decidua & chorionic velli (general embryology)
TRANSCRIPT
Decidua• It is endometrium after implantation which
is sheded after birth of fetus.• Character of endometrium:• Increased secretory function of uterine glands.• Decidual cells are endometrial cells filled with
glycogen.• Arteries become more spiral with arterio-
venous anastomosis.
Dr. Sherif Fahmy
Parts of decidua:• Decidua basalis: It is the part of decidua
between blastocyst and myometrium. It forms the fetal part of placenta.
• Decidua capsularis: It covers the blastocyst except embryonic pole and separates it from uterine cavity.
• Decidua parietalis: It is the rest of endometrium that lines the rest of uterine cavity.
Dr. Sherif Fahmy
Decidua basalisDecidua capsularis
Decidua parietalis
Uterine cavity
Dr.Sherif Fahmy
Dr. Sherif Fahmy
Fate of decidua:• Decidua basalis shares in the
formation of placenta.• Decidua capsularis and parietalis
fuse together and shedded with placenta after delivery.
Dr. Sherif Fahmy
Dr. Sherif Fahmy
Decidua basalis
Decidua parietalis
Decidua capsularis
Uterine cavity
Fused decidua parietalis and capsularis
Decidua basalis
Dr. Sherif Fahmy
3rd Week of PregnancyA- Changes in the chorion.B- Changes in the embryonic disc.
Maturation of blastocyst
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Maturation of blastocystChorionic vesicle Blastocyst
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13th day
Endodermal cells
Secondary yolk sac
Exocoelomic cyst
Somatic mesoderm
Connecting stalk
Somatic mesoderem
Splanchnic mesoderm
1ry chorionic villi
Extra-embryonic coelom Chorionic cavity)
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Cyto-trophoblast
Amniotic cavity
Chorionic Vesicle
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Chorionic Vesicle (at the end of 3rd week)
Changes in the chorionFormation of chorionic velli:1- Primary velli.2- Secondary velli.3- Tertiary velli
A-Chorion frondosum.B-Chorion leave.
Dr. Sherif Fahmy
Dr. Sherif Fahmy
Syncytiotrophoblast
Cytotrophoblast
Primary chorionic velli
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Dr. Sherif Fahmy
Secondary chorionic velli
Syncytiotrophoblas
Cytotrophoblast
Somatic mesoderm
Dr. Sherif Fahmy
Dr. Sherif Fahmy
Fetal blood vessels
Tertiary velli (chorion frondosum)
Tertiary velli (chorion leave)
Cytotrophoblastic shell
Tertiary chorionic velli
Dr. Sherif Fahmy
Dr. Sherif Fahmy
Chorion frondosum
Dr. Sherif Fahmy