Embryology

Question 1

Derivatives of neural crest cells

Answer 1

Ganglia, schwann cells, adrenal medulla, melanocytes

Question 2

Alar plate

Answer 2

sensory

Question 3

Basal plate

Answer 3

motor

Question 4

Mantle zone

Answer 4

grey

Question 5

Marginal zone

Answer 5

white

Question 6

TELENcephalon

Answer 6

cerebrum

Question 7

DIENcephalon

Answer 7

eye cup

thalamus, hypothalamus, epithlamus

Question 8

MESENcephalon

Answer 8

midbrain

Question 9

METENcephalon

Answer 9

pons

cerebellum

Question 10

MYELENcephalon

Answer 10

medulla oblongata

Question 11

Signalling spinal cord

Answer 11

Upregulation FGF
Downregulation BMP 4
expression chordin and noggin

Question 12

Nerual plate signalling

Answer 12

switches from E cadherin to N cadherin

Question 13

When does the neural tube close?

Answer 13

Begins week 4
Anterior D25
Posterior D27

Question 14

When does the eye begin to develop?

Answer 14

end of week 4 - day 22

Question 15

What does the lens form from?

Answer 15

surface ectoderm - placodes

Question 16

What do the layers of the optic cup form?

Answer 16

Outer - pigmented layers of retina
Inner - unpigmented / nervous layer
rim - iris and ciliary body

Question 17

Optic nerve development

Answer 17

In seventh week
inner and outer layers stalk fuse
in 9th week becomes optic nerve

Question 18

Where do the choroid and sclera come from?

Answer 18

mesenchyme surrounding the optic cup

Question 19

Where does the conjunctiva come from?

Answer 19

inner layer of ectoderm

Question 20

Signalling in eye development

Answer 20

PAX6 is the master signalling - expressed in anterior neural plate
SHH responsible for orbit separation - up regulates PAX2 in optic stalks and restricts PAX6 to optic cup and lens

Question 21

Microphtalmia

Answer 21

eyeball too small - genetic condition/ IU infection/ FAS

Question 22

Anophtalmia

Answer 22

absence of eye - genetic/infection

failure of optic vesicle to develop

Question 23

Cyclopia

Answer 23

failure of prosencephalon to divide orbits - mutations in SHH

Question 24

Coloboma iridis

Answer 24

Keyhole defect in iris - failure of choroid fissure to close