L1b - neuralation

Question 1

stages of notochord development from 17 to 18 days after fertilisation

Answer 1

1. prechordal plate formed from proliferation of cells from primitive node
2. notochordal channel
3. notochordal-endodermal fusion
4. definitve notochord

Question 2

how is the neural plate formed and how many days after fertilisation does this occur

Answer 2

ectoderm induced by notochord to thicken and form the plate

- 19 days

Question 3

how is the neural fold and somites formed and how many days after fertilisation does this occur

Answer 3

edges elevates to form the folds
- the midregion becomes depressed and forms grooves - somites

20 days

Question 4

summary of forming neural tube from notochord

Answer 4

1. notochord
2. neural plate
3. neural fold and somites
4. neural tubes
5. neuropores
6. closure of the pores

Question 5

two molecules released for cell differentiation within the neural tube

Answer 5

• Sonic hedgehog (SHH)

- BMPs

Question 6

how is the brain and spinal cord formed

Answer 6

normally BMP4 is induced to have ectodermal form the skin

but Noggin and chordin can inhibit BMP4, forcing the ectodermal cells to form the brain and SC

Question 7

3 types of mesoderm organisation

Answer 7

1. Paraxial mesoderm > forming somites
2. intermediate mesoderm
3. lateral plate mesoderm > parietal + visceral layers

Question 8

what is the process called when the somites first start to differentiate

Answer 8

segmentation

Question 9

what structures does somies develop into

Answer 9

dermis, muscle, tendon, cartilage