primitive knot การใช้

Signals for the anterior / posterior axis come from primitive knot.
They are derived from the area of the neural plate anterior to primitive knot.
A primitive node ( or primitive knot ) forms in front of the primitive streak which is the organiser of neurulation.
The primitive knot is situated at the anterior end of the primitive streak and serves as the organizer for gastrulation, determining epiblast cell fate by inducing the differentiation of migrating epiblast cells during gastrulation.
They lack the central-pair microtubules of ordinary motile cilia and so rotate clockwise rather than beat; in the primitive knot at the anterior end of the primitive streak in the embryo, these are angled posteriorly such that they prescribe a D-shape rather than a circle.