Bone tissue and structure

Question 1

Why can bone tissue be classified as living

Answer 1

It contains cells

Question 2

What does ECM stand for

Answer 2

Extracellular matrix

Question 3

What is bone tissue composed of

Answer 3

Connective tissue and the extracellular matrix

Question 4

What are the two components of the extracellular matrix

Answer 4

Organic and inorganic

Question 5

What percentage of the ECM is organic

Answer 5

33%

Question 6

What makes up the organic ECM

Answer 6

Collagen (protein) and proteoglycans

Question 7

Purpose of organic ECM

Answer 7

Provides flexibility to resist tension

Question 8

What percentage of the ECM is inorganic

Answer 8

67%

Question 9

What makes up the inorganic ECM

Answer 9

Hydroxyapatite and other Ca minerals

Question 10

Purpose of the inorganic ECM

Answer 10

Makes the bone hard and provides strength

Question 11

What percentage of bone weight do cells make up

Answer 11

2%

Question 12

Bone tissue contains what four cells

Answer 12

Osteogenic
Osteoblasts
Osteocytes (mature bone cells)
Osteoclasts

Question 13

What is the main purpose of the four cells

Answer 13

To maintain bone homeostasis

Question 14

What do osteogenic cells do

Answer 14

Stem cells that produce osteoblasts

Question 15

What do osteoblasts cells do

Answer 15

Makers - produce new bone matrix

Question 16

What do osteocytes cells do

Answer 16

Recycle protein and minerals from matrix (maintainers).
Control if bone needs to be produced or removed

Question 17

What do osteoclasts cells do

Answer 17

Remove bone matrix (destroyers)

Question 18

What is the structure of compact bone

Answer 18

Osteon structure

Question 19

What is the structure of cancellous bone

Answer 19

Trabecular structure

Question 20

What are the compact units that make up compact bone called

Answer 20

Osteons

Question 21

What are the 4 components of an osteon

Answer 21

Central canal
Lamallae
Lacunae
Canaliculi

Question 22

What is the central canal

Answer 22

Cavity in the center of the osteon containing blood vessels and nerves

Question 23

What is the lamallae

Answer 23

Series of cylinders formed of ECM around the central canal

Question 24

What is the lacunae

Answer 24

Lakes for osteocytes within the lamallae

Question 25

What is a canliculi

Answer 25

Channel for osteocytes through ECM

Question 26

Microscopic view of compact bone

Answer 26

Made up of circumferential lamallae and osteon units

Question 27

Macroscopic view of compact bone

Answer 27

• Dense and impenetrable
• Foramina for nerves and blood supply

Question 28

Cancellous bone microscopic structure

Answer 28

Trabeculae (branches of lamella bone)

Question 29

Where are Osteocytes located in cancellous bone

Answer 29

In lacuna in between lamallae

Question 30

Why does cancellous bone not contain a central canal

Answer 30

Blood vessels and nerves can get directly to osteocytes in the centre through the canaliculi

Question 31

Why do cancellous bones have a trabecular structure

Answer 31

• Resists force from multiple directions
• Directs force from body weight in single direction down shaft
• Spreads force distally

Question 32

What is appositional growth

Answer 32

Growth in the diameter of a bone

Question 33

How do bones grow and the diameter change

Answer 33

-Osteoblasts add bone matrix in lamallae to the bone surface
- Osteoclasts remove bone from the medullary cavity (center)

Question 34

What is bone homeostasis

Answer 34

Balance in osteoblast and osteoclast activity

Question 35

What is bone remodelling

Answer 35

• Possible shape change throughout life to resist strain.
• Possible through bone constantly being formed and destroyed