Neurulation. Flashcards
What are the 3 major derivatives of the ectoderm?
The neural tube.
The neural crest.
The surface ectoderm.
What does the neural tube form?
The brain and spinal cord.
What does the neural crest form?
The face and teeth.
What does the surface ectoderm form?
The epidermis, hair, nails and the lens and cornea of the eye.
The notochord is found beneath what?
A layer of ectoderm.
Describe the steps primary neuralation?
Formation of the neural plate.
Shaping of the neural plate – thickening and folding of the edges to form the neural folds.
Bending of the neural plate to form the neural groove.
Closure of the neural groove to form the neural tube.
What does primary neurulation form?
The brain.
The anterior spinal cord.
Primary neurulation is of what origin?
Of neuroectoderm origin.
Secondary neurulation forms what?
Sacral and coccygeal segments
Secondary neurulation is of what origin?
mesodermal origin
How do the cells change shape in vertebrate nerulation?
The cell shapes begin to change due to cell elongation and wedging
This is caused by a microfilament ring that causes the base to widen and the top to become more restricted.
What does this cell shape change do?
This forces the sheet of cells that make up the neural plate to curl upwards until they join together at the neural folds. The epithelial ectoderm then covers the folds and keeps them together.
What covers the neural folds and keeps them joined together?
The epithelial ectoderm.
What are the neural crest cells derived from?
The neural folds.
What happens to the neural crest cells once the neural folds seal up?
They migrate throughout the embryo and form many different derivatives.
