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Human Reproduction.

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Presentation on theme: "Human Reproduction."— Presentation transcript:

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.


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