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

Dictionary 4

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. .

Dictionary 3

There are a couple of words that I get a little confused because they have the same suffix -‘-lecithal’. This suffix is derived from the Greek word lekithos which means ‘having yolk of an egg’. It would be easy to remember these terms from there etymology.

Isolethical :

• Derived from Greek isos which means EQUAL
• Having the yolk distributed EQUALLY throughout the egg
• In mammals, sea urchins, snails etc.

Mesolethical:

• Derived from Greek mésos which means middle
• Having an intermediate amount of yolk
• In amphibians

Telolethical

• Derived from Greek telos which means NEAR
• Having the yolk NEAR one end of the egg, hence uneven distribution of yolk
• Found in birds, reptiles, and fish.

Centrolethical

• Centro --> CENTER
• Having the yolk near the CENTRE of the egg
• In arthropods

Alethical:

• Relating to an egg with little or NO yolk

References:
Quinion, Michael. "Affixes: -lecithal." Affixes: the Building Blocks of English (2008). Received: Nov. 2010.