1. “Indifferent” ducts of embryo
Y chromosome
present
Y chromosome
absent
Male
Female
uterus
ovary
vagina
penis
testis

2. Biology of gender
Sex chromosomes determine gonadal sex (testis-determining factor)
Phenotypic sex is depends on development of external genitalia w/hormone

3. Differentiation of genitalia depends on whether testosterone is present
At 7 weeks
Undifferentiated
genitalia

4. Intersex individuals experience opposite sex hormones during early development or are insensitive to normal hormones.
Some examples:
Androgen insensitivity
Lack of enzyme for testosterone production
Congenital adrenal hyperplasia (enzyme missing to produce cortisol, aldosterone. Steroids converted to androgens instead.)

5. Male reproductive anatomy

6. Descent of the testes
During fetal development, testes move from abdomen into scrotum
Inguinal area is a common spot for hernias (intestine pokes through abdominal wall)
The scrotum provides a cool area optimal for spermatogenesis

7. 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

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

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

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

11. 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)

13. 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)

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

15. 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

16. 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

18. 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

19. 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

20. 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

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

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

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

24. Low to moderate levels of estrogen

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

26. High levels of estrogen

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

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

29. Luteal phase Corpus luteum secretes progesterone and estrogen corpus

30. 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)

31. Birth control pills, patches, rings
BCP contain estrogen and progestin (or just progestin if nursing or estrogen-sensitive)
They vary in type of progestin and amount of estrogen.
Inhibit LH and FSH, so no ovulation
Thicken cervical mucus
Thicken uterine lining, inhibiting implantation
‘Morning after’ pills contain a much higher dosage

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

34. 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

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

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

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

38. Embryo
Eventually forms
chorion

39. 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.

40. 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

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

42. Question: What are some insufficiencies of the feto-placental unit?
The placenta cannot make estrogen or progesterone on its own
A placenta can be ‘insufficient’ to support fetal growth due to blood flow problems
Hypertension, diabetes, anemia, blood thinners, clotting disorders, smoking. Placental abruption (placenta breaks away)

43. Question: How does the body change during pregnancy?
movie

44. Getting ready for birth....
ACTH and cortisol from the fetus promote prostaglandins, initial contractions occur High levels of estrogen make the uterus more sensitive to oxytocin and initiate gap junctions in myometrium Uterus has mild contractions. Baby’s head is down in pelvis

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

46. Lactation