Osteochondrogenesis/Joints

Question 1

bone histogenesis

Answer 1

intramembranous & endochondral bone formation

Question 2

bone remodeling

Answer 2

bone formation & resorption

Question 3

what is a buffer for calcium?

Answer 3

bone

Question 4

what forms an errosion tunnel?

Answer 4

osteoclasts

Question 5

what cells start formation of new osteons (remodeling)?

Answer 5

osteoblasts

Question 6

where does remodeling occur?

Answer 6

inside compact bone & at bone surfaces

Question 7

cementing substance

Answer 7

laid down by osteoblasts on eroded surface; highly mineralized & little collagen

Question 8

intramembranous bone formation

Answer 8

process for flat bone formation ex: skull & facial bones, mandible, clavicle, pelvis; occurs in highly vascularized mesenchymal tissue

Question 9

primary ossification centers

Answer 9

made of condensed mesenchymal cells—>osteoblasts; secretion of osteoid collagen (woven bone)

Question 10

trabeculae

Answer 10

small spicules of developing bone; osteoblasts become entrapped in matrix with calcification and become osteoclasts

Question 11

spongy bone

Answer 11

fusion of trabeculae; blood vessels invade & undifferentiated mesenchymal cells develop bone marrow

Question 12

periosteum & endosteum made from?

Answer 12

mesenchymal cells that don’t undergo ossification

Question 13

endochondral bone formation

Answer 13

process of long bone formation

Question 14

what serves as a model for bone?

Answer 14

hyaline cartilage; two stages: primary & secondary ossification

Question 15

primary center of ossification?

Answer 15

midriff of diaphysis of cartilaginous model

Question 16

vascularization of perichondrium causes?

Answer 16

chondrogenic cells to transform into osteoprogenitor cells which differentiate into osteoblasts (periosteum)

Question 17

subperiosteal bone collar formed by?

Answer 17

osteoblasts by intramembranous bone formation; secretes collagen X & vascular endothelial growth factor

Question 18

periosteal buds

Answer 18

blood vessels, osteoprogenitor cells, & mesenchymal cells; enters primary marrow cavity, which calcifies cartilage

Question 19

calcified cartilage-calcified bone complex

Answer 19

bone matrix made & calcified on surface of calcified cartilage

Question 20

calcified cartilage stains?

Answer 20

basophilic

Question 21

calcified bone stains?

Answer 21

acidophilic

Question 22

subperiosteal bone collar does what?

Answer 22

thickens & elongates toward epiphyses

Question 23

what resorbs the calcified cartilage-calcified bone complex?

Answer 23

osteoclasts—>enlargement primitive marrow cavity

Question 24

secondary centers of ossification

Answer 24

develop at epiphyses after diaphyseal ossification center is established

Question 25

where is cartilage found when ephiphyses are filled with bone tissue?

Answer 25

articular surfaces and epiphyseal plate

Question 26

epiphyseal plate zones

Answer 26

zone of reserve, proliferation, cell hypertrophy & maturation, calcification, & ossification

Question 27

zone of reserve

Answer 27

small, randomly arranged; inactive chondrocytes

Question 28

zone of proliferation

Answer 28

interstitial growth; region of rapid mitotic divisions --->isogenous cell groups

Question 29

zone of cell hypertrophy & maturation

Answer 29

region where chondrocytes are enlarged

Question 30

zone of calcification

Answer 30

region where remnants of cartilage matrices become calcified & chondrocytes die

Question 31

zone of ossification

Answer 31

where bone is made upon calcified cartilage followed by resorption of calcified bone-calcified cartilage complex

Question 32

what happens during bone repair of a fracture?

Answer 32

proliferation of osteoprogenitor cells from periosteum & endosteum surrounding fracture; a callus forms internally & externally at fracture; fibrous CT & hyaline cartilage are formed in fracture; endochondral bone formation replaces cartilage with woven bone; primary bone resorbed & replaced with secondary (lamellar) bone

Question 33

bony callus

Answer 33

irregularly arranged trabeculae of primary bone joins ends of fracture

Question 34

how do hairline fractures heal?

Answer 34

via intramembranous bone formation at periosteal surface

Question 35

synarthroses joints

Answer 35

immovable joints composed of CT, cartilage, or bone; ex: first rib to sternum & skull bone connections

Question 36

amphiarthroses

Answer 36

slight movement; IV disks

Question 37

diarthroses

Answer 37

synovial joints; maximum movement. ex: long bones

Question 38

synovial joints contain?

Answer 38

2 layered capsule that encloses & seals articular cavity which contains synovial fluid

Question 39

what is synovial fluid?

Answer 39

colorless viscous fluid rich in hyaluronic acid & proteins

Question 40

external (fibrous) capsular layer

Answer 40

fibrous layer of dense CT

Question 41

internal (synovial) capsular layer

Answer 41

synovial membrane

Question 42

type A cells

Answer 42

phagocytic; well developed golgi & many lysosomes

Question 43

type B cells

Answer 43

resemble fibroblasts; well developed rER; probably secretes synovial fluid

Question 44

osteopetrosis

Answer 44

hereditary disease of abnormal osteoclast function; brittle bones, lack of lamellar bones due to lack of remodeling; no marrow cavity

Question 45

albers-schoenberg disease

Answer 45

marble bone disease; deficiency in carbonic anhydrase II. osteoclasts can't accumulate H+ in howships lacunae to activate acid requiring lysosomal enzymes

Question 46

osteoporosis

Answer 46

loss of bone mass of primary trabecular bone. normal resorption but decreased bone formation

Question 47

rheumatoid arthritis

Answer 47

inflammatory reaction in synovial tissue