Hypoblast
Section through the embryo. (Hypoblast visible but not labeled.)
"D" points to the hypoblast.
Days	8
Precursor	inner cell mass
Gives rise to	endoderm

The hypoblast is a tissue type that forms from the inner cell mass.^[1] It lies beneath the epiblast and consists of small cuboidal cells.^[2]

Extraembryonic endoderm (including Yolk sac) is derived from hypoblast.

[edit] References

1. ^ UNSW Embryology- Glossary H
2. ^ Moore, K. L., and Persaud, T. V. N. (2003). The Developing Human: Clinically Oriented Embryology. 7th Ed. Philadelphia: Elsevier. ISBN 0-7216-9412-8.

[edit] External links

• http://www.embryology.ch/allemand/iperiodembry/carnegie02.html
• http://www.med.umich.edu/lrc/coursepages/M1/embryology/embryo/04secondweek.htm
• http://isc.temple.edu/marino/embryology/EMBII97/sld005.htm

v • d • e 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) Germ layers Archenteron/Primitive streak (Primitive pit, Primitive knot/Blastopore, Primitive groove) · Gastrula/Gastrulation · Regional specification Ectoderm Surface ectoderm · Neuroectoderm · Somatopleure · Neurulation · Neural crest Endoderm Splanchnopleure Mesoderm Chorda- · Paraxial (Somite/Somitomere/Sclerotome/Myotome/Dermatome) · Intermediate · Lateral plate (Intraembryonic coelom, Splanchnopleure/Somatopleure) 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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