1. Sperm production
Epididymis
The cells of Leydig in testes secrete testosterone (T)
T secreted at puberty produces 2o sex characteristics, spermatogenesis, & maintain tracts
Ductus
deferens
Seminiferous
tubules

2. Sperm production Spermatogenesis: spermatogonia (2N) spermatozoa (N)
Epididymis
Spermatogenesis:
spermatogonia (2N)
spermatozoa (N)
Ductus
deferens
Seminiferous
tubules

3. Meiosis Mitosis Sertoli cell Sertoli cell Lumen of seminifeous tubule
Spermatids
Secondary
spermatocyte
Meiosis
Sertoli cell
Primary
spermatocyte
Sertoli cell
Spermatogonium
Mitosis

4. Controlling sperm production
Unlike females, males produce sperm from puberty onward
Spermatogenesis controlled by LH and FSH

5. LH & FSH in males LH acts on Leydig cells for T prod’n
FSH acts on Sertoli cells for sperm prod’n (inhibin provides negative feedback)

7. Causes of infertility? Sperm production, viability influenced by:
Smoking, marijuana use
Alcohol abuse
Anabolic steroids, overly intense exercise, stress
Tight underwear, pants
Environmental pollutants (pesticides, lead, paint, radiation, heavy metals)

8. Sperm storage
Spermatids become motile and are stored in epididymis and ductus deferens

9. Making something to swim in
Seminal vesicles supply fructose, prostaglandins for muscle contraction, & fibrinogen
Prostate gland secretes alkaline fluid and clotting enzymes
Bulbourethral glands add mucus for lubrication
Urinary bladder
Seminal vesicle
Prostate gland
Bulbourethral
gland
Ductus deferens
Testis

10. Signals for erection and ejaculation
Arousal
Pudenal nerves carry signals from penis to lower spinal cord & brain
Spinal reflex and brain send PNS signals to penile arterioles
Arousal causes muscle contractions that incr. physical stimulation – positive feedback
Ejaculation
Dramatic shift to SNS – contractions move semen to urethra and out

12. How does Viagra work?
Viagra blocks PDE5, a enzyme that breaks down a local signal that causes dilation in response to NO
There are many PDE’s – PDE5 is mainly in the penis

13. Female reproductive anatomy
Ovaries produce estrogen, progesterone, and are site of oogenesis
Estrogen: maintenance of the female tracts, 2o sex characteristics, ova maturation and release

14. Oogenesis overview
Oogonia divide mitotically Meiosis I produces a primary oocyte (diploid), surrounded by follicle cells These oocytes develop into secondary oocytes on a cyclical basis

15. Ovarian cycle
Follicular phase - first half of cycle when follicles mature and are ovulated Luteal phase - second half of cycle when uterus is prepared for implantation
Follicular Luteal

16. Looking within the ovary…follicular phase
Primary follicle
Follicle cells
oocyte
FSH and LH levels are increasing

17. Looking within the ovary…follicular phase
Follicle cells secrete estrogen
Dividing
follicular cells
Primary
oocyte
Thecal cells

18. Looking within the ovary…follicular phase
antrum
Antrum collects fluid with estrogen
Estrogen inhibits FSH and LH, so FSH

19. Low to moderate levels of estrogen

20. Late follicular phase
Follicle (thecal) cells
Antrum
High estrogen levels promote LH secretion w/ positive feedback loop
primary oocyte
Follicle (granulosa) cells

21. High levels of estrogen

22. Late follicular phase Mature follicle Oocyte finishes meiosis I
it now is a 2o oocyte
Antrum

23. Pop! Ovulation!
secondary oocyte
Egg is flushed out
Follicle
remains

24. Student questions How do fraternal vs. identical twins occur?
Why are male and female gametes produced in different ways?

25. Luteal phase Corpus luteum secretes progesterone and estrogen corpus

26. Estrogen and progesterone
Estrogen initiates preparation of endo- and myometrium, ‘prime’ uterus for progesterone (follicular phase)
Progesterone endometrium vascularization, glycogen, decrease contractions (luteal phase)
Progesterone inhibits LH and FSH
(this is how birth control pills work)

27. Changes in endometrium
If the corpus luteum degenerates, progesterone drops and menstruation occurs
Degenerating
corpus luteum

28. Student questions Why cramping during periods?
What is the physiology of menstruation?
Why do birth control pills effect periods?
Often estrogen levels are lower w BCP

30. But if there are sperm around…
Fertilization normally occurs within a day of ovulation Contractions of the myometrium help some sperm reach the oviduct
acrosome
in action

31. Embryo forms before reaching the uterus
Cleavage
Blastocyst
Embryo
Fertilization
Trophoblast
Implants the embryo
Ovulation
Implantation

32. Settling into the uterus…
Blastocyst secretes chorionic gonadotropin Endometrium has glycogen, and becomes more vascularized from progesterone 40% of blastocysts never implant

33. Settling into the uterus…
Trophoblast enzymes digest proteins of the endometrium. This carves a hole for implantation.
Endometrium
Endometrium
Trophoblast
Embryo
Embryo

34. Embryo
Eventually forms
chorion

35. Placenta development
Placenta = chorion from embryo and uterine lining from mother. These tissues interlock like ‘fingers’ Projections of chorion have capillaries to form placental villi. They extend into the mother’s blood.

36. Placenta development
Gasses, wastes, nutrients diffuse bw capillaries of mother and fetus Drugs, pollutants, chemicals also diffuse
mother’s blood
Amniotic sac
Placental
villus
Chorion

37. Question:
What does alcohol do to cause fetal alcohol syndrome? How does drug use during pregnancy affect a fetus?

38. Fertilization Delivery Human chorionic gonadotropin (hCG) Estrogen
Progesterone
Fertilization
Delivery

39. Getting ready for birth....
Relaxin from placenta softens the cervix and pelvis Uterus has mild contractions. Baby’s head is down in pelvis High levels of estrogen make the uterus more sensitive to oxytocin. Progesterone levels drop

40. Positive feedback with oxytocin
Stretching the cervix causes more oxytocin to be released Oxytocin induces stronger contractions

41. Lactation