Bones

Question 1

Functions of the bone (6)

Answer 1

Support
Protection
Assistance in movement
Mineral homeostasis
Red blood cell production
Triglyceride storage (in older people)

Question 2

Types of bone (5)

Answer 2

Long
Flat
Short (e.g. wrist)
Sesamoid (e.g. patella)
Irregular (e.g. vertebra)

Question 3

Diaphysis

Answer 3

Shank of the bone

Question 4

Epiphysis

Answer 4

Ends of the bone

Question 5

Articular surfaces

Answer 5

Joint surfaces - continually grow to replenish themselves

Question 6

Periosteum

Answer 6

Surface of the diaphysis which also continually grows - important for healing

Question 7

Haversian canal

Answer 7

Spaces in the bone for blood vessels

Question 8

Osteoblasts

Answer 8

Produce bone material (matrix)

Responsible for cell growth

Question 9

Osteocytes

Answer 9

Are derived from osteoblasts
Maintain matrix
Form network throughout bone structure via canaliculi (long extrusions)
Help channel metabolic substrates and products

Question 10

Osteoclasts

Answer 10

Differentiated macrophage (white blood cell)
Poly-nucleated
Re-absorb bone

Question 11

Osteons

Answer 11

Circular formations made from the three osteogenic stem cells

Question 12

Bone matrix consists of…

Answer 12

Collagen fibres
Ground substance
Inorganic bone salts (largely calcium)

Question 13

Intramembranous ossification

Answer 13

Flat bone formation - strong and light

1. Membranous structures start to contain osteoblasts
2. Bone matrix is laid down
3. Matrix is starved, so caliculi are extended, forming osteocytes
4. Same thing happens in surrounding cells - cells connect
5. Osteoblasts only remain in the periosteum

Question 14

Endochondral ossification

Answer 14

Long bone formation

1. Calcium-based matrix in membrane is devoid of oxygen
2. Osteoblasts form bone cells
3. Primary ossification centre is hollowed out by osteoclasts - stops at epiphysial plate
4. Bone formation occurs in peripheral areas
5. Epiphysis is the secondary ossification centre

Question 15

…% of bone mass is replaced each year

Answer 15

10%

Question 16

How do steroids enhance bone breakdown?

Answer 16

By reducing osteoblast and osteocyte activity, and enhancing osteoclast activity

Question 17

How do female hormones protect bone structure?

Answer 17

Estradiol reduces osteoclast activity and increases osteoblasts

Question 18

Effects of parathyroid hormones (4)

Answer 18

Activates osteoblasts and osteoclasts
Increases calcium and magnesium reabsorption in the nephron
Activates vitamin D to enhance calcium absorption in the nephron
Calcitonin reduces calcium levels in the blood

Question 19

Types of joint (5)

Answer 19

Ball-and-socket (shoulder)
Ellipsoid (wrist)
Saddle (between wrist and fingers)
Hinge (elbow)
Pivot (atlas and axis)

Question 20

Synovial fluid

Answer 20

Surrounds joints in a capsule, acting as a shock absorber and a lubricant

Question 21

Ligaments

Answer 21

Hold bones in place - very tough fibrous tissues