Growth cone: This is the specialized end of the growing axon that generates the motive force for elongation.
Neurotrophins: This originates from the Greek word trophikos which means ‘nourish’. These neurotrophins provide factors which keep the neuron alive and for growth. These factors are usually growth factors.
Netrins: A family of diffusible molecules that act as attractive or repulsive cues to guide growing axons.
"Construction of Neural Circuits." Neuroscience. 2008. Web. Dec. 2010.
Germinal neuroepithelium: This is what the original neural tube was composed of. It is a single layer of rapidly dividing neural stem cells. The nuclei of these cells are at different heights, therefore giving the appearance of several cell layers – however is only one. Nuclei move within the cells as they go through the cell cycle. When a neuroepithelial cells divides vertically and not horizontally – this is called the neuron’s birthday. The cells which are located superficially are 'born' later than those adjacent to the lumen
Neurons have birthdays too….interesting…
Gilbert, Scott F. Developmental Biology. Sunderland, MA: Sinauer Associates, 2010. Ch 9, Pg 348
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
Archenteron:
During gastrulation of the developing embryo, the archenteron is formed and is known as the primitive gut. In amphibians and fish, the indentation created is called the dorsal blastopore. In birds and mammals it is known as the primitive streak.
The invagination occurs towards the blastocoel hence the archenteron displaces the blastocoel.
Removal of the the deep Involuting marginal zone (IMZ) cells would stops the formation of the archenteron.
References:
"Archenteron." Wikipedia, the Free Encyclopedia. 2010. Web. Nov. 2010.
