1/9
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced |
|---|
No study sessions yet.
identical vs fraternal twins
identical - 1 egg, 1 sperm, splits into 2 embryo ⇒ same DNA
identical twins
fraternal - 2 eggs, 2 sperms, implanted separately w 2 diff placentas
dizygotic twinning
when does fertilization occur
12-24 hours over ovulation
when does cleavage start
starts 30 hours after ferilization
when does the morula form
4-5 days after fertilization
when does the blastocyst form
5-6 days after fertilization
when does implantation occur
7 days after fertilization
dichorionic diamniotic
splits at morula stage; 2 blastocysts, 2 placentas, 2 amnions
monochorionic diamiotic
splits at hatching (blastocyst breaks free from zona pellucida and preps for implantation — cells will move to one side (inner cell mass) and create fluid-filled cavity
results in 1 blastocyst, 2 inner cell mass, 1 placenta, 2 amnions
monochorionic monoamniotic
splits after formation of amniotic sac (7-12 days)
results: 1 blastocysts, 1 placenta, 1 amnion
conjoined twins
splits after gastrulation (~15+ days — already started to develop the germ layers)