1-Bone Development

Question 1

What is Osteoid?

Answer 1

Type 1 collagen-rich unmineralised organic bone layer

Question 2

Structure of osteoid?

Answer 2

Fibrocartilage embedded in a glycosaminoglycan gel with glycoproteins and support cells

Question 3

The diaphysis refers to which part of bones?

Answer 3

Shaft

Question 4

The epiphysis refers to which part of bones

Answer 4

Ends

Question 5

Cancellous bone is otherwise known as?

Answer 5

Spongy bone

Question 6

Red marrow is found where?

Answer 6

Proximal epiphyses of long bones

Question 7

Articulating surfaces are lined with what type of structure?

Answer 7

Type 2 cartilage

Question 8

What do osteoblasts do?

Answer 8

Secrete organic bone matrix (osteoid) and help process the deposit of mineral salts into the matrix, then convert into osteocytes when finished

Question 9

What do osteocytes do?

Answer 9

Present on the surface or embedded in bone matrix in lacunae. Maintain the organic matrix

Question 10

What do osteoclasts do?

Answer 10

Resorb bone. Have acidophilic cytoplasms, vacuoles and lysosomes

Question 11

Describe the structure of compact bone

Answer 11

Osteon = unit of compact bone. Formed of concentric rings of bone matrix (lamellae) surrounding a central Haversian canal for vessels. Osteocytes sit within gaps called lacunae and communicate via canaliculi

Question 12

How do bisphosphonates work and what are they used to treat?

Answer 12

Bind avidly to hydroxyapetite, inhibing FDPS and GTPases which are essential for osteoclast resorption and survival

Question 13

What are the treatments for osteoporosis?

Answer 13

Exercise, Vitamin D supplements, SERMs (selective oestrogen receptor agonists), bisphosphonates, Cathepsin K inhibitors

Question 14

What are the treatments for Paget’s disease?

Answer 14

Analgesia, physio/hydrotherapy, bisphosphonates, vitamin D and calcium supplements