Dictionary 5

These are more dictionary words with ‘primitive’…

Primitive Streak: This structure forms during the early stages of avian, reptilian and mammalian embryonic development. This composes the primitive node, primitive pit, and primitive groove.

Primitive Groove: This is a depression made as the cells converge to form the primitive streak.

Primitive Knot: This is also known as Hensen’s node which basically functions as the organizer. These are a knob of cells anterior to the primitive streak.

Primitive Pit: This is a depression directly behind the primitive knot, where the primitive groove ends.

References:

"Primitive Streak." Wikipedia. (2010) Received: Nov. 2010. .

"Primitive Pit." Merriam-Webster Online. (2010) Received: Nov. 2010. .

Gilbert, Scott F. Developmental Biology. Sunderland, MA: Sinauer Associates, 2010. Ch 8, Pg 290