primitive node(redirected from protochordal knot)
a local thickening of the epiblast at the cephalic end of the primitive streak of the embryo (the node is an embryonic organizer).
a knoblike accumulation of cells at the cephalic end of the primitive streak in the early stages of embryonic development in humans and higher animals. It consists of mesoderm cells that give rise to the notochord, and it corresponds to the dorsal lip of the blastopore in lower animals. Also called Hensen's knot, Hensen's node.
prim·i·tive node(prim'i-tiv nōd)
Hensen,Victor, German anatomist and physiologist, 1835-1924.
Hensen canal - a short membranous tube passing from the lower end of a saccule to the cochlear duct of the membranous labyrinth. Synonym(s): Hensen duct; uniting duct
Hensen cell - one of the supporting cells in the organ of Corti.
Hensen disk - Synonym(s): Hensen line
Hensen duct - Synonym(s): Hensen canal
Hensen knot - a local thickening of the blastoderm at the cephalic end of the primitive streak of the embryo. Synonym(s): Hensen node; primitive node
Hensen line - the paler area in the center of the A band of a striated muscle fiber, comprising the central portion of thick filaments that are not overlapped by thin filaments. Synonym(s): H band; Hensen disk
Hensen node - Synonym(s): Hensen knot
Hensen stripe - a band on the undersurface of the membrana tectoria of the cochlear duct.
Hubrecht,Ambrosius A.W., Dutch zoologist and comparative anatomist, 1853-1915.
Hubrecht protochordal knot - a local thickening of the blastoderm at the cephalic end of the primitive streak of the embryo. Synonym(s): primitive node
first in point of time; existing in a simple or early form; showing little evolution.
longitudinal furrow in the primitive streak of the embryo.
see hensen's node.
enlarged cranial end of the primitive streak.
the thickened median area of the epiblast which sets out the future longitudinal axis of the early embryo.