroxyappetite?

Back 18

a crystal that makes up 65% of a bone by weight.

made of ca, phos, carbonate, magnesium, sodium, manganese, zn, cu, fluoride.

the substance which gives bone its hardness

Front 19

what initiates osteoid mineralization?

Back 19

osteoid mineralization in woven bone is initiated by cytoplasmic blebs of osteoblasts. the blebs are filled with minerals that precipitate to form amorphus hydroxyappetite.

Front 20

what are osteons?

Back 20

osteons or haversian systems are bone organizations in the compact bone

Front 21

what are interstitial lamella?

Back 21

the area between osteons

Front 22

what are circumferential lamella?

Back 22

layers of bone parallel to internal and external circumference of bone

Front 23

what is the osteonal system?

Back 23

channels that provide vascular supply and help limit microcrack propegation

Front 24

what is bone remodeling?

Back 24

low constant replacement

Front 25

what is the remodeling unit of cortical bone?o

Back 25

osteon

Front 26

what are cement lines?

Back 26

peripheral remodeling units. no collagen fibers extend across the cement line, allowing some movement

Front 27

what are reversal lines?

Back 27

cement lines showing limit of previous resorptive activity are scalloped.

Front 28

what are resting lines?

Back 28

where osteoblasts stop forming and later resume. they are smooth and follow the contour of the surface.

Front 29

what is bone modeling?

Back 29

change shape or contour of bone in response to normal growth, altered use or disease

Front 30

what process to flat bones use to form?

Back 30

intramembranous ossification.

Front 31

what is intramembranous ossification?

Back 31

mesenchymal cells differentiate into osteoblasts and produce bone directly. no cartilage precursor.

Front 32

what is endochondral ossification?

Back 32

bone forming around a cartilage template. template is invaded by vessels, ossification centers develop.

Front 33

how is blood supplied to the bone?

Back 33

- nutrient arteris

- proximal and distal metaphyseal arteries

- periosteal arteries

- epiphyseal arteries

Front 34

How do nutrient arteries enter bones?

Back 34

penetrate cortex of diaphysis through nutrient foramen. branch and divide in medullary cavity.

Front 35

how do proximal and distal metaphyseal arteries enter bones?

Back 35

penetrate cortex and anastamose with nutrient artery in the medullary cavity.

Front 36

how to periosteal arteries enter bones?

Back 36

pass through diaphyseal cortex.

Front 37

what do periosteal arteries supply?

Back 37

1/4 to 1/3 of the outer cortex.

Front 38

what do epiphyseal arteries supply?

Back 38

chondrocytes in physis nearest to epiphysis.

Front 39

what supplies the chondrocytes not supplied by epiphyseal arteries?

Back 39

nutrient and metaphyseal artery branches

Front 40

what is centrifugal blood flow?

Back 40

blood in bones flows from medulla to periosteum

Front 41

which growth plate is primarily responsible for bone elongation?

Back 41

metaphyseal growth plates

Front 42

what are the zones of cartilage?

Back 42

- reserve/resting

- proliferative

- hypertrophic

- maturation

- degeneration

- calcification

Front 43

why is vascular invasion key to bone mineralization?

Back 43

vascular invasion supplies the necessary mineral salts.

Front 44

what is the chondrosseous junction?

Back 44

fragile lattice of bone covered by spicules of calcified cartilage in the metaphysis.

Front 45

what is the AE complex?

Back 45

zone of endochondral ossification beneath articular cartilage in growing animals.

Front 46

what are the functions of joints?

Back 46

- join skeletal structures

- provide movement

- shock-absorption

Front 47

what are synovial joints?

Back 47

synovial joints are found in both axial and appendicular skeletons. have variable degrees of movement. Made of two bone ends bund by fibrous capsule and ligaments

Front 48

what lines the inner articular surface of synovial joints?

Back 48

synovial membrane

Front 49

what is found in the joint space of synovial joints?

