Muscle embryology

Question 1

Draw and label a diagram of developing mesoderm

Answer 1

d

Question 2

Name the 3 types of mesoderm in a developing embryo

Answer 2

Intermediate mesoderm, paraaxial mesoderm and lateral plate mesoderm

Question 3

What does intermediate mesoderm go on to form

Answer 3

geniturinary system

Question 4

What type of muscle does mesoderm form

Answer 4

mast muscles

Question 5

Give an examples of some things formed by ectoderm

Answer 5

pupils and sweat glands

Question 6

What does the paraxial mesoderm form

Answer 6

somites from cells moving at the primitive streak

Question 7

What does the paraxial mesoderm cause

Answer 7

smooth mucle differentation due to the presence of serum reponse factor

Question 8

What 2 layers does the lateral plate mesoderm split into

Answer 8

splanchic and somatic

Question 9

Whatt is formed from the splanchic layer

Answer 9

smooth muscle

Question 10

Define a somite

Answer 10

A block of paraxial mesoderm that gives rise to skeletal muscle

Question 11

What structure influences the formation of somites

Answer 11

the notocord

Question 12

how many pairs of somites are there

Answer 12

34

Question 13

What does the number of pairs determine

Answer 13

the age of the embryo

Question 14

What do somites do once they form

Answer 14

differentiate

Question 15

What do cells in the ventral/media section differentiate into

Answer 15

sclerotome

Question 16

What does sclerotome form

Answer 16

vertebrae and ribs

Question 17

What does cells in the dorsal section form

Answer 17

dermomyotome

Question 18

What does the dermomyotome form

Answer 18

myotome muscles and the dermis of the back

Question 19

How does the notocord regulate somite differentiation

Answer 19

It produces sonic hedgehog and noggin which induce sclerotone formation

Question 20

How does the neural tube and lateral plate regulate somite differentiation

Answer 20

WNT proteins (which are activationg) and BMP proteins (which are inhibitiing) combine to activate MYOD, creating a group of muscle cell precursors that express MYF5

Question 21

How do myoblasts regulate muscle developement

Answer 21

Undergo cell division which i controlled by growth factors

Question 22

What happens when the number of growth factors decrease

Answer 22

1. Fibronectin is secreted
2. Differentiation is mediated by myogenin
3. Myoblasts stop dividing

Question 23

What do myoblasts fuse to form

Answer 23

myotubes

Question 24

How do MYOD and MYF5 regualte muscle development

Answer 24

1. Can convert non muscle cells into muscle cells
2. THey activate muscle specific genes, which enable differntiation of myogenic precursor cellss in dermatome to myoblasts