Bone Morphology: Clinical examples and experimental evidence

Question 1

Osteoporosis explained

Answer 1

Imbalance in skeletal turnover, bone resorption exceeds bone formation. Leads to calcium loss from bones and reduced mineral density. Increases the risk of fractures.

Question 2

Who is mainly affected by osteoporosis?

Answer 2

Immobolised patients and postmenopausal women due to lower levels of oestrogen.

Question 3

What causes the imbalance?

Answer 3

An inadequate peak bone mass, excessive bone resorption and inadequate formation of new bone. Lack of oestrogen increases bone resorption.

Question 4

Osteogenesis Imperfecta explained

Answer 4

Brittle bone disease, congenital disorder in which the osteoblasts do not produce enough type I collagen.

Question 5

What is rickets disease?

Answer 5

Bone matrix that does not calcify normally and the epiphyseal plate can become distorted by normal strains of body weight, due to calcium deficiency. Deficiency due to insufficient calcium in diet or a failure to produce the steroid pro hormone vitamin D. In children.

Question 6

Achondroplasia explained

Answer 6

Mutation in Fibroblast Growth Factor Receptor (FGF receptor), preventing the formation of collagen. Mutation changes the way the protein interacts with growth factors, preventing the cartilage developing into bone forming short long bones.

Question 7

Experiment: FGF receptor KO mice

Answer 7

FGF receptor gene removed from mice, lead to excessive growth of bones. Showed that FGFR3 reduces the growth of bones.

Question 8

Experiment: How can you prove the growth of a bone?

Answer 8

• antibiotic tetracycline is a fluorescent molecule that binds to new osteoid matter, which can be seen under a UV microscope.
• able to measure the rate of bone growth