NURS 3334 Lecture Notes - Lecture 9: Egg Cell, Gametogenesis, Amnion
Document Summary
Gametogenesis: process which gametes (ovum female, sperm-male) are formed, this occurs during meiosis, each gamete has 23 chromosomes. About twins reproductive treatments: can be dizygotic or monozygotic, so . Sex of the child is determined by the male: 33. 2 in 1000 live births current rate attributed to delayed childbearing and artificial, each twin has its own placenta, chorion and amnion they don"t like to share. May be: two separate ovum, therefore fraternal (not identical, called dichorionic-diamniotic twins same sex or different. Dizygotic twins: increases with age up to 35, fall abruptly, increases with parity, 67% of all twins. Monozygotic twins: same ovum = identical twins, genetically identical, classification depends on time of zygote division past fertilization. Think back to development of chorion, amnion etc: dichorionic-diamniotic twins, monochorionic-diamniotic twins, monochroionic-monoamniotic twins, 33% of all twins, placenta is food, amnion and chorion are house. Embryonic and fetal periods: embryonic developent 4-6 wks.
