Bones

Question 1

What are osteoprogenitor cells

Answer 1

Stem cells that give rise to osteoblasts

Question 2

What is the function of osteoblasts?

Answer 2

To produce bone

Question 3

What is the Function of osteoclasts?

Answer 3

Resorption of bone

Question 4

What is in the extracellular matrix of bone

Answer 4

Calcium hydroxyapatite

Question 5

What does calcium hydroxyapatite do

Answer 5

Give strength to bones

Question 6

What are osteoprogenitor cells derived from

Answer 6

Mesenchyme

Question 7

What secretes osteoid

Answer 7

Osteoblasts

Question 8

What is osteoid

Answer 8

Unmineralised bone

Question 9

How are osteocyte connected

Answer 9

Canaliculi which supplies the blood

Question 10

What are osteoclasts derived from

Answer 10

Monocytes

Question 11

What histological feature does osteoclast absorption of bone produced

Answer 11

Howship’s Lacunae

Question 12

What are Howship’s Lacunae?

Answer 12

Depressions in the surface of bone

Question 13

What are the modes of bone formation

Answer 13

Membranous or endochondrial

Question 14

What are the origins of bone

Answer 14

Primary (woven)

Secondary (lamellar)

Question 15

What is Osteoid?

Answer 15

An extracellular matrix rich of type 1 collagen, glycosaminoglycans and proteoglycans 

Question 16

What do glycosaminoglycans include?

Answer 16

Compounds such as osteocalcin  which has a high affinity for calcium ions

Question 17

What do parallel sheets of osteoid produce?

Answer 17

Lamellar bone

Question 18

How is woven bone produced?

Answer 18

Osteoid produced rapidly by osteoblasts

Question 19

When is woven bone produced?

Answer 19

In fetal life and at fracture site

Question 20

When does osteoid mineralise

Answer 20

When there is a high local concentration of calcium and phosphate ions

Question 21

What enzyme aids mineralisation of osteoid?

Answer 21

Alkaline phosphatase

Question 22

What does osteocalcin do

Answer 22

Binds calcium ions to Osteoid.

Question 23

What is calcium deposited in bone as?

Answer 23

Calcium hydroxyapatite

Question 24

What is in secondary bone?

Answer 24

Central Haversian Canal containing blood vessels

Concentric rings of lamellar bone with entrapped osteocytes

Question 25

Which bones form from intramembranous ossification

Answer 25

Flat bones of the skull

Question 26

Which bones form from endochondral ossification

Answer 26

All except flat bones of the skull and some cortical bones

Question 27

Where are secondary centres of ossification

Answer 27

In the head or epiphysis of bones

Question 28

What are synovial joints lined by

Answer 28

``` Hyaline cartilage (articulated surface) Synovium (inner surface) ```

Question 29

What are type A synovial cells

Answer 29

Phagocytes

Question 30

What are type B synovial cells

Answer 30

Rich in rough endoplasmic reticulum and secrete synovial fluid