Back 49

- synovial fluid

- fibrocartilage menisci/disks

Front 50

what are synovial fossae?

Back 50

normal depression in non-weight bearing cartilage. develop bilaterally in large appendicular joints of large animals. unknown function. easy to mistake for lesions.

Front 51

what are tide marks?

Back 51

junctions between unmineralized articular cartilage and deeper mineralized cartilage.

Front 52

what is aggregin?

Back 52

made of chains of long non-polysulfacted GAGs with core proteins attached. smaller PSGAGs attached to core proteins. binds water to make a hydrated gel.

Front 53

what is the function of the superficial zone of articular cartilage?

Back 53

resists shearing forces. made up of type I cartilage.

Front 54

what is the function of the middle zone of articular cartilage?

Back 54

shock absorption

Front 55

what is the function of the deep mineralized zone of articular cartilage?

Back 55

attaches cartilage to the subchondral bone

Front 56

what are the two layers of the articular capsule?

Back 56

outer fibrous synovial layer

inner synovial membrane

Front 57

what is the outer fibrous synovial layer?

Back 57

a heavy sheath that stabilizes the joint. has a rich vascular and nerve supply.

Front 58

what is the inner synovial membrane?

Back 58

a very thin layer with villous surface.

Front 59

what makes up synovial fluid?

Back 59

plasma dialystate

supplemental proteoglycans

Front 60

what are the two lubrication processes in synovial joints?

Back 60

- weeping (squeeze film)

- boundary lubrication

Front 61

what is weeping (squeeze film) lubrication?

Back 61

pressurized fluid carries most of the load in a weighted joint. when pressure is released, fluid reenters cartilage (proteoglycans create inward draw).

Front 62

what are the functions of subchondral bone?

Back 62

supports overlying cartilage

dissipates concussion

Front 63

what does primary trabeculae alteration indicate?

Back 63

disrupted endochondral ossification

Front 64

what are growth arrest lines?

Back 64

an alteration of primary trabeculae. seen with poor nutrition or debilitating disease. plate is narrowed, and bony layer seals the metaphyseal face.

Front 65

what is a growth retardation lattice?

Back 65

an alteration of primary trabeculae. acquired osteoclast activity impairment. can be due to distemper, BVD, lead toxicosis.

Front 66

what is wolff's law?

Back 66

the ability of bone to model, remodel and change shape is based on tension, compression, and stress placed upon it.

Front 67

what is streaming potential?

Back 67

electrical current in bone. caused by fluid flux in canaliculi.

Front 68

what is cutback zone?

Back 68

where bone tapers from physeal diameter to diaphysis diameter. site of marked osteoclastic bone resorption from periosteum during growth.

Front 69

how does articular cartilage respond to damage?

Back 69

articular cartilage has minimal capability for repair. damage will persist for prolonged periods of time.

Front 70

what replaces articular cartilage defects extending into subchondral bone?

Back 70

fibrocartilage

Front 71

what causes sterile joint injuries?

Back 71

trauma

joint instability

lubrication failure

Front 72

what is the appearance of damage articular cartilage?

Back 72

yellow-brown, dull and rough

Front 73

what substances are increased during joint inflammation and DJD?

Back 73

PG, NO, TNF-alpha, substance P, neurotransmitters

Front 74

what is the effect of PG and NO on joints?

Back 74

inhibit proteoglycan synthesis. cartilage degenerates and is lost

Front 75

what is the effect of IL-1 and TNF-alpha on cartilage?

Back 75

promote PG and NO secretion. decreased matrix synthesis and increase its destruction.

Front 76

which factors are anabolic to cartilage?

Back 76

IL6, TGF-beta, insulin-like growth factor

Front 77

what are joint mice?

Back 77

free floating detached cartilage pieces in the joint

Front 78

what happens to subchondral bone when proteoglycans are lost?

Back 78

increased concussive forces are transmitted to subchondral bones.

Front 79

how does subchondral bone response to increased concussive forces?

