The Skeletal System 1

Question 1

List 5 functions of the skeleton…

Answer 1

1. Structural support,
2. Protects internal organs,
3. Provides leverage for movement,
4. Stores calcium,
5. Produces blood cells.

Question 2

Bone is dynamic… What does this mean?

Answer 2

It changes as it is living tissue.

Question 3

Bone is a specialised form of what type of tissue?

Answer 3

Connective.

Question 4

Why does bone need to be strong and flexible?

Answer 4

To carry body weight.

Question 5

What is the organic component within the bone matrix?

Answer 5

Osteoid - made up of collagen and polypeptide chains.

Question 6

List some properties of the organic component of bone matrix…

Answer 6

Strong, Flexible and easily compressed.

Question 7

What is the inorganic component within the bone matrix?

Answer 7

Hydroxyapatite - deposition of mineral salts, mainly calcium phosphate and calcium carbonate.

Question 8

List some properties of the inorganic component of bone matrix…

Answer 8

Hard, Inflexible and brittle.

Question 9

What is an osteoblast?

Answer 9

They produce new bone - secrete osteoid and are responsible for mineral deposition.

Question 10

What are osteocytes?

Answer 10

Mature osteoblasts - Located within lacunae, maintain the matrix.

Question 11

What are osteoclasts?

Answer 11

Remove minerals from the matrix - responsible for bone remodelling.

Question 12

What are osteogenic stem cells?

Answer 12

Found in periostem and endosteum - Develop into osteoblasts.

Question 13

What are the 2 types of bone tissue?

Answer 13

1. Compact bone - Located on the surface of the bone.

2. Cancellous bone - Located on the interior of the bone.

Question 14

Compact bone is structured to…

Answer 14

Resist stresses.

Question 15

What are lamellae?

Answer 15

Rings of bone wrapped around canal.

Question 16

What are trabeculae within cancellous bone?

Answer 16

A framework of small rings of bone

Question 17

What do the spaces between the trabeculae in cancellous bone contain?

Answer 17

Bone marrow where new blood cells are made.

Question 18

What is myeloid tissue?

Answer 18

Red bone marrow

Question 19

What is yellow bone marrow?

Answer 19

Fatty tissue that no longer produces blood cells.

Question 20

How is flat bone structured?

Answer 20

Cancellous bone surrounded by compact bone.

Question 21

What are the 2 methods of bone formation?

Answer 21

1. Intramembranous ossification,

2. Endochondral ossification.

Question 22

What are the 3 stages of Intramembranous ossification?

Answer 22

1. Mesenchymal cells secrete osteoid. Deposition of calcium salts leads to calcification.
2. Blood vessels grow into area and supply nutrients and oxygen.
3. Initially only cancellous bone is formed but remodelling occurs and compact bone is formed.

Question 23

What happens during Endochondral ossification?

Answer 23

Cells start to become bone rather than cartilage.

Question 24

What is an epiphyseal line?

Answer 24

Where 2 bones meet where there used to be an epiphyseal plate.

Question 25

What are the 3 stages of bone remodelling?

Answer 25

1. Calcium salts are deposited and reabsorbed as required
2. Bone is thickened to increase strength.
3. Old bone is renewed and injured bone is replaced.

Question 26

What symbol is used to indicate the term fracture?

Answer 26

Hash symbol.

Question 27

What are the 2 types of fracture?

Answer 27

1. Compound - Breaks the skin, bone protrudes through skin.

2. Simple - Bone is contained within skin.

Question 28

List 6 classifications of fractures…

Answer 28

1. Greenstick - bends and cracks (only in children)
2. Comminuted - 2 or more broken pieces
3. Linear - Runs down the bone
4. Transverse - Broken straight across the bone.
5. Oblique - Slanted fracture
6. Spiral - Bone has been twisted apart.

Question 29

What are the 4 stages of bone healing?

Answer 29

1. Haematoma formation.
2. Area is invaded be capillaries, fibroblasts, osteoclasts and osteogenic cells and a soft callus forms.
3. Soft callus is hardened by mineral desposition.
4. Remodelling by osteoclasts occurs.

Question 30

How long does it take for a bone to heal?

Answer 30

8 weeks - depending on good blood supply and freedom from infection.

Question 31

List 5 factors that delay bone healing?

Answer 31

1. Deficient blood supply
2. Tissue fragments between bone ends
3. Poor alignment of bone ends
4. Continued mobility of bone ends
5. Infection

Question 32

Functional classification of joints…

Answer 32

1. Synarthrosis - little or no movement
2. Amphiarthrosis - slightly moveable
3. Diarthroses - freely moveable

Question 33

Structural classification of joints…

Answer 33

1. Cartilaginous - bones held together by cartilage
2. Fibrous - Bones held together by collagenous fibres.
3. Synovial - Bones separated by a joint cavity and enclosed in a fibrous capsule.