Embryology

Question 1

What is the process in which the blastula rearranges into 3 germ layers? What are the 3 germ layers.

Answer 1

Process: gastrulation

3 layers: ectoderm, mesoderm, endoderm

Question 2

What two cell types does the inner cell mass give rise to?

Answer 2

Epiblast and hypoblast

Question 3

What molecular signals drive neurulation?

Answer 3

The dorsal lip of the blastopore is called Spemann’s organizer, and releases neural inducers such as the protein Noggin and Chordin.

Question 4

What is nerurlation?

Answer 4

Neurulation is the process in which the neural plate bends up and later fuses to form a hollow tube will eventually differentiate into the brain and spinal cord.

Question 5

‘Animal cap’ (dorsal ectoderm) derived from the blastula gives rise to?

Answer 5

Epidermis

If the ‘Animal Cap’ was derived the gastrula then it would give rise to neural tissue.

Question 6

What allows grafted blastopore cells to induce neural tissue in a region of ectoderm that would normally not give rise to the nervous system

Answer 6

Spemann’s organizer

Question 7

What is the ‘Default Model’?

Answer 7

Neurogenesis is the default option for ectodermal maturation.
If ectoderm is cultured alone, all cells differentiate into neurons.

Question 8

Chordin, Noggin and Follistatin all block the antineuralizing effect of what signaling molecule?

Answer 8

BMP4

Question 9

What happens in lateral inhibition?

Answer 9

More Delta causes more Notch signalling in neighbouring cells. More Notch means less transcription of neural genes, and less Delta.

Question 10

Bone Morphogenetic Proteins (BMPs) are secreted from signal-sending cells, bind to receptors in receiving cells, the receptor phosphorylates a downstream effector and the downstream effector, including transcription factors, changes gene expression, True or False?

Answer 10

True

Question 11

The prosencephalon becomes the telecephalon, which gives rise to the thalamus and hypothalamus, and the diencephalon which gives rise to the cerebral cortex and basal ganglia. True or False?

Answer 11

False!!!
Yes the prosencephalon gives rise to the telecephalon and diencephalon but the telecephalon gives rise to the cerebral cortex and basal ganglia and the diencephalon gives rise to the thalamus and hypothalamus.

Question 12

which primary vesicle gives rise to the metencephalon and myelencephalon?

Answer 12

Rhombencephalon

Question 13

The anterior-posterior axis is created by the differentiation of segments by Hox genes? True or False?

Answer 13

True

Question 14

The notochord releases a signal that causes a divergence in gene expression between dorsal and ventral sides of the neural tube allowing the formation of the roof plate (Dorsal) and floorplate (Ventral) T or F?

Answer 14

True

Question 15

What are organizing centers?

Answer 15

They are signalling nodes (clusters of cells) that secrete morphogens e.g. Spemann’s organizer

Question 16

The anterior-posterior axis is created by the differentiation of segments by Hox genes? True or False?

Answer 16

True

Question 17

What is ‘in-utero electroporation’ and what can it be used for?

Answer 17

Electroporation is a microbiology technique in which an electrical field is applied to cells, in order to increase the permeability of cell membranes, allowing drugs and DNA to be introduced to the cell.
- in-utero electroporation in mice:
pregnant mouse–>injection of DNA into ventricle–> electroporation–>the entire clonal family is then labelled (allowing Transgene expression in vivo)
the method is good for investigating localisation of cells and cell morphology