Reproduction

1. Reproduction

2. I. Background • Asexual - fission - budding - gemmules - fragmentation/regeneration

3. Background cont’d B. Some animals reproduce sexually & asexually 1. Daphnia – each female produces 2 types of eggs: - one is fertilized - sexual - one develops without fertilization parthenogenesis - asexual

4. Background cont’d 2. Some lizards use parthenogenesis only - no males - pg. 999

6. Background cont’d C. Sexual 1. Hermaphrodites 2. Sequential hermaphrodites - reverse its sex * protandrous – 1st male * protogynous – 1st female ie. Wrasses reef fish – large females become males

7. Background cont’d 3. External fertilization 4. Internal fertilization

12. II. Male Anatomypg. 919 A. Testes contain: - seminiferous tubules – coiled tubes produce sperm - Leydig cells – scattered b/w tubules – produce androgens (male hormones)

13. Male Anatomy cont’d B. Scrotum - fold of body wall keeps testes outside of body cavity - 2ºC below abdominal cavity - develop in abdomen & descend just before birth (some mammals don’t descend like whales, some are drawn back in b/w breeding seasons)

14. Male Anatomy cont’d C.Epididymis - matures sperm (become mobile) & stores sperm D. Vas Deferens - during ejaculation (expelling of sperm) sperm go here from epididymis E. Ejaculatory duct – short tube from vas deferens to urethra

15. F. Accessory Organs • Add “stuff” to sperm • Seminal vesicles - adds alkaline fluid w/fructose – Why? neutralize female env. & energy • Prostate - contains alkaline fluid & enzymes – Why? neutralize & anticoagulants

16. Accessory Organs cont’d • Bulbourethral gland - Also called Cowper's gland - before ejaculation – secretes clear mucus to neutralize urethra from acid urine

17. Male Anatomy cont’d G. Penis - contains erectile tissue – causes blood to flow in arteries & seal off veins - sperm enters female - average ejaculation contains: 2-5 ml of semen (50 – 130 mil. sperm & all fluids)

18. Male Anatomy cont’d - alkaline semen allows sperm to survive acid vagina - at first semen is coagulated to help move sperm along – then the anticoagulants liquefy the solution so sperm can swim

24. III. Female Anatomy • Ovaries - in abdomen attached to uterus by mesentery & ligament - contains follicle that consists of one egg surrounded by cells for nourishment & protection follicle cells produce hormones

25. Female Anatomy cont’d B. Oviduct – Fallopian tubes - lined w/cilia to draw egg in - fertilization occurs here - egg is sent to uterus C. Uterus - thick, muscular organ – lining called endometrium - contains lots of blood vessels

26. Female Anatomy cont’d D. Cervix - neck of uterus - opens into vagina E. Vagina - thin walled, birth canal - sperm deposited here

28. IV. Gamete Formation • Spermatogenesis - begins at puberty & continues until death - continuous process – sperm not ejaculated is absorbed by body - fig. 46.12

31. Gamete Formation cont’d B. Oogenesis - cytokinesis is unequal – one cell gets more cytoplasm & becomes the egg others are polar bodies & degenerate - stops at menopause ~ age 46 –54 - has resting periods - spermatogenesis does not

33. Male Hormones

34. IV. Male Hormones • Called androgens B. make embryo male C. surge about age 10 D. testosterone - main androgen - causes: secondary sex characteristics - spermatogenesis

35. Male Hormones cont’d E. GnRH - gonadotropin releasing hormone - made in hypothalamus - stimulates pituitary

36. Male Hormones cont’d F. LH - leutenizing hormone - made in pituitary - stimulates production of testosterone & other androgens in testes that are responsible for secondary sex char. & spermatogenesis indirectly

37. Male Hormones cont’d G. FSH - from pituitary - stimulates sperm production H. Negative feedback fig. 46.13 - increased testosterone inhibits LH

38. V. Female Cycles • 2 cycles occur at once 1. Menstrual cycle – prepares uterus 2. Ovarian cycle – prepares egg

39. Female Cycles cont’d B. Menstrual cycle - describes uterine changes over average of 28 days - 3 phases 1. Menstrual flow phase – shedding of uterine lining ~ 1st week

40. Female Cycles cont’d 2. Proliferation phase – regeneration & thickening of endometrium ~ 1-2 weeks 3. Secretory phase – continued thickening ~ 2 weeks If no implantation of embryo a new menstrual flow phase begins

41. Female Cycles cont’d C. Ovarian cycle - parallels menstrual cycle - 3 phases

42. Female Cycles cont’d 1. Follicular phase ~ 1-14 days - many follicles begin to grow - one continues – others degenerate - fluid filled cavity develops in maturing follicle & bulges on surface of ovary - phase ends w/ovulation

43. Female Cycles cont’d 2. Ovulation - rupturing of follicle & ovary wall thus releasing the egg - ~ days 12-14

44. Female Cycles cont’d 3. Luteal phase - follicle becomes corpus luteum - corpus luteum is endocrine tissue which secretes hormones & disintegrates at end of phase - ~ day 15-28

46. Female Hormonal Controls • Know chart pg. 1011 fig. 46.14 for continuous cycle – no fertilization

50. Female Hormonal Controls cont’d • FSH – stimulates follicle • LH – causes ovulation • Estrogen – causes LH surge and build up of endometrium • Progesterone – maintains uterine lining