EARLY EMBRYONIC DEVELOPMENT.ppt

8/14/2019 EARLY EMBRYONIC DEVELOPMENT.ppt

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EARLY EMBRYONIC

DEVELOPMENTCM/IKD6 (3 JAM).

Dr. Kamajaya, MSc.,SpAnd.Dept. Biologi

Fak.Kedokteran USU Medan.


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Early Embryonic Development.General Outlines.

1. Gametogenesis.1.1. Gonad development, and the Germ cells.

1.2. Mitotic and Meiotic cells division.

1.3. Spermatogenesis.

1.4. Oogenesis.2. Embryogenesis.

2.1. Fertilization process.

2.2. Cleavage.

2.3. Embryonic germ layers.2.4..Embryonic and Trophoblast

development.

2.5. Organ formation.


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1. Gametogenesis.1.1. Gonad development, and the Germ cells.

Embryological development of the reproductivesystem. Two major stages : 1. Indifferentstage, and 2. Gonad differentiation stage.

1. Indifferent stage. Is common in the both

sex (male and female).From middle of the third week the end of the

sixth week embryonic life.

The period of the primordia genital apparatusconstruction.

No morphological feature which indicates of theembryo as male or female.

Both the gonad and the systems of the canals(Wolffian and Mullerian ducts) which connect withthe urogenital sinus are similar.


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1. Gametogenesis.

1.1. Gonad development, and the Germ cells.

2. Gonad differentiation stage.

Begins at the seventh week :

= Transformation of the undifferentiatedgonad into : testis in a male as an effect ofthe Y-heterochromosome, and Ovarium in afemale because of no Y-heterochromo-some.

= Testicular differention were earliest then

the ovarium differentiation.= In this period, male and female can be de-

termined in reproductive morphologically.


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1. Gametogenesis.1.2. Mitotic and meiotic cell divisions.

1.2.1. Mitotic division.

a. Prophase, b. Metaphase,c. Anaphase, d. Telophase.

1.2.2. Meiotic division.= Meiosis-I :

Leptotene Zigotene Diplotene

Metaphase-I Anaphase-I

Telophase-I.

= Meiosis-II :Prophase-II, Metaphase-II

Anaphase-II Telophase-II.q


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Meiosis.


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mitosis

Germ-cellOogoniumSpermatogonium

SpgOog.

mitosis

meiosis-I

1stSptocyte 1stOocyte

1stOocyte preleptotene

ovulation

2ndSptocyte

Sptid

Spermatozoa

2ndOocyte Ootid

spermiogenesis

Male Female


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2. Embryogenesis.

2.2. Cleavage.


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2. Embryogenesis.2.4. Embryonic and Trophoblast

development.


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Late blastula & Neural fold formation.


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Triploblastic embryo.Organ formation.


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2. Embryogenesis.2.3. Embryonic germ layers.


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Human embryo.


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EARLY EMBRYONIC DEVELOPMENT.ppt

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