Back 79

decreases resorption, increase formation

Front 80

what is eburnation?

Back 80

full articular cartilage ulceration results in polished, dense subchondral bone

Front 81

what is osteopetrosis?

Back 81

increased bone density per unit area (sclerotic bone). aka metaphyseal dysplasia.

Front 82

what causes osteopetrosis?

Back 82

failure of osteoclasts to resorb bone. seems to be spontaneous with a potential genetic link.

Front 83

what is osteogeneis imperfecta?

Back 83

reduced bone mass disease. a defect in production of type I collagen. more prone to fx.

Front 84

what is congenital cortical hyperostosis?

Back 84

an autosomal recessive dz in pigs that results in abnormal periosteal bone formation on long bones. allows GP to expand in diameter.

Front 85

what is craniomandibular osteopathy?

Back 85

aka "lion jaw". related to leukocyte adhesion deficiency. bilateral lesions in mandible, occipital and temporal bones, causing increased density and prolific woven bone production.

Front 86

what are chondrodystrophies?

Back 86

diseases of bone growth due to growth cartilage lesions.

Front 87

what is osteochondrosis?

Back 87

heterogeneous group of lesions in growth cartilage. characterized by multifocal failure of endochondral ossification.

Front 88

what is OCD?

Back 88

dysplasia at AE complex. forms clefts in retained cartilage, subsequent fx of articular cartilage above, resulting in flaps that can fracture off and become joint mice.

Front 89

what is epiphysiolysis?

Back 89

seperation of epiphysis and metaphysis due to tissue forming hoizontally thorugh physis. horizontal fractures.

Front 90

what is cervical vertebral myelopathy?

Back 90

static/dynamic cord compression due to abnormal vertebrae

Front 91

what are the common metabolic bone diseases?

Back 91

- osteoporosis

- osteomalacia

- rickets

- fibrous osteodystrophy

Front 92

what causes osteoporosis?

Back 92

malnutrition

excess glucorticoid

Front 93

what causes osteomalacia?

Back 93

vitamin D and phosphorous deficiency

Front 94

what causes rickets?

Back 94

vit D and phosphorous deficiency

Front 95

what causes fibrous osteodystrophy?

Back 95

hyperparathyroidism

- chief cell adenoma (paraneoplastic sydrome)

- nutritional hyperparathyroidims

- secondary renal hyperparathyroidism

Front 96

what are characteristics of osteoporosis?

Back 96

reduced bone mass

porous, thin, brittle bones

Front 97

what are characteristics of osteomalacia?

Back 97

decreased bone mineralization, soft bones

Front 98

what are characteristics of rickets?

Back 98

decreased mineralization, soft bone with thick growth plates.

Front 99

what are characteristics of fibrous osteodystrophy?

Back 99

decreased bone mass with replacement by fibrous tissue. rubbery bones.

Front 100

what is osteitis?

Back 100

bone inflammation

Front 101

what is periosteitis?

Back 101

periosteal inflammation

Front 102

what is osteomyelitis?

Back 102

chronic necrosis and removal of bone over time. disfiguring.

Front 103

what is hypertrophic osteodystrophy?

Back 103

non-infectious bone inflammation.

Front 104

what lesions are seen with hypertrophic osteodystrophy?

Back 104

suppurative and fibrinous osteomyelitis of trabecular bone in metaphysis.

Front 105

what are enthesophytes?

Back 105

nodular, benign bony growths projecting outwards from bone surface. non-neoplastic.

Front 106

what are enthesophytes?

Back 106

osteophytes located at tendon insertion point

Front 107

what is hyperostosis?

Back 107

increased bone diameter due to uniform periosteal thickening

Front 108

what is enostosis?

Back 108

bony growth WITHIN the medullary cavity. non neoplastic.

Front 109

what is osteochondroma?

Back 109

multiple cartilaginous exostoses.

Front 110

where are osteochondromas most often seen?

Back 110

ribs, vertebrae, scapula, pelvic bones

Front 111

what is fibrous dysplasia?

