May- Bone

Question 1

what makes up the organic part of bone?

Answer 1

fibrous and ground substance

Question 2

what types of inorganic materials are present in bone?

Answer 2

Ca, phosphorus abundant

Mg, Na, K, citrate, bicarbonates

Question 3

what molecules are mainly responsible for the formation of the hydroxyapatite crystals?

Answer 3

Calcium and phospohorus

Question 4

does bone contain blood vessels?

Answer 4

yes (it is essential for cell nutrition)

Question 5

does the periosteum cover the articular surfaces of bones?

Answer 5

no

Question 6

what cells does the outer layer of periosteum contain?

Answer 6

collagen fibers, fibroblasts, mesenchymal cells

Question 7

what is in the inner layer of the periosteum?

Answer 7

osteoblasts, mesenchymal cells and some collagen fibers

Question 8

how does the periosteum connect to the bone?

Answer 8

Sharpey’s fibers.

Question 9

what layer contains reticular fibers and lines the marrow cavity?

Answer 9

endosteum

Question 10

how are osteoblasts formed?

Answer 10

mesenchymal cells differentiate into osteoblasts

Question 11

how are lacunae and canaliculi formed during intramembranous formation?

Answer 11

osteoblasts secrete osteoid which surround the osteoblast and their cytoplasmic processes.

Question 12

what is it called when osteoid calcifies?

Answer 12

ossification

Question 13

the continuous ossification process yields trabeculae. how do the trabeculae grow?

Answer 13

trabeculae form radially from the center of ossification

Question 14

when trabeculae enlarge, approximate each other and trap blood vessels, what is formed?

Answer 14

compact bone

Question 15

what allows for appositional growth of the bone?

Answer 15

periosteum

Question 16

what is endochondral formation?

Answer 16

using a cartilage template (hyaline model) that is replaced by bone

Question 17

what is formed when the perichondrium is transformed into a periosteum and osteoblasts lay down osteoid?

Answer 17

bone collar

Question 18

calcification occurs when which cells start to hypertrophy and secrete a phosphatase?

Answer 18

chondrocytes

Question 19

in what part of the shaft is the formation of primary center of ossification occuring?

Answer 19

diaphysis (center of the shaft)

Question 20

where does formation of secondary center of ossification occur?

Answer 20

epiphyses (and continues in the radial direction until only a thin rim of cartilage remains)

Question 21

what separates the epiphysis from the diaphysis?

Answer 21

the epiphyseal plate

Question 22

after bone has replaced cartilage, what two areas still contain cartilage?

Answer 22

the articular ends and the epiphyseal plate

Question 23

name the growth zones of the epiphyseal plate.

Answer 23

resting, proliferative, hypertrophy, calcification, retrogression, ossification (know these zones and how they grow)

Question 24

how do phosphatases affect lacunae?

Answer 24

they calcify the rims of lacunae, which leads to death of chondrocytes

Question 25

what leads to closure of the epiphyseal plate?

Answer 25

when interstitial growth ceases

Question 26

does bone usually continue to grow in thickness?

Answer 26

it remains faily constant but diameter of bone and marrow cavity continue due to osteogenic activity

Question 27

what types of bone lack lamellae and have collagen arranged in irregular fashion?

Answer 27

immature, primary and woven bone

Question 28

what type of bone have collagen fibers arranged parallel to each other?

Answer 28

mature, secondary and lamellar

Question 29

what contain a neurovascular bundle in the osteon?

Answer 29

central haversian canal

Question 30

what is an osteon?

Answer 30

structural unit of bone

Question 31

don inner and outer circumferential lamellae contain a haversian system?

Answer 31

nope

Question 32

what interconnects haversian canals and has the same contents as haversian canals?

Answer 32

volkmann canals

Question 33

what is the purpose of the volkman canals?

Answer 33

pathway for blood vessels from periosteum and endosteum to enter the haversian canals

Question 34

during bone remodeling what cell is responsible for the resorption of bone?

Answer 34

osteoclasts

Question 35

what grooves are formed when osteoclasts begin to erode bone?

Answer 35

Howship's Lacunae

Question 36

what is secreted to break down bone during osteolysis?

Answer 36

acid phosphatase and proteolytic enzymes

Question 37

what step in fracture repair is there connective tissue (fibroblasts, blood, macrophages and fibers) filling the space

Answer 37

procallus

Question 38

what is it called when connective tissue is replaced by hyaline cartilage?

Answer 38

temporary callus

Question 39

what is it called when cartilage is replaced by immature bone?

Answer 39

callus

Question 40

what replaces immature bone?

Answer 40

mature bone

Question 41

what increases serum calcium by stimulating the formation of osteoclasts?

Answer 41

parathyroid hormone

Question 42

what thyroid secretion lowers serum calcium by increasing osteoblastic activity?

Answer 42

calcitonin

Question 43

what increases calcium and phosphate absorption in the intestines?

Answer 43

vitamin D

Question 44

lack of vitamin D leads to what disease?

Answer 44

rickets and osteomalacea

Question 45

what is important for production of collagen and necessary for proper bone formation?

Answer 45

vitamin C

Question 46

what disease would you get from lack of vitamin C?

Answer 46

scurvy

Question 47

why do we need growth hormone?

Answer 47

signals proper growth of epiphyseal plate