Bones

Question 1

State the 4 functions of bone

Answer 1

Weight bearing/support

Protection

Mineral store

Blood formation

Question 2

The gross anatomy of the bone includes (6)

Answer 2

Compact bone

Spongy (trabecular)bone

Blood vessels

Medullary cavity

Bone marrow

Membrane (periosteum and endosteum)

Question 3

What is compact bone organised into?

Answer 3

Circular structures known as osteons surrounding a central Haversian canal

Question 4

What canals run horizontal in bone?

Answer 4

Volkmann’s canals

Question 5

What is found around a Haversian canal?

Answer 5

Osteocytes and concentric ring of bone matrix known as lamellae

Question 6

What are the other names for spongy bone? (3)

Answer 6

Trabecular

Cancellous

Diploe

Question 7

Compared to compact bone, spongy bone is ________ dense

Answer 7

Less

Question 8

What is spongy bone?

Answer 8

A network of lamellated trabeculae filled with bone marrow

Question 9

What does the orientation of trabeculae reflect?

Answer 9

Main directions of mechanical force

Question 10

State the 6 types of bone

Answer 10

Flat bone

Sutural bone

Short bone

Irregular bone

Sesamoid bone

Long bone

Question 11

What are the 2 types of bone development?

Answer 11

Endochondral

Intramembranous

Question 12

Explain the process of endochondral ossification

Answer 12

Cartilage models of bones are formed. Blood vessels then invade the cartilage. The cartilage is then replaced with bone. The cartilage remains in the epiphyseal growth plate and the growth plate eventually ossifies

Question 13

Explain the process of intramembranous ossification

Answer 13

There is no cartilaginous phase. Mesenchymal cells develop into osteoprogenitor cells that mature into osteoblasts that start depositing bone.
Residual mesenchymal cells develop blood vessels and bone marrow

Question 14

The bone formation that occurs in adult cortical bone is

Answer 14

Intramembranous ossification

Question 15

All bones are derived from

Answer 15

Mesenchyme (embryonic connective tissue)

Question 16

State what makes up bone

Answer 16

Cells which include osteocytes, osteoblasts and osteoclasts 
And extracellular matrix which includes 
~45% hydroxyapatite crystals 
~35% Collagen (Type I)
~20% Water

Question 17

What do minerals such as hydroxyapatite do in bone?

Answer 17

Makes bone stiff and able to support structures. Also gives high strength under compression
3 S’s - Stiffness, support and strength

Question 18

What does collagen do in bone?

Answer 18

Gives the bone high tensile strength and gives the bone flexibility and reduces the risk of fracture

Question 19

What makes a bone healthy?

Answer 19

A balance between bone removal and bone formation

Question 20

What are osteoblasts?

Answer 20

Immature bone cells created from osteoprogenitor cells in periosteum and endospteum

Question 21

State the function of osteoblasts

Answer 21

To produce bone matrix and initiate calcification

Question 22

What happens to osteoblasts when they become surrounded by matrix

Answer 22

They become osteocytes

Question 23

What are osteocytes?

Answer 23

Mature bone cells found inside lacunae

Question 24

What do canaliculi do?

Answer 24

Connect lacunae together and so allow communication between cells

Question 25

What are osteoclasts

Answer 25

Multinucleate cells derived from monocytes/macrophages

Question 26

Where are osteoclasts found?

Answer 26

Bone surface

Question 27

What is the function of osteoclasts?

Answer 27

To resorb bone matrix

Question 28

Name 3 disorders of bone remodelling

Answer 28

Osteoporosis, Paget’s Disease and Osteopotrosis

Question 29

What is bone mass controlled by?

Answer 29

Genes and environment (smoking, exercise and calcium intake)