Cytotrophoblast: Definition from Answers.com

Cytotrophoblast

Primary chorionic villi. Diagrammatic.

Secondary chorionic villi. Diagrammatic.
Gray's	subject #6 47
Carnegie stage	5a
Days	8
MeSH	Trophoblasts

The cytotrophoblast (or layer of Langhans) is the inner layer of the trophoblast, interior to the syncytiotrophoblast in an embryo. It serves to anchor the embryonic chorion to the maternal endometrium.

Cytotrophoblasts are stem cells in the chorionic villi. During differentiation, mononuclear cytotrophoblast fuse together into the multinucleated syncytiotrophoblasts.

The primary villi has only the cytotrophoblast as an axe.

Invading cytotrophoblasts

These cells invade maternal uterine tissues and thus are in direct contact with maternal stroma and immune cells.

Additional images

Section through embryonic area of Vespertilio murinus to show the formation of the amniotic cavity.

External links

Histology at BU 19908loa - "Female Reproductive System: placental villi"
Diagram at McGill

This developmental biology article is a stub. You can help Wikipedia by expanding it.

Developmental biology > Human embryogenesis (development of embryo) and development of fetus

First three
weeks

Week 1

Fertilization · Egg activation · Zygote · Cleavage · Morula · Blastula (Blastomere) · Blastocyst · Inner cell mass

Week 2
(Bilaminar)

Hypoblast · Epiblast

Week 3
(Trilaminar)

Extraembryonic/
uterus

Trophoblast (Cytotrophoblast, Syncytiotrophoblast)

Blastocoele · Yolk sack/exocoelomic cavity · Heuser's membrane · Extraembryonic coelom · Vitelline duct

Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) · Allantois

Placenta · Decidua (Decidual cells) · Chorionic villi/Intervillous space · Gestational sac (Amnion/Amniotic sac/Amniotic cavity, Chorion)

Histogenesis

Programmed cell death (Apoptosis) · Stem cells · Germ line development

Organogenesis

Limb development: Limb bud · Apical ectodermal ridge/AER
other structures: Eye development · Cutaneous structure development · Heart development · Development of the urinary and reproductive organs

(Some dates are approximate—see Carnegie stages and a timeline.)

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