PSYCH 250 Lecture Notes - Lecture 3: Umbilical Cord, Prenatal Development, Blastocyst
Document Summary
Ovulation the moment during a woman"s monthly cycle when the ovum (egg) is expelled from the ovary. Brief window for conception: ovum survives 24-48 hours, sperm cells survive 2-5/6 days. Fertilization the union of sperm and ovum; conception: usually occurs in a fallopian tube. Almost all human cells contain 46 chromosomes. Fertilized egg contains a unique set of 46 (23 from each parent) Germinal period (0 to 2 weeks) lasts from fertilization to full implantation (when the cell mass attaches to the uterus wall) Zygote fertilized egg: dividing cells, takes 3 days to go down the fallopian tube to the uterus, when it reaches the uterus, it becomes a blastocyst. Blastocyst hollow, 100 cell ball: forming layers, cell mass moves down uterus and implants in wall. Implantation when the blastocyst becomes imbedded into the uterus wall: only 20-30% of fertilized eggs complete the journey from the fallopian tube to the uterus and implant in the uterine wall.
