Psychology 1000 Lecture Notes - Lecture 3: Withdrawal Reflex, Doula, Kangaroo Care

• School: Western University
• Department: Psychology
• Course: Psychology 1000
• Professor: Dr.Mike

Document Summary

Changes transforming fertilized egg to newborn human make up prenatal development which takes an average of 38 weeks. Begins with fertilization and lasts about 2 weeks ending when fertilized egg (zygote) implants itself in the wall of the uterus; zygote grows rapidly in these 2 weeks and travels along fallopian tube towards uterus. Occasionally the zygote separates into two different clusters that develop into identical twins, fraternal twins which are more common occur when two eggs are released and fertilized by different sperm cells. Zygote may even divide even more to form triplets. After 4 days the zygote forms a blastocyst consisting of about 100 cells resembling a hollow ball. Implantation: is when the blastocyst burrows into uterine wall and establishes connections with mother"s blood vessels, takes about 1 week to complete and triggers hormonal changes that prevent menstruation. Cells in blastocyst have already started differentiating.