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Human Reproduction

Human Reproduction. Battle of the sexes!!!. Are males & females all that different?. Well…….…..YES and NO. Same embryonic tissues becomes male or female reproductive organs. Male or Female???. DNA determines baby’s gender XX = Female XY = Male. All humans are female by default

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Human Reproduction

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  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 Fetus begins with “starter parts” that could develop into either gender. Same tissue – Same function • 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

  6. 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 Physiology – VERY different!

  7. Males Bladder Seminal vesicle Prostate gland Urethra Vas Deferens Penis Epididymis Testes • Produce seminal fluid • Provides a medium for the sperms to swim • To activate and nourish the sperms • SPERM+ SEMINAL FLUID = SEMAN • Prostate cancer – slow growing, surgical removal • 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 • Produces male sex hormone • Produce 2-4 million sperm every day • Outside body – why? • Sperm like temps 1-2 cooler than body temp • Tube taking both urine and semen outside the body • Bulboureathral gland adds lubricant to aid travel of semen through the ureathra • Temporary storage of sperm • During copulation, muscle • contract to release sperm • Tube that carries sperm to the • seminial vesicle and prostate

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

  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 Ovary Oviduct Uterus Cervix Vagina 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 Carries the ovum forward by the beating action of the cilia on its inner surface and the contraction of muscles of oviduct For production of female gametes (ova/eggs) For production of female sex hormones Birth canal Opening between the uterus and vagina

  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. Hormones • 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

  13. Spermatogenesis • 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 • 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 Oogenesis

  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. Birth Control • 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

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

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