Musculoskeletal Development

Question 1

__________: bilateral paired blocks of paraxial mesoderm that form along the head to tail axis of the developing embryo

Answer 1

somites

Question 2

name the 3 critical regions that somites differentiate into

Answer 2

• sclerotomes
• myotomes
• dermatomes

Question 3

interactions between the _______, __________, and ________ are critical for normal development

Answer 3

• notochord
• somites
• neural tube

Question 4

muscle development requires __________

Answer 4

innervation

Question 5

proper joint/bone development requires __________

Answer 5

muscle activity

Question 6

the dermatome will give rise to what?

Answer 6

the dermis of the skin

Question 7

the myotome will give rise to what?

Answer 7

muscles of body wall, neck, and limbs

Question 8

the sclerotome will give rise to what?

Answer 8

• cartilage
• bone
• ligaments/tendons

Question 9

‘sonic hedgehog’ signaling from the notochord is vital to _________ development

Answer 9

sclerotome

Question 10

Wnt from the neural tube is vital to _________ development

Answer 10

myotome

Question 11

3 steps to vertebrae development

Answer 11

• ventral cells surround the notochord/neural tube
• distinct rostral-caudal growth from each somite
• adjacent somites fuse - spinal nerves exit/enter between vertebrae

Question 12

dorsomedial myoblasts form the _________

Answer 12

epimere

Question 13

____ signaling from the ________ promotes myotome differentiation

Answer 13

• Wnt

- dermatome

Question 14

the ___________ develops into the epaxial muscles

Answer 14

epimere

Question 15

dorsolateral myoblasts form the _________

Answer 15

hypomere

Question 16

the ________ develops to form the hypaxial muscles

Answer 16

hypomere

Question 17

What happens to the cervical hypomeres?

Answer 17

they fuse to form ventral neck musculature

Question 18

What happens to hypomeres in the thoracic and abdominal regions?

Answer 18

they retain segmentation and give rise to 3 muscle layers

Question 19

What 3 structures do the hypomeres in the lumbo-caudal region give rise to?

Answer 19

• pelvic diaphragm
• coccygeus
• levator ani

Question 20

mitochondria organize ________ to sarcomeres

Answer 20

parallel

Question 21

muscles are first innervated by _______ nerves and later by ________ nerves, which induce formation of _____________ and __________

Answer 21

• motor
• sensory
• muscle spindles
• intrafusal fibers

Question 22

________ retain some muscular repair capacity which declines with age

Answer 22

satellite cells

Question 23

satellite cells are no longer able to self renew when they lose _______

Answer 23

polarity

Question 24

____________ are the main signal of the apical ectodermal ridge (AER)

Answer 24

FGFs

Question 25

paralogous _________ specify the patterned identity of the limb

Answer 25

Hox genes

Question 26

cranial/caudal axis of a limb is triggered by a small group of cells called _________

Answer 26

ZPA

Question 27

orientation of the limb axis is maintaned by regional signaling/cross talk between the ___________ and ____________

Answer 27

• apical ectodermal ridge

- ZPA

Question 28

dorsally positioned muscles become _______, ventrally positioned muscles become __________

Answer 28

• extensors

- flexors

Question 29

a higher proportion of TBX5 expression will result in more pronounced ________ development

Answer 29

forelimb (bats)

Question 30

a higher proportion of TBX4 expression will result in more pronounced ________ development

Answer 30

hindlimb (kiwi)