Back 111

an uncomon intraosseous lesion, focal/multifocal. seen in young animals.

Front 112

what are simple bone cysts?

Back 112

cyst walls made of fibrous tissue and woven lamellar bone, filled with serum like fluid.

Front 113

what are aneurysmal bone cysts?

Back 113

fibrous to fibroosseous walls filled with blood/serosanguinous fluid

Front 114

what is ossifying fibroma?

Back 114

an uncommon benign primary bone neoplasia. seen in jaw of horses and cows. mass expansion causes damage of adjacent tissue.

Front 115

what is fibrosarcoma?

Back 115

a primary bone neoplasm. malignancy of fibroblasts.

Front 116

what is a chondroma?

Back 116

benign primary bone neoplasm. tumor of hyaline cartilage.

Front 117

what is a chondrosarcoma?

Back 117

malignant primary bone neoplasm. growth produces cartilaginous matrix.

Front 118

what is an osteoma?

Back 118

benign primary bone tumor. tend to arise from skull, jaw.

Front 119

what is an osteosarcoma?

Back 119

malignant primary bone neoplasm, producing bone and/or osteoid

Front 120

what is a common secondary bone neoplasm in cats?

Back 120

asymptomatic pulmonary carcinoma

Front 121

what is a pathologic fracture?

Back 121

abnormal bone that fractures under normal force or minimal trauma.

Front 122

what is a traumatic fracture?

Back 122

normal bone that fractures under excessive force

Front 123

what is a salter-harris I fx?

Back 123

fracture of the hypertrophied cartilage layer

Front 124

what is a salter-harris II fx?

Back 124

fracture involving the primary trabeculae

Front 125

what is a salter-harris III fx?

Back 125

fx that crosses the growth plate and heals with secondary deformities

Front 126

what is a salter-harris IV fx?

Back 126

fx that crosses the GP and heals with secondary deformities.

Front 127

what is a salter-harris V fx?

Back 127

a crushing trauma that heals with secondary deformities

Front 128

what is a salter-harris VI fx?

Back 128

a crushing trauma that heals with secondary deformities

Front 129

what repairs occur 24-48 hours post fx?

Back 129

undifferentiated mesenchymal cells and reactive vascular proliferation penetrate the hematoma

Front 130

what fracture repairs occur 36 hours post fx?

Back 130

woven bone forms, nerve fibers regnerate

Front 131

what is a fx callus?

Back 131

unorganized mesh of woven bone. can be internal or external. bridges the fx and stabilizes ti.

Front 132

what fx repairs occur 4-6 weeks after injury?

Back 132

callus of woven bone and hyaline cartilage forms

Front 133

how long does it take woven bone laid down during fx repair to become lamellar bone?

Back 133

months-years

Front 134

how do rigid fx repairs occur?

Back 134

direct osteonal bridging. lamellar bone forms at 90 degree angle to fx line.

Front 135

what is arthrogryposis?

Back 135

congenital joint contracture. bilateral and congenital.

Front 136

what are potential causes of arthrogyrposis?

Back 136

- viruses that damage fetal CNS (bluetongue, akabane)

- toxic teratogenic plants (lupine, poison hemlock)

- positional abnormality

Front 137

what is synovitis?

Back 137

inflammation of synovium

Front 138

what is rheumatoid arthritis?

Back 138

a chronic, sterile, erosive polyarthritis

Front 139

what is gout?

Back 139

urate crystals deposited in/around joint and causes synovitis

Front 140

what is DJD?

Back 140

degenerative joint disease is a destructive dz of articular cartilage in synovial joints

Front 141

what is joint ankylosis?

Back 141

fibrous or bony bridging of joint

Front 142

what is intervertebral disk degeneration?

Back 142

age related change where central disk is replaced by fibrocartilaginous material

Front 143

what are the common neoplasms of joints?

Back 143

histiocytic sarcoma

synovial cell sarcoma