Neuromuscular embryology

Question 1

What is the mesoderm cell fate determined by

Answer 1

Where in the primitive streak the cells migrate through

Question 2

What is somitogenesis

Answer 2

The formation of somites

Question 3

What are somites derived from

Answer 3

Paraxial mesoderm- separating

Question 4

what direction do somites form

Answer 4

Cranial to caudal

Question 5

What do somites lie lateral to

Answer 5

Neural tube and notochord

Question 6

What do somites differentiate into

Answer 6

Dermatome
Myotome
Sclerotome

Question 7

What does the dermatome form

Answer 7

dermis
muscle stem cells
brown fat cells

Question 8

What does the sclerotome form

Answer 8

Vertebrae and ribs
tendons
blood vessels
meninges

Question 9

which 3 lineages generate the skeleton

Answer 9

• Somites= axial skeleton
• Lateral plate mesoderm= limb skeleton
• Neural crest and head mesoderm= skull and face

Question 10

How do sclerotome cells join to form the vertebrae

Answer 10

Vertebral body develops from caudal part of one sclerotome and cranial part of the next

Question 11

What is vertebrae formed by

Answer 11

Chondrification of sclerotomal mesenchyme

Question 12

What does early fetal cartilaginous vertebrae undergo

Answer 12

Endochondral ossification

Question 13

What are the 3 axes of limb development

Answer 13

• Proximo-distal (shoulder- fingertip )
• Antero-posterior (thumb- little finger)
• Dorso-ventral (knuckle-palm)

Question 14

What are limb buds

Answer 14

Early structures of limbs

Question 15

What causes the formation of limb buds

Answer 15

Activation of mesenchymal cells in the lateral plate mesoderm and cell accumulate under the ectoderm creating a bulge

Question 16

What is the apical ectodermal ridge (AER)

Answer 16

A thickened area of ectoderm at the tip of a limb bud that promotes outgrowth of the limb bud

Question 17

Which structures appear first in the limb bud

Answer 17

Proximal structures

Question 18

What does the proximal-distal development require

Answer 18

Interaction between the AER and progress zone

Question 19

Anterior-posterior axis- What specifies individual digits

Answer 19

Zone of polarising activity and sonic hedgehogs (signally molecule)

Question 20

What is polydactyly caused by

Answer 20

Mutations affecting the zone of polarising activity

Question 21

How do mutations affect the dorso-ventral axis

Answer 21

Dorsal features replaced by ventral features

Question 22

What is the dorso-ventral axis specified by

Answer 22

ectoderm

Question 23

How are digits formed

Answer 23

Initially form as plate, apoptosis needs to occur to seperate digits

Question 24

What does expansion of lateral parts of the neural tube lead to

Answer 24

Formation of thick lateral walks- thin roof/floors

Question 25

What are alar and basal plates

Answer 25

Are where the neural plate differentiates into ventral and dorsal halves

Question 26

What are the alar and basal plates seperated by

Answer 26

Sulcus limitans

Question 27

What do the cells in the alar plate develop into

Answer 27

Sensory neurons

Question 28

What do cells in the basal plate develop into

Answer 28

Motor neurons