Human Reproduction

• THIS POWER PONT PRESENTATION HAS BEED ALTERED AND MODIFIED FOR EDUCATIONAL PURPOSES THE ORIGINAL PRESENTATIONS CAN BE FOUND ON THE LINKS AT THE END OF THE PRESENTATION

Battle of the sexes!!!

• Are males and females all that different?

• Well…..• Yes• And• No!

Anatomy

Male Female

Similarities

• 2 pouches• Testicles• Ovaries

• Start out inside body• Testicles “descend” before birth

• Fetus begins with “starter parts” that could develop into either gender.

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)

Male or Female???

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

Anatomy – similaritiesFunction – 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!

Females

• Ovaries• 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)

Internal reproductive:

• Vagina• Cervix• Fallopian tube

(uterian tube/oviducts)• Fimbrae• Ovary• Uterus

- Endometrium- Myometrium- Perimetrium

cervixvagina

fimbriae

uterine tube

ovary

uterus

endometrium

myometrium

perimetrium

Fimbrae & Fallopian Tube

Oogenesis in the Ovary

OogenesisOvary- contains 400,000 oocytes; release

about 500 in a lifetime• Ovary- under influence of FSH. The

follicles mature every 28 days• Primary follicle produces estrogens• And primary oocyte completes its 1st

division produces 2ndary oocyte and polar body

Oogenesis• Aprox 1/2 way through the 28 day cycle the

follicle reaches the mature Vesticular or Graffian follicle stage.

Oogenesis

• Estrogen levels rise and release LH and FSH and triggers ovulation.

Oogenesis• The 2ndary oocyte travels down the uterine

tube to the uterus.• If fertilized by sperm, it will produce a zygote

Ovum in uterine tube

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

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

28-Day Cycle (average)

• Three Stages1. Tear Down2. Rebuild3. Extra nutrients/blood for potential baby

• No Baby?• Back to #1

Chemicals (hormones)

• Regulate events in the body• Estrogen• Progesterone• LH (leuteinizing hormone)• FSH (follicle stimulating hormone)• Many others

Day 1

• First menstrual blood & tissue• No baby = breaks down lining of uterus• 5-7 days of blood/tissue exits body

Pre-Ovulation

~Day 14

• 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

If fertilized…

• Zygote begins to divide as it travels through oviduct

• Implants into lining of uterus

If not fertilized…

• Egg travels through oviduct to uterus• Exits body with blood and tissues during

menstruation

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

Male

• Testes• 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!

Testes

Male Reproductive System

Male Reproductive System

External structure of the penis:

• glans penis

• prepuce (foreskin)

• There is no verifiable health benefit to circumcision.

Circumcision

foreskin glans penis urethral opening

suturesshaft

corona

Semen

• Contains• 300-500 million sperm• Sperm food• pH buffers

• Allows sperm to survive for a couple of days inside female’s body (hostile environment)

What is sperm?

• Then…• Used to think it was a tiny human

inside each cell• Spermists vs. Ovists

Now…

• Contains Several Parts:

• Head• Chemical to dissolve

egg goo• Dad’s genetic

information (DNA)• Mitochondria

• Energy• Tail

• Swimming

Prostate Gland

• Adds non-sperm stuff to semen• pH buffers• Nourishment

• Cancer very common• Slower-growing (usually)• Surgery for removal

Bulbourethral gland

• Adds lubricant to aid travel of semen through the urethra

Conception/Fertilization

Conception/Fertilization

• Ejaculation• Release of 300-500 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

Once egg is located…• Dissolve protective goo surrounding egg• One gets through – enters egg• Instant biochemical change in zygote

• No more sperm allowed in

Zygote begins development

Time Lapse Development

Implants in uterine lining• Endometrium= outer lining of uterus

• Becomes placenta

• Uses mother’s nutrients• Continues development

Fetal Development

• Anmion• 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

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

Ancient beliefs

• Wak Wak tree

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

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

Twins/Multiple Births

• Two types• Monozygotic

• From one egg• Identical

• Dizygotic• From two eggs• Fraternal• Not identical

Identical twins

• One zygote• Splits in 2• No one knows why!• Completely random =

does NOT run in families• Same exact DNA• Nature’s clones

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

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.

REFERENCES

Human reproduction .Accessed from:http://www.iteachbio.com/.../Reproductive%20System/Human%20Reproductio...%E2%80%8E .Accessed:06/03/2014

27 REPRODUCTION.ACCESSED FROM:http://www.wcc.hawaii.edu/.../Marieb%20ZOOL%20142%20%20PPT/027%20...%E2%80%8E

http://www.slideshare.net/promnqobi/human-reproduction-completed