1. Human Reproduction

2. Battle of the sexes!!! Are males and females all that different?
Well…..
Yes
And
No!

3. Anatomy
Male
Female

4. Similarities 2 pouches Start out inside body
Testicles
Ovaries
Start out inside body
Testicles “descend” before birth
Fetus begins with “starter parts” that could develop into either gender.

5. Around 7th Week…
Baby’s body is “told” by DNA to become either male or female.
“Unused” parts disintegrate
“Used” parts continue development
(see overhead)

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

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

8. 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)

10. 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

11. 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

12. 28-Day Cycle (average) Three Stages No Baby? Tear Down Rebuild
Extra nutrients/blood for potential baby
No Baby?
Back to #1

13. Chemicals (hormones) Regulate events in the body Estrogen Progesterone
LH (leuteinizing hormone)
FSH (follicle stimulating hormone)
Many others

14. 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

15. ~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

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

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

19. Birth Control Pills “Trick” body into thinking it’s pregnant
Extra hormones
No ovulation occurs
No ovulation = no egg = no fertilization = no baby!
No hormones taken for 7 days = menstruation

20. Male Testes Vas Deferens Vasectomy 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
Vasectomy
Cut/tie off tube – sperm can’t get out!

21. Semen
Contains
million sperm
Sperm food
pH buffers
Allows sperm to survive for a couple of days inside female’s body (hostile environment)

22. What is sperm?
Then…
Used to think it was a tiny human inside each cell
Spermists vs. Ovists

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

24. Prostate Gland Adds non-sperm stuff to semen Cancer very common
pH buffers
Nourishment
Cancer very common
Slower-growing (usually)
Surgery for removal

25. Bulbourethral gland
Adds lubricant to aid travel of semen through the urethra

26. Conception/Fertilization

27. 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

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

29. Zygote begins development
Time Lapse Development

30. Implants in uterine lining
Endometrium= outer lining of uterus
Becomes placenta
Uses mother’s nutrients
Continues development

31. 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

33. 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

35. Ancient beliefs
Wak Wak tree

36. 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

37. 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

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

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

40. 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

41. 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.