Zygote
From Wikipedia, the free encyclopedia
- For other meanings see Zygote (disambiguation).
A zygote (Greek: ζυγωτόν) is a cell that is the result of fertilization. That is, two haploid cells—usually (but not always) an ovum from a female and a sperm cell from a male—merge into a single diploid cell called the zygote (or zygocyte).
Animal zygotes undergo mitotic cell divisions to become an embryo. Other organisms may undergo meiotic cell division at this time (for more information refer to biological life cycles).
Twins and multiple births can be monozygotic (identical) or dizygotic (fraternal), meaning they arise from one or several (strictly, two) fertilisation events.
Zygotes or Zygogene
| Preceded by None |
Stages of human development Zygote |
Succeeded by Embryo |
| Mammalian development of embryo and development of fetus (some dates are approximate - see Carnegie stages) |
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| Week 1: Zygote - Morula - Blastula/Blastomere/Blastosphere - Archenteron/Primitive streak - Blastopore - Allantois - Trophoblast (Cytotrophoblast - Syncytiotrophoblast - Gestational sac)
Week 2: Yolk sac - Vitelline duct - Bilaminar disc Week 3: Hensen's node - Gastrula/Gastrulation - Trilaminar embryo Branchial arch (1st) - Branchial pouch - Meckel's cartilage - Somite/Somitomere - Sclerotome - Myotome - Germ layer (Ectoderm, Endoderm, Mesoderm, Chordamesoderm, Paraxial mesoderm, Intermediate mesoderm, Lateral plate mesoderm, Splanchnopleure, Somatopleure) Histogenesis and Organogenesis Uterine support: Placenta - Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) - Amniotic sac (Amnion, Chorion) |
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