1. Human Reproduction

2. Battle of the sexes!!! Are males & females all that different? Well…….…..YES and NO

3. Same embryonic tissues becomes male or female reproductive organs.

4. Male or Female??? DNA determines baby’s gender XX = Female XY = Male All humans are female by default At ~ 7 weeks the baby’s body may be “told” by DNA to become male SRY gene located on the Y chromosome

5. Anatomy - similar Testicles & Ovaries Glands responsible for the production of sex hormones and gametes Start out inside body the Testicles “descend” before birth Vas Deferens & Oviduct Passageway of gametes Penis & Clitoris Contain thousands of nerve ending to aid in sexual stimulation Fetus begins with “starter parts” that could develop into either gender. Same tissue – Same function

6. Physiology – VERY different! Male Uncomplicated Produce sperm 2-4 MILLION every day Female Very Complicated! Born with ~ 400,000 eggs Uses ~500 Ovulation 1 egg “ripens” and is released once a month Careful coordination of hormones & body Support life

7. Males  Produces male sex hormone  Produce 2-4 million sperm every day  Outside body – why?  Sperm like temps 1-2  cooler than body temp  Tube that carries sperm to the seminial vesicle and prostate  Temporary storage of sperm  During copulation, muscle contract to release sperm Testes Vas Deferens Bladder Epididymis Prostate gland Seminal vesicle Urethra Penis  Tube taking both urine and semen outside the body  Bulboureathral gland adds lubricant to aid travel of semen through the ureathra  Erected during copulation for insertion into vagina  Dilation of arterioles causes the erectile tissue of penis become turgid  Semen is squeezed from the penis to the top of vagina

8. Sperm Semen contains 300-500 million sperm – 5% Sperm food (fructose) – 30% Alkaline fluid (pH buffer) – 65% Why so many sperm? Why a pH buffer?

9. What is sperm? Then… Used to think it was a tiny human inside each cell Spermists vs. Ovists Now…Contains several parts Head Contains chemicals to dissolve egg goo Dad’s genetic information – one each of 44 autosomal chromosomes and 1 sex chromosome Mitochondria Energy Contains mitochondrial DNA from mother Flagellum “tail” used for locomotion

10. Females Vagina Cervix Uterus Oviduct Ovary For production of female gametes (ova/eggs) For production of female sex hormones Carries the ovum forward by the beating action of the cilia on its inner surface and the contraction of muscles of oviduct Allows for placenta to attachment During embryo development it protects the embryo and provides a constant environment for the embryo to develop During birth of baby it pushes the baby out by muscular contraction Opening between the uterus and vagina Birth canal

11. Menstrual Cycle 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. Estrogen Ovaries Drop in levels causes shedding of uterine lining Increase in levels causes uterine lining to thicken Progesterone Corpus litheum (ruptured follicle) Drop in levels causes shedding of uterine lining Increase in levels causes uterine lining to thicken LH (leuteinizing hormone) Pituitary gland & hypothalamus Stimulates release of mature egg from ovary FSH (follicle stimulating hormone) Pituitary gland Acts on ovaries to mature the egg HCG (Human Chorionic Gonadotropin) Corpus litheum (ruptured follicle) Produced if fertilization occurs Stimulates continued secretion of progesterone Hormones

13. Spermatogenesis Oogenesis Occurs in the testes Produces 4 hapoid cells Produces 4 viable spermatozoa Motile – swim with tail Production begins at puberty Production continues for entire life Occurs in the ovaries Produces 4 hapoid cells Produces 1 Ovum & 3 polar bodies Nonmotile – moved by currents All eggs present at birth Eggs mature from puberty to menopause

14. Birth Control Birth Control Pills Use hormones to “Trick” body into thinking it’s pregnant No ovulation occurs No ovulation = no egg = no fertilization = no baby! No hormones taken for 7 days = menstruation Barrier Method Male and female condoms prevent sperm from entering the vagina Diaphragm fitted over the cervix & along with use of spermacide to kill sperm No sperms= no fertilization= no baby!

15. Rhythm Method Prevent copulation 7 days before and 7 days after ovulation Uses basal temperature as guide Surgical Sterilization Cut and tie the vas deferens prevents sperm from leaving testes Cut and tie the oviducts prevents egg from leaving ovary and sperm from finding egg Birth Control

16. Sexual Reproduction in Human testis sperms ovary eggs (ova) zygote embryo fetus meiosis fertilization