Embryology 4

Question 1

The CNS

Answer 1

Derives from the ectoderm

Question 2

CNS formation begins when

Answer 2

The ectoderm along the dorsal surface folds inwards, driven by local cell shape changes along the three stripes

Question 3

In CNS formation rectangular cells

Answer 3

Change shape to become wedge-shaped to cause the the tissue to fold inwards

Question 4

Spina bifida

Answer 4

Occurs when the ectoderm doesn’t form below the head

Easily treated in most cases

Can be caused by a lack of folic acid in the diet

Question 5

Anencephaly

Answer 5

Occurs when the ectoderm doesn’t form at the head

The inside of the brain is open to back of head - brain growth is missing

Incompatible with post natal life

Question 6

Fetus in fetu

Answer 6

Fetus growing in neural tube if something gets trapped when neural tube is closing

Question 7

Segmentation is first seen

Answer 7

When the mesoderm each side of the midline divides itself into somites

Question 8

Somites

Answer 8

Precursors of vertebrae, skeletal muscle and skin

Question 9

Neural crest cells

Answer 9

Only occur in vertebrates -> they can move and migrate along pathways

Question 10

Face is largely derived from

Answer 10

where neural crest cells meet

Question 11

Cleft palatte

Answer 11

When three palettes do not join up - resulting in no separation between the oral and nasal cavity

Very easily treated

Question 12

Ventral abdominal cavity not sealing up

Answer 12

results in intestine and other abdominal organs spilling out

Very common and easily treated