Bone

Question 1

Types of bone

Answer 1

flat, short, long, sesamoid, irregular, sutural

Question 2

Functions of bone

Answer 2

weight bearing, protection, blood formation, mineral store

Question 3

osteons

Answer 3

compact bone organised in circular structures

Question 4

Haversian canals

Answer 4

runs inside osteons

Question 5

osteocytes and concentric rings of bone matrix

Answer 5

wrap around Haversian canals and are the inside of osteons

Question 6

other names for spongy bone

Answer 6

trabecular

Question 7

what is in spongy bone

Answer 7

network of lamellated trabeculae filled with bone marrow. no Haversian canals

Question 8

orientation of trabeculae reflects

Answer 8

main direction of mechanical forces

Question 9

cells in bone

Answer 9

osteocytes, osteoblasts, osteoclasts

Question 10

extracellular matrix of bone made up of

Answer 10

45% hydroxyapatite crystals (calcium phosphate), 35% collagen, 20% water

Question 11

what are the minerals in bone for

Answer 11

make bones stiff, able to support structures, high strength under compression

Question 12

what is collagen in bone for

Answer 12

gives bone some flexibility, reduces risk of fracture, high strength under tension

Question 13

membrane on bones

Answer 13

periosteum, endosteum

Question 14

what structures do bones contain

Answer 14

cortical bone, trabecular bone, blood vessels, medullary cavity, bone marrow, membranes

Question 15

How does bone turnover work

Answer 15

osteoclasts on surface break down bone by releasing acids from ruffled border creating a resorption pit, osteoblasts build up again and produce bone matrix (osteoid unmineralised) and then initiate calcification. osteoblasts become osteocytes

Question 16

where do osteocytes stay

Answer 16

lacunae connected by canaliculi which allows communication between cells

Question 17

what type of collagen is in EM of bone

Answer 17

type 1

Question 18

diseases where bone turnover doesn’t work

Answer 18

osteoporosis too much resorption, pagets disease too much resorption and formation, osteopetrosis not enough resorption

Question 19

ossification

Answer 19

bone formation

Question 20

types of ossification

Answer 20

endochondral and intramembranous. most bones are formed by combination of both

Question 21

endochondral ossification

Answer 21

bone forms as cartilage model first then blood vessels invade the cartilage, cartilage is replaced with bone and the cartilage remains in epiphyseal growth plate and then growth plate eventually ossifies

Question 22

intramembranous ossification

Answer 22

mesenchymal cells develop into osteoprogenitor cells that mature into osteoblasts. found in periosteum and endosteum. residual mesenchymal cells develop blood vessels and bone marrow. occurs in adults too

Question 23

two types of bone growth

Answer 23

appositional and interstitial

Question 24

appositional growth

Answer 24

osteoblasts on outside and osetoclasts on inside

Question 25

interstitial growth

Answer 25

growth from the epiphyseal growth plate