Bones (2)

Question 1

What type of cells does bones have

Answer 1

cells

extracellular matrix

Question 2

What is bone tissue composed of?

Answer 2

Connective Tissue: supports other tissue/organs, maintain form

2 extracellular components: Organic + Inorganic

Question 3

Describe Organic Extracellular Component

Answer 3

• 33% of bone ECM (extracellular matrix) is organic
• it is made up of Collagen, Ground substances (proteoglycans)
  Function = resists tension

Question 4

Describe Inorganic ECM

Answer 4

67% of bone matrix is inorganic
- made of Hydroxyapatite + other calcium minerals (mineral salts)
the mineral components makes the bone hard and resistant to compression

Question 5

What are the 4 types of cells in the Cellular Component of the bone

Answer 5

• Osteogenic cells
• Osteoblasts
• Osteocytes
• Osteoclasts

Question 6

What do the 4 cells in the bone component maintain

Answer 6

• they maintain bone homeostasis

- it balances the bone destruction and formation that results in the same amount of bone stays the same

Question 7

What are the functions of the 4 cells in the bone component

Answer 7

Osteogenic cells = stem cells that produce osteoblasts

Osteoblasts = MAKERS - produce new bone matrix

Osteocytes: MAINTAINERS + COMMUNICATION - recycle protein and minerals from matrix, they control activity of Osteoblasts/clasts

Osteoclasts = DESTROYERS - remove bone matrix

Question 8

What makes up the structure of the bone

Answer 8

• there are 2 types of cells = Compact + Cancellous

- made of the same things but are STRUCTUALLY DIFFERENT

Question 9

What are the differences between Compact and Cancellous

Answer 9

Compact = Osteon Structure
Cancellous = Trabecular structure

Question 10

What are the 2 subtypes of Compact Bone

Answer 10

1) Macroscopically

2) Microscopically

Question 11

Describe Macroscopically

Answer 11

• the outer surfaces seem dense and impenetrable

- has foramina/holes for blood supply

Question 12

Describe Microscopically

Answer 12

• is made up of circumferential lamellae and units called OSTEONS

Question 13

What are Osteons

Answer 13

Are a longitudinal (lengthwise) unit within Compact Bone

- they provided a pathway for nutrients to get cells in the ECM

Question 14

What is the Osteon composed of?

Answer 14

• A central canal (contains blood vessels and nerves)
• Lamellae
• Lacunae (lakes for Osteocytes)
• Canaliculi (channels for nutrients through ECM)

Question 15

what are the functions and the definition of Lamellae

Answer 15

• is a series of cylinders formed of ECM around the central canal
• they form the shape of Osteon
• Collagen fibres within lamellae resist forces

Question 16

What are Cancellous Bones composed of

Answer 16

• trabeculae (struts of Lamella Bone)
• Marrow fills the cavities between trabeculae
• Osteocytes housed in lacuna in between lamellae/on surface

Question 17

Why are Trabeculae oriented in certain ways?

Answer 17

• Organisation of Trabeculae resists force from multiple directions
• Directs force from body weight in single direction - down the shaft
• spreads force distally`

Question 18

What is the Pelvic Girdle Force DIstribution?

Answer 18

• the Trabeculae channels the weight around the ilia into the femora

Question 19

Describe what Bone Remodeling is

Answer 19

• OSTEOBLASTS add bone matrix in Lamellae to bone surface

- OSTEOCLASTS remove bone from the medullary cavity

Question 20

Describe what Bone Homeostasis is

Answer 20

• is the balance of OSTEOBLASTS and OSTEOCLASTS

- the process is called REMODELLING

Question 21

What happens if their is an imbalance of OB/OC activity

Answer 21

• Osteoporosis and osteopenia is when OSTEOCLASTS outweighs OSTEOBLASTS

Question 22

Describe osteoporosis

Answer 22

Cancellous bone = trabeculae becomes thinner

Compression fractures of vertebrae

Question 23

What can contribute to getting osteoporosis

Answer 23

• Gender
• Lifestyle factors = exercise, nutrition
• start point