Embryology 2.2

Question 1

What induces the mesoderm to start to thicken?

Answer 1

the neural tube sends out signals

Question 2

Describe what happens when the mesoderm becomes no longer a single layer of cells?

Answer 2

forms a block with the notochord and neural tube sitting in the centre
and
divides itself into three parts on either side of the neural tube and the notochord

Question 3

What are the three divisions of the mesoderm called?

Answer 3

paraxial mesoderm (closest to centre)
intermediate plate mesoderm
lateral plate mesoderm

Question 4

What will happen to the lateral mesoderm- almost as soon as it is formed?

Answer 4

the lateral plate mesoderm is gonna divide itself into two layers
- one on side of ectoderm and one on side of the endoderm
- called somatic and splanchnic mesoderm
- space inbetween called intraembryonic coelom

Question 5

What happens to paraxial mesoderm?

Answer 5

somite formation - brick-like structures
35-37 pairs of somites

Question 6

What are somites going to go on and form?

Answer 6

form dermis of your skin, bones and musculature

Question 7

Describe the further development of somites?

Answer 7

each somite will divided into three

Question 8

What are the three structures that are formed from the somite?

Answer 8

dermatome- dermis of skin
myotome- the muscles
sclerotome- the bones

Question 9

Describe how theses structures are going to migrate?

Answer 9

dermatomes- migrate underneath the ectoderm (will form epidermis of skin) to form the dermis of the skin

muscles also migrate to different regions like intercostal muscles in thorax or muscles of upper and lower limbs

sclerotome goes and forms the bone. Encircles neural tube to form the vertebrae

Question 10

What happens to the dermatome as it migrates along the body and how is it innervated?

Answer 10

Ramus going to go along with this dermatome that’s migrating until wherever the dermatome goes and stays.
Spinal nerve is going to innervate it as well.