Microscopic Bone Anatomy

Question 1

osteogenic cells

Answer 1

mitotically active stem cells

Question 2

osteogenic cells location

Answer 2

endosteum, periosteum

Question 3

what happens when osteogenic cells are stimulated?

Answer 3

differentiate into osteoblasts or bone lining cells

Question 4

osteoblasts

Answer 4

• secrete unmineralized bone matrix AKA osteoid
• actively mitotic

Question 5

what kind of cell is responsible for bone growth?

Answer 5

osteoblasts

Question 6

osteocytes

Answer 6

• mature cells
• monitors/maintains bone matrix

Question 7

osteocytes location

Answer 7

lacunae

Question 8

what cell acts as stress/strain detectors?

Answer 8

osteocytes

Question 9

line of communication when stress occurs

Answer 9

osteocytes -> osteoblasts and clasts

Question 10

periosteal bone lining cells

Answer 10

flat cells on outside of bone matrix, maintains structure

Question 11

endosteal bone lining cells

Answer 11

flat cells on inside of bone matrix, maintains structure

Question 12

osteoclast

Answer 12

• resorbs bone (eats it)
• multinucleate
• ruffled border for increased SA

Question 13

osteon

Answer 13

• hollow tube of bone matrix called lamellae
• elongated cylindrical, parallel to length of bone

Question 14

osteons resist twisting by

Answer 14

adjacent rings have their collagen fibers run in different directions

Question 15

central (Haversian) canal

Answer 15

• innermost canal in an osteon
• blood vessels and nerve fibers

Question 16

perforating (Volkman’s) canals

Answer 16

connects blood vessels from outside with inside

Question 17

lacunae

Answer 17

small cavities containing osteocytes

Question 18

canaliculi

Answer 18

hairlike canals that connect each perforating canal to each other and ultimately its central canal

Question 19

how is canaliculi formed

Answer 19

osteoblasts’ bone matrix becomes hardened in some places after being used as a route of communication many times

Question 20

interstitial lamellae

Answer 20

• incomplete
• not part of osteon
• fills gaps in between forming osteons

Question 21

what is interstitial lamellae a remnant of?

Answer 21

osteons cut by bone remodeling

Question 22

circumferential lamellae

Answer 22

circles around the entire circumference of bone structure (all Haversian systems)

Question 23

trabeculae

Answer 23

• no osteons
• irregularly arranged lamellae
• osteocytes connected by canaliculi

Question 24

osteoid

Answer 24

bone matrix material secreted by osteoblasts

Question 25

organic components of bones

Answer 25

osteogenic cells, osteoblasts, osteoclasts, osteocytes, bone-lining cells, and osteoids

Question 26

sacrificial bonds

Answer 26

• gives bone its resilience
• in or between collagen fibers
• release stress energy by breaking the bonds, will reform with time

Question 27

hydroxyapatites

Answer 27

• mineral salts
• 65% of bone by mass