Female Reproductive System and Pregnancy Mrs. Paparella Spring 2009

1 = vagina 2= uterus 3= ovary 4 = fallopian tube or oviduct

Structure and Functions vagina- receives sperm during mating Cervix- the opening to the uterus Uterus-muscular lining thickens with blood to provide nourishment for embryo; if no embryo gets embedded, the blood is shed during menstruation. The embryo attaches to the wall of the uterus and grows here during pregnancy.

Structure and Function Fallopian tube/oviduct -the sperm must travel to here to fertilize the egg that was produced by the ovary The egg will take about 10 days to travel to the uterus. If a woman has a tubal ligation, her eggs will not be able to reach the uterus. The eggs just get released by the ovary and can’t get fertilized.

Structure and Function Ovary- site of oogenesis (meiosis or meiotic cell division) – follicles produce female gametes and female hormones. The ovaries alternate releasing a mature egg each month (28 days). The egg is released into the oviduct on Day 14 of the menstrual cycle. This is called ovulation. That is the most likely time for fertilization to occur.

Determining Sex of Offspring Female gametes –eggs- only contain the X chromosome. Male gametes- sperm- can have X or Y chromosome. 22 + X = the 23 chromosomes that females contribute. 1n=23 (monoploid #) 22+X or 22+Y = the 23 chromosomes that males contribute. 1n= 23 (monoploid #)

Sperm + Egg uniting is called fertilization. The union of the 2 produces a zygote. The zygote has the 2n number of 46 chromosomes. (the diploid number) 44+ XX = a normal female 44 + XY + a normal male The zygote develops into a blastula- gastrula and then embryo.

The fertilized egg is implanted in the endometrial wall of the uterus.

The Placenta Located inside the uterus Formed from maternal and embryonic tissue Responsible for the exchange of nutrients, respiratory gases (Oxygen and CO2) and wastes. The exchange occurs by diffusion and active transport. There is no direct connection between the circulatory systems of the embryo and mother.

The umbilical cord Connects to the embryo and the placenta Materials are carried by embryonic blood vessels that are located in the umbilical cord.

Picture of IVF embryo - this is a fertilized human egg (also called oocyte) This is seen the morning after an IVF egg retrieval when we check the eggs for signs of fertilization Male and female genetic material (DNA) are contained in the 2 pronuclei seen in the center of the photo

Photo of a high quality day 3 human embryo at the 8-cell stage 6 cells are visible in this plane of focus

Blastocyst picture of a high quality human blastocyst embryo 5 days after in vitro fertilization The clump of cells in the 10 to 12 o'clock area in the picture make up the inner cell mass which become the fetus

Week 9 Arms and legs develop

Week 14 Bone structure developing

Week 31 of pregnancy