1. By Lennart Nilsson, 1965

2. Is Sex necessary for species to be created and maintained?
We do not even in the least know the final cause of sexuality;
Why new beings should be produced by the union of the two sexual elements, instead of by a process of parthenogenesis.
––––– Charles Darwin

4. So why Sex?
Did it occur by accident?
A dice played with universe by God?

6. Bryaninops-yongei-海鞭虾虎鱼

7. Sex is incredibly magic.
The physiology related with sex is complex biological activity

8. Reproductive functions of the male and female
Gonad Gland
Testis
Ovaries
Germ cells
Sperm
Ovum
Hormone-Producing cells
Androgens
(Testosterone)
(Dihydrotestosterone)
(Androstenedione)
Estrogen
Progesterone
Pregnancy
Lactation

9. Reproductive and Hormonal Functions of the Male
I. Spermatogenesis
II. Male Sex Hormones

10. Male Reproductive System
Seminiferous tubule
Male Reproductive System
Interstitial cells
(Leydig cells)

11. Spermatids Spermatozoa (23 chromosomes)
Meiosis
Mitosis

12. Factors Impacting Sperm
Temperature: Cryptorchidism
Disease: Inflammation/Tuberculosis
X-Ray
Smoking & Drinking

13. Functions of Testis
Spermatogenesis --- Seminiferous tubule;
Synthesis and Release of Androgens such as testosterone etc --- Interstitial Cells;
Under influence of FSH and LH released from anterior pituitary gland respectively.

14. Functions of Testosterone
To cause descent of the testes into scrotum;
Effects on development of adult primary and secondary sexual characteristics
(Distribution of body hair; Baldness; Voice; Acne; Protein formation and muscle etc…..)

15. Female Physiology Before Pregnancy and Female Hormones
1. Female Hormonal System?
2. Ovarian Follicle growth?
3. Secretion of estrogen and progesterone?
4. Interplay between Hypothalamic-Pituitary and ovarian Hormones?
5. Relations between Ovarian hormones and menstruation?

16. I. Female Hormone System
Hypothalamus
Gonadotropin-Releasing Hormone (GnRH)
Gonadotropin Hormone:
Follicle-Stimulating Hormone (FSH)
Luteinizing Hormone (LH)
Estrogen/Progesterone; Inhibin

17. Cyclical Secretion of FSH and LH
Female sexual cycle in 28 days
FSH and LH secreted by the anterior pituitary gland in cyclical rhythm regulate the cyclical ovarian changes and subsequent secretion of ovarian hormones.
Importance: surge of LH and FSH?

18. II. Ovarian Follicle growth
Histology of Ovarian Follicle
Ovum
Follicle cells
Granulosa
Thecal cells
Proliferation and Secretion of Hormones are regulated by FSH and LH.

19. 6-12
Lutein cells
Granulosa
& Theca cells
Ovulation

20. III. Sex Hormone Secretion in Ovarian Cycle
Luteal Phase
Follicular Phase
III. Sex Hormone Secretion in Ovarian Cycle
Cell type
Granulosa cells
Lutein cells
Hormone
Estrogen
Estrogen
Progesterone
(Inhibin)
Estrogen
Progesterone

21. Functions of the Ovarian Hormones
Estrogen
Effect on the Uterus and external female sex organs;
Effect on the Fallopian Tubes and Breast;
Effect on the Skeleton;
Effect on Protein Deposition, fat deposition and Body metabolism;
Effect on Hair Distribution and Skin;
Effect on