1. Reproductive Hormones

2. Male Reproductive Hormones
androsterone
testosterone

3. Seminal vesicle
(Rectum)
Vas deferens
Ejaculatory duct
Prostate gland
Bulbourethral gland
(Urinary
bladder)
(Pubic bone)
Erectile
tissue of
penis
Urethra
Glans penis
Prepuce
Epididymis
Testis
Scrotum

4. Erectile tissue
of penis
Prostate gland
(Urinary bladder)
Bulbourethral gland
Vas deferens
Epididymis
Testis
Seminal
vesicle
(behind
bladder)
Urethra
Scrotum
Glans penis

5. Male Reproductive Hormones
both hormones are released from testes

6. Testes Cells
Leydig interstitial cells synthesize hormones (between seminiferous tubules)
Sertoli cells synthesize sperm within seminiferous tubules

7. Testosterone Role
stimulates spermatogenesis (production of mature sperm cells) – life time process
develops male characteristics at puberty

8. Gonadotropic Hormones
gonadotropic hormones regulate gonad development (male and female)
produced in the anterior pituitary; released upon hypothalamus signal
follicle stimulating hormone (FSH)
luteinizing hormone (LH)

9. Male Gonad Development
Hypothalamus secretes gonadotropin-releasing hormone (GnRH)
Anterior pituitary gland releases FSH & LH
FSH stimulates Sertoli cells to form mature sperm
LH stimulates Leydig cells to secrete testosterone

10. Male Gonad Development
Role of testosterone:
promotes Sertoli cell activity - increases sperm cell production
negative feedback on hypothalamus - inhibits the hypothalamus by decreasing the secretion of FSH and LH from the anterior pituitary gland

11. To Much Testosterone Stronger sex drive
may lead to risky behaviours
More impulsive and more aggressive
Mood changes
irritability and depression

12. If testosterone levels get too high
Stimuli from other
areas in the brain
Hypothalamus
GnRH from the
hypothalamus reg-
ulates FSH and LH
release from the
anterior pituitary.
FSH acts on the
Sertoli cells of the
seminiferous
tubules, promoting
spermatogenesis.
LH stimulates the
Leydig cells to make
testosterone, which
in turn stimulates
sperm production.
Anterior
pituitary
Negative
feedback
Leydig cells
make
testosterone
Primary and
secondary sex
characteristics
Sertoli cells
Spermatogenesis
Testis
Figure 46.14
If testosterone levels get too high

13. Female Reproductive System
estrogen
progesterone

14. Female Reproductive System
both produced in the ovaries

15. Vagina
Uterus
Cervix
Ovaries
Oviduct
Uterine wall
Endometrium
Follicles
Corpus luteum

16. Female Reproductive System
comparatively more complicated than male reproductive system
Each ovary contains about 400,000 follicles at puberty
Only about 400 eggs will mature and go through ovulation throughout a woman’s life
Monthly cycle until menopause (~12 x 50 yrs) = cycles
female hormones responsible for oogenesis (development of mature egg cells) and ovulation

17. Ovary Follicle Cells primary oocyte fertilized by sperm
granulosa cells provide nutrients for primary oocyte

18. Female Reproductive System

19. Female Gonad Development
GnRH, FSH and LH involved
Hypothalamus secretes gonadotropin-releasing hormone (GnRH)
Anterior pituitary gland releases FSH & LH
FSH matures follicle
LH causes ovulation and causes corpus luteum maturation

20. Menstrual/Ovarian Cycle

21. Menstrual Cycle menstruation (flow phase) follicular phase
Shedding of the endometrium
Occurs only if there is no ovum fertilization
estrogen and progesterone levels low
follicular phase
Development of follicles
estrogen secretion by granulosa cells
Estrogen signals the endometrium to thicken

22. Menstrual Cycle 3. ovulation ovum leaves ovary
granulosa cells become corpus luteum
corpus luteum begins to secrete progesterone
estrogen levels start to decrease

23. From ovulation to implantation Implantation of blastocyst
Figure 46.15a, b
Ovary
Uterus
Endometrium
From ovulation to implantation
Inner cell mass
Cavity
Blastocyst
Trophoblast
(a)
Implantation of blastocyst
(b)

24. Menstrual Cycle 4. luteal stage
corpus luteum secretes progesterone & small amount of estrogen
progesterone encourages endometrium development for embryo
If no fertilization occurs = no embryo
corpus luteum degenerates after about 10 days and produces a scar (corpus albicans)
Concentrations of estrogen and progesterone decrease
Causing weak uterine contractions (marking the beginning of the flow phase)

27. Can a female get pregnant before she has had her first period?
YES!
By the time she has reached puberty  400,000 follicles (no Corpus Luteum)
Hypothalamus GnRH
AP  FSH, LH
FSH  induces development of follicles
Ovulation occurs before menstruation!

28. What regulates the events of the menstrual/ovarian cycle?
Varying levels of LH and FSH
determined by varying levels of estrogen and progesterone
Many different positive and negative feedback mechanisms involved

29. Follicular Phase Ovulation Luteal Phase 2 3 1 2 3 1
Low level of estrogen inhibits production of LH and FSH (keeping their levels low)
Inhibits AP to prevent ovulation
Ovulation
High estrogen stimulates LH and FSH production (more effect on LH than FSH)
Stimulates AP to cause ovulation
Luteal Phase
High levels of progesterone and estrogen inhibits LH and FSH production
Inhibit AP and Hypothalamus 2 3 1 2 3 1

30. Menopause ovaries lose responsiveness to FSH and LH
usually occurs between ages 46 and 54
most other mammals do not undergo menopause
thought to allow human females to take care of grandchildren rather than continue to reproduce

31. Man-opause? Andropause  male menopause
Decreased levels of testosterone
Sex drive decreased
Increase in memory loss
Breast enlargement
Body composition = more fat, less muscle
More fat = more testosterone is converted to estrogen

32. In class work
Lab Exercise (Hormone Levels During the Menstrual Cycle)
Homework
Section 8.5 – Page 399 #1—5,7-13