Development Of The Musculoskeletal System

Question 1

Chondrocytes are coded for by which key gene?

Answer 1

Sox9.

Question 2

Osteoblasts are coded for by which key gene?

Answer 2

Runx2.

Question 3

By which process do all skeletal elements, except cranial vault and majority of facial bones, form?

Answer 3

Endochondral ossification.

Question 4

A mutation in Sox9 causes which disease?

Answer 4

Campomelic dysplasia.

Question 5

A mutation in Runx2 causes which disease?

Answer 5

Cleidocranial dysplasia.

Question 6

Somites are formed from which type of mesoderm?

Answer 6

Paraxial mesoderm.

Question 7

Which 2 signalling pathways are involved in the somite segmentation clock?

Answer 7

Notch and WNT.

Question 8

What kind of polarity do somites have?

Answer 8

Rostrocaudal.

Question 9

What happens during resegmentation of the somites?

Answer 9

Sclerotome will split along the midline and fuse with the adjacent sclerotome.

Question 10

1 somite gives rise to how many vertebrae?

Answer 10

1.

Question 11

Which protein expressed on the somites ensures that the pattern of the ventral roots is established?

Answer 11

Ephrin.

Question 12

How many sets of hox genes are there in vertebrates?

Answer 12

4.

Question 13

Which part of the mesoderm forms the sternum, limbs and pelvic girdle?

Answer 13

Lateral plate mesoderm.

Question 14

Changes in which signalling pathway cause vertebral malformations?

Answer 14

Notch.

Question 15

Name the 5 stages of development of skeletal elements?

Answer 15

1. Condensation.
2. Matrix production.
3. Differentiation (cartilage zones established).
4. Vascularisation and bone collar formation.
5. After birth secondary growth centre formation.

Question 16

What are BMPs required for?

Answer 16

Skeletal and cartilage development.

Question 17

Name a BMP antagonist?

Answer 17

Noggin.

Question 18

What does excess BMP lead to?

Answer 18

Synostosis.

Question 19

What do mutations in Noggin lead to?

Answer 19

Multiple synostosis syndrome.

Question 20

Achondroplasia comes about as a result of mutations in which receptor?

Answer 20

FGF3.

Question 21

What is acromegaly?

Answer 21

Excess growth after epiphyseal plate closure.

Question 22

Which disease is characterised by ossification of muscles provoked by injury?

Answer 22

Fibrodysplasia ossificans progressiva (FOP).

Question 23

How can vascular smooth muscle cells become calcified?

Answer 23

Excess BMPs or decrease in BMP antagonists.

Question 24

Osteoclasts are coded for by which key gene?

Answer 24

RANKL.