1. Human Reproduction

2. Human Reproductive System
Male
Female

3. Male or Female??? DNA determines baby’s gender XX = Female XY = Male
Depends on which egg & sperm get together.
Father determines baby’s gender.

4. Male Female Uncomplicated Produce sperm 2-4 MILLION every day
Very Complicated!
One egg
Once a month
Careful coordination of hormones & body
Timing perfect!

5. Females Ovaries Ovulation 2 pouches
Contain ova
Born with all of her eggs (~ 400,000)
Use up ~500
Won’t run out!
Ovulation
One egg released from ovary to oviduct (fallopian tube)

7. After Ovulation Egg pushed along by cilia
Few days travel time to arrive in uterus
Cervix – Opening between uterus & vagina
Normally tiny
At birth – muscles pull open (dilation) cervix to allow baby to pass through = Labor

8. Menstrual Cycle Complex combination of 10-12 chemicals (hormones)
Usually one egg once a month
All about timing!!!
Uterus must be ready when egg gets there in case it was fertilized
If no fertilization, tear down lining of uterus and rebuild for next month

9. 28-Day Cycle (average) Three Stages No Baby? Tear Down Rebuild
Extra nutrients/blood for potential baby
No Baby?
Back to #1

10. Chemicals (hormones) Regulate events in the body Estrogen Progesterone
Many others

11. Day 1 Pre-Ovulation First menstrual blood & tissue
No baby = breaks down lining of uterus
5-7 days of blood/tissue exits body
Pre-Ovulation

12. ~Day 14 Post-Ovulation Ovulation = Egg released Temp spikes slightly
Most fertile in next few days!
Able to get pregnant
Egg gets fertilized while traveling through oviduct.
Post-Ovulation

13. If fertilized… Zygote begins to divide as it travels through oviduct
Implants into lining of uterus

14. If not fertilized… Egg travels through oviduct to uterus
Exits body with blood and tissues during menstruation

15. Birth Control Pills “Trick” body into thinking it’s pregnant
Extra hormones
No ovulation occurs
No ovulation = no egg = no fertilization = no baby!

16. Male Testes Vas Deferens Produce 2-4 million sperm every day
Outside body – why?
Sperm like temps 1-2 cooler than body temp
Vas Deferens
Tube sperm travel through

17. Semen
Contains
million sperm
Sperm food
pH buffers
Allows sperm to survive for a couple of days inside female’s body

18. Now… Contains Several Parts: Head Mitochondria Tail
Chemical to dissolve egg goo
Dad’s genetic information (DNA)
Mitochondria
Energy
Tail
Swimming

19. Prostate Gland
Adds stuff to semen
pH buffers
Nourishment

20. Conception/Fertilization

21. Conception/Fertilization
Ejaculation
Release of million sperm
Egg needs to be in oviduct
Sperm to egg, not an easy task
Go wrong direction : 2 paths – only 1 leads to an egg
Get attacked by female’s white blood cells
Acidic environment
Current

22. Once egg is located… Dissolve protective goo surrounding egg
One gets through – enters egg
Instant biochemical change in zygote
No more sperm allowed in

23. Gamete – Sex cell; sperm and ova
Zygote – Cell formed after male and female gametes join immediately following fertilization

24. Zygote begins development

25. Implants in uterine lining
Blastocyst implants in outer lining of uterus
Uses mother’s nutrients
Continues development

26. Fetal Development Anmion Amniotic Fluid Membrane surrounding baby
Contains amniotic fluid
Breaks just before birth = “water broke”
Amniotic Fluid
The “water” – surrounding baby
Buoyant cradle for baby
Protection
Free movement

28. Fetal Dev (cont’d) Umbilical Cord Blood vessels from placenta to baby
Mom’s & baby’s blood do not circulate together!
Can have 2 different blood types
Diffusion

30. Birth Labor – muscles used to open cervix Baby flips upside down
Head first!
Feet first = Breech (bad)
Cesarian Section (“C-section”) surgical removal of baby
After baby is born mom delivers placenta (“afterbirth”) that detaches from uterus

31. Breastfeeding Most nutritious option for baby
Milk changes as baby grows
Antibodies from mom create immunity for baby
Studies have shown correlation between breastfeeding and higher intelligence in baby.
Bond w/baby is stronger

32. Twins/Multiple Births
Two types
Monozygotic
From one egg
Identical
Dizygotic
From two eggs
Fraternal
Not identical

33. Identical twins One zygote Splits in 2 No one knows why!
Completely random = does NOT run in families
Same exact DNA
Nature’s clones

34. Fraternal Twins
2 separate eggs get fertilized with 2 different sperm cells
More than one egg got released during ovulation
Siblings
Can be sisters
Brothers
Brother and sister
Tends to run in families

35. Conjoined Twins Used to be called “Siamese” twins
First well known case was in Siam
Identical twins that never completely separated during development
Sometimes can be separated, depending on what is shared.