bone

Question 1

Definition of Bone

Answer 1

connective tissue characterized by a mineralized ECM

Question 2

What is the ECM of bone

Answer 2

hydroxyapatite crystals
type 1 collagen
small amt of type 5
glycoproteins (ostecalcin,nectin and pontin)

Question 3

Cells of BONE

Answer 3

osteocyte
osteoblast
osteoprogenitor cells
osteoclast

Question 4

What is the function of bone

Answer 4

support
protection
storage site for calcium and phosphate

Question 5

Endosteum

Answer 5

covers the inner surface of the marrow cavity and contains osteoprogenitor and endosteal cells that become osteocytes

Question 6

Components of bone

Answer 6

bone tissue
hemopoietic tissue
fat tissue
dense connective tissue 
vessels and nerves
endosteum

Question 7

examples of long bones

Answer 7

diaphysis, epiphysis, metaphysis, tibia and metacarpals

Question 8

examples of short bones

Answer 8

carpal bones

Question 9

examples of flat bones

Answer 9

skull cap and sternum

Question 10

examples of irregular bones

Answer 10

complex shape like vertabra

Question 11

haversian lamellae

Answer 11

concentrical lamellae surrounding a haversian canal that forms cylindrical units called osteon; haversian canals contain vessels and nerves
lacunae are between the lamellae with osteocytes
canaliculi penetrate lamellae with osteocytic processes

Question 12

interstitial lamellae

Answer 12

between osteon space filled with old haversian systems (remodling bone)

Question 13

outer circumferential lamellae

Answer 13

lining the outersurface of the bone under the periosteum

Question 14

inner circumferential lamellae

Answer 14

lining the inner surface of the bone under the endosteum

Question 15

Where is immature bone found

Answer 15

developing fetus, alveolar sockets, tendon attachments

Question 16

characteristics of immature bone

Answer 16

nonlamellar
more cell rich than mature bone
cells randomly organized
matrix is less mineralized and has more ground substance than mature bone
stains more basophilic

Question 17

What is periosteum

Answer 17

collagenous membrane on the outersurface of the bone

carries vessels and nerves which contain nocireceptros

Question 18

what are the two layers of the periosteum

Answer 18

outer fibrous layer that has dense irregular connective tissue
inner osteogenic layer: osteoprogenitor cells

Question 19

endosteum

Answer 19

covers the marrow cavity composed mostly of osteoprogenitor cells

Question 20

characteristic of osteoprogenitor cells

Answer 20

resemble fibroblasts
basophilic
located in the inner layer periosteum, endosteum and line the haversian and volkmanns canals
can divide and differentiate to osteoblasts and other things
participate in appositional bone formation

Question 21

osteoblasts

Answer 21

secretory cells capable of division
secrete ground substance and collagen
basophilic cytoplasm-RER
form a single cuboidal cell layer on surface of bone
secrete vesicles containing alkaline phosphatase

Question 22

when an osteoblast is surrounded by an osteoi it is called a

Answer 22

osteocyte

Question 23

osteocytes

Answer 23

surrounded by osteoid or mineralized bone
matains matrix
communicate via gap junctions and occupy canaliculi

Question 24

inactive osteocytes

Answer 24

few organelles

Question 25

formative osteocytes

Answer 25

RER

Question 26

resorptive osteocytes

Answer 26

lysosomes

Question 27

osteoclast

Answer 27

``` multinucleated acidophilic cells originate from monocytes nuclei on side ruffled border rest in a resorption bay decalcify bone with lysosomal hydrolases PTH increases osteoclast activity ```

Question 28

intramembranous ossification occurs when

Answer 28

fractures and embryo skull bone

Question 29

Endochondral ossification

Answer 29

starts with hyaline cartilage modle perichondrium forms bony collar primary ossification center develops chondrocytes become hypertrophic and secrete alkaline phosphatase inhibits diffusion of nutrients so death of suicidal cells death of chondrocytes-matrix breaks down to form a cavity capillary loop breaks into bone carrying osteoprogenitor cells that settle on surface of cartilage trabecules--osteoblasts osteoblasts build bone secondary ossification centers capillary loop breaks into the epiphysis

Question 30

how does bone increase in diabeter

Answer 30

appositional growth