Gastrulation, Neurulation & Ectoderm Derivatives

30 fill-in-the-blank flashcards covering key concepts from gastrulation to cranial placode development.

During __, profound cell movements convert a sheet of cells into a multilayered embryo establishing the three germ layers.

gastrulation

The three embryonic germ layers are __, __, and __.

ectoderm; mesoderm; endoderm

Somatic cells are derived entirely from the three __.

embryonic germ layers

The primitive streak first forms in the __ layer of the bilaminar disc.

epiblast

The first cells passing through the primitive streak displace the hypoblast to form the definitive __.

endoderm

Epiblast cells that remain on the surface will become the embryonic __.

ectoderm

The oropharyngeal membrane breaks down to form the __ (future mouth opening).

stomodeum

Failure to close the anterior part of the neural tube results in __.

anencephaly

Failure of neural tube closure in the caudal region causes __.

spina bifida

BMP4 signaling promotes __ fate in the ectoderm, whereas its inhibition promotes neural fate.

epidermal

Noggin, Chordin, and Follistatin are secreted antagonists of __ signaling.

BMP4

Inhibition of BMP4 signaling induces neural tissue of __ (forebrain) character.

anterior

Posteriorization of the neural plate is driven by signals such as FGF, WNT, and __.

Retinoic Acid

__ is the process by which the neural plate folds into the neural tube.

Neurulation

Neurulation segregates ectoderm into the neural tube, neural crest, and __.

epidermis

Neural tube closure is initiated at the future __ region and zips up in both directions.

midbrain

Graded concentrations of Sonic hedgehog secreted by the notochord and __ plate pattern the ventral spinal cord.

floor

Neural crest cells undergo an epithelial-to-__ transition before migrating.

mesenchymal

The cardiac neural crest contributes to the septum separating the aorta from the __ artery.

pulmonary

Absence of enteric neurons in the colon due to defective neural crest development is called __ disease.

Hirschsprung’s

Mutations in the TCOF1 gene cause __ dysostosis (Treacher Collins syndrome).

mandibulofacial

Cranial placodes are thickenings of the cephalic __ ectoderm.

embryonic

The lens placode gives rise to the __ of the eye.

lens

The otic placode forms the __ ear responsible for hearing and balance.

inner

Cranial placodes contribute to the __ gland (adenohypophysis).

anterior pituitary

Vagal and sacral neural crest populations form the __ nervous system of the gut.

enteric

Trunk neural crest derivatives include melanocytes, dorsal root ganglia, sympathetic ganglia, and the __ medulla.

adrenal

The __ membrane at the caudal end breaks down to become the anal opening.

cloacal

The primitive node acts as the organizer and is located at the anterior end of the primitive __.

streak