1. Male and Female Reproductive Systems

16. The Menstrual Cycle
The menstrual cycle typically lasts 28 days; approximately 1 month.
One cycle is the amount of time from the beginning of one period to the beginning of the next period.
The beginning of a period is marked by the release of the blood and lining from the inside of the uterus.
This flow of blood typically lasts 3-7 days and is called menstruation.
Menstrual cycle story

17. The Menstrual Cycle
After menstruation, the ovaries release hormones that tell the uterus to grow a new lining and prepare to receive a new egg.
As the uterus prepares a new lining, one of the ovaries releases an egg. This is called ovulation.
Ovulation occurs about halfway through a woman’s cycle.
The egg travels through the Fallopian tube. If it is not fertilized it breaks down and is released with the lining and blood of the uterus.

18. Menstrual Cycle Timeline

19. Menstrual Cycle Timeline

20. The Menstrual Cycle and Fertilization
If the egg is fertilized by a sperm cell, the egg will implant in the lining of the uterus and begin to develop.
Zygote: The first cells of a new organism; the time from fertilization to implantation.
Embryo: The zygote is called an embryo from implantation to 8 weeks.
Fetus: After 8 weeks of development, the embryo is known as a fetus.

21. Sperm Formation MEIOSIS forms sperm in gametes Sperm forms in testes
Scrotum keeps cooler than rest
Semen is sperm plus protecting fluid
Semen leaves testes through the vas deferens (sperm ducts) to the urethra before it exits.
Mrs. Degl

22. Ovum Formation MEIOSIS forms the eggs (ova)
Eggs are formed before birth
1 egg per month is matured and released from ovaries, most of the time
Eggs travel through the fallopian tube where they may become fertilized
Mrs. Degl

23. Fertilization Occurs in upper 1/3 of Fallopian tube
Only 1 sperm can fertilize an egg
Fertilized egg = zygote
An average woman is pregnant (gestational period) for 9 whole months. That is 40 weeks. Babies can survive if they are born earlier, but they may have complications due to being premature.
Mrs. Degl

24. Implantation Fertilized eggs are implanted into thick walls of uterus
Membranes dig into uterus to form placenta
Zygote grows into an embryo
Embryo gets air and nutrients through the umbilical cord
Mom’s uterus grows with the baby
Mrs. Degl

25. 1st Trimester = 1st 12 weeks Heart develops first Neural tube develops
All body systems appear by Week 8 – Now a Fetus
Mrs. Degl

26. 2nd Trimester = up to 24 weeks
Most growth
Looks more like a baby
Some preemies survive at this stage
Mrs. Degl

27. 3rd Trimester = Up to 40 weeks
More growth
Kicking, rolling, stretching
Eyes open – Week 32
Lungs mature
Rotates to head-down
position, unless baby is breech
Mrs. Degl

28. Birth Labor Uterine contractions begin Cervix dilates to 10 cm. Birth
Uterus pushes baby through vaginal canal
Placenta delivered after baby
Cesarean Section (c-section) is a surgery that cuts through the uterus to deliver the baby if it cannot be born vaginally
Mrs. Degl