formation of germs/ gametes Flashcards Preview

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Flashcards in formation of germs/ gametes Deck (8):
1

From zygote to germ layers

1.

Ectoderm (outside)

Differentiation into:

nervous system (brain, eyes, slain, -> mouth)

2

From zygote to germ layers

2.

Mesoderm (middle)

Differentiation into:

muscle (+heart), blood vessels, skeleton, urinary system

3

From zygote to germ layers

3.

Endoderm

Differentiation into:

digestive system (stomach, intestine, liver...)

4

Cleavage

5

zygote

6

Oogenesis

 

5th month of pregnancy:

Oogenesis (2n) + Mitotic devisions

->

Oocyte 1 (2n)

Birth: FREEZE!

-> Meiosis 1

Adolescence:

Oocyte 1 (1n) + polar body (1n)

OVALUATION

+ meiosis 2

  • Oocyte 2 with ovum (1n)
  • polar body (1n)

 

spermcells arrive

7

Spermatogenesis

5th month of pregnancy:

Spermatogonium (2n) + Mitotic devisions

Birth: -

spermatocyte 1 (2n)

Meiosis 1

2x spermatocyte 2 (1n)

meiosis 2

4x spermids (1n)

-> 4x spermcells (1n)

 

-> go to the ovum (oocyte 2)

8