1. AP Biology 2005-2006 Human Reproduction & Development

2. AP Biology 2005-2006 Reproductive hormones  Testosterone  from testes  functions  sperm production  Secondary sex characteristics  Estrogen  from ovaries  functions  egg production  prepare uterus for fertilized egg  Secondary sex characteristics LH & FSH testes or ovaries

3. AP Biology 2005-2006 Gametogenesis  Occurs in the gonads (ovaries and testes)  Meiosis that results in the production of gametes (haploid cells) from germ cells (diploid cells)  Spermatogenesis and Oogenesis Slide 2 of 18

4. AP Biology 2005-2006 Spermatogenesis  Occurs in the testes in the seminiferous tubules —results in the production of 4 sperm  Mature in the epididymis and gain mobility  Produced immediately after puberty Slide 6 of 18

5. AP Biology 2005-2006 Spermatogenesis Epididymis Testis Coiled seminiferous tubules Vas deferens Cross-section of seminiferous tubule Spermatozoa Spermatids (haploid) 2° spermatocytes (haploid) 1° spermatocyte (diploid) Germ cell (diploid) MEIOSIS II MEIOSIS I

6. AP Biology 2005-2006 Spermatogenesis  The sperm contains lots of mitochondris (powerhouse of the cell) —why?  The sperm have a long journey  they need a lot of energy (hence the need for lots of mitochondria)

7. AP Biology 2005-2006  Sperm production  over 100 million produced per day!  ~2.5 million released per drop! Male reproductive system

8. AP Biology 2005-2006 Male reproductive system  Testicles  produces sperm and hormones  Scrotum  sac that holds testicles outside of body  Epididymis  where sperm mature  Vas deferens  tubes for sperm to travel from testes to penis  Glands  nutrient rich fluid to feed and protect sperm  buffer to counteract acids in vagina

9. AP Biology 2005-2006 Male reproductive system

10. AP Biology 2005-2006 Pathway of Semen  epididymis (testes)  vas deferens  urethra  A vasectomy is a procedure in which the vas deferens is cut so that the man will no longer be able to father children.

11. AP Biology 2005-2006 Female reproductive system

12. AP Biology 2005-2006 Oogenesis  unequal division of cytoplasm  Allows for more nutrition to be available to the egg in case fertilization occurs. Slide 5 of 18

13. AP Biology 2005-2006 Female reproductive system  Ovaries  produces egg and hormones  Uterus  Nourishes fetus; lining builds up each month  Fallopian tubes  tubes for eggs to travel from ovaries to uterus  Cervix  opening to uterus, dilates 10cm (4 inches) for birthing baby  Vagina  Birth canal for birthing baby

14. AP Biology 2005-2006 Female Reproductive System  ovaries – where oogenesis takes place  oviduct (Fallopian Tube) – where fertilization takes place  uterus – where the embryo grows and develops  vagina – birth canal Slide 12 of 18

15. AP Biology 2005-2006 Female reproductive system

16. AP Biology 2005-2006 Female Reproductive Hormones  LH and FSH act on the ovaries and cause them to produce progesterone and estrogen Slide 13 of 18

17. AP Biology 2005-2006 Female Menstrual Cycle  Each month, a woman’s body prepares for the possible fertilization of an egg  Ovarian cycle = an egg matures and is released  Uterine cycle = the endometrium (lining) of the uterus thickens (becomes ready to have a fertilized egg implant) then breaks down (if no fertilization occurs). Slide 14 of 18

18. AP Biology 2005-2006 Female Menstrual Cycle  ovulation – release of egg from ovary triggered by a surge of LH. Slide 15 of 18

19. AP Biology 2005-2006 Female Menstrual Cycle  Day 1 = first day of a woman’s period  Hormonal control is complicated!  During different times of the cycle, estrogen can either stimulate or inhibit other hormones Slide 17 of 18

20. AP Biology 2005-2006 Female Menstrual Cycle  If fertilization occurs, the embryo secretes HcG which maintains the lining of the uterus  hCG is what is tested for in pregnancy tests  Birth control pills are synthetic progesterone and estrogen that “trick” the body into thinking the woman is pregnant – no ovulation occurs

21. AP Biology 2005-2006 Fertilization

22. AP Biology 2005-2006 Fertilization  Joining of sperm & egg  sperm head enters egg

23. AP Biology 2005-2006 Cleavage  Repeated mitotic divisions of zygote  1st step to becoming multicellular  Unequal divisions establishes body plan  different cells receive different portions of egg cytoplasm & therefore different regulatory signals

24. AP Biology 2005-2006 Cleavage  zygote  morula  blastula  establishes future development

25. AP Biology 2005-2006 Gastrulation  Establish 3 cell layers  ectoderm  outer layers  skin, nails, teeth, nerves  mesoderm  blood, bone & muscle  endoderm  inner lining  digestive system ectoderm mesoderm endoderm

26. AP Biology 2005-2006 Placenta  Materials exchange across membranes

27. AP Biology 2005-2006 Human fetal development 7 weeks4 weeks

28. AP Biology 2005-2006 Human fetal development 10 weeks

29. AP Biology 2005-2006 Human fetal development 12 weeks20 weeks

30. AP Biology 2005-2006 Human fetal development  The fetus just spends much of the 2 nd & 3 rd trimesters just growing …and doing various flip-turns & kicks inside amniotic fluid Week 20

31. AP Biology 2005-2006 Human fetal development  24 weeks (6 months; 2nd trimester) fetus is covered with fine, downy hair called lanugo. Its skin is protected by a waxy material called vernix

32. AP Biology 2005-2006 Human fetal development  30 weeks (7.5 months) umbilical cord

33. AP Biology 2005-2006 Getting crowded in there!!  32 weeks (8 months) The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming

34. AP Biology 2005-2006 Birth Hormone induction positive feedback

35. AP Biology 2005-2006 Intestine Placenta Umbilical cord Wall of uterus Vagina Cervix Birth (36 weeks) Bladder

36. AP Biology 2005-2006 The end of the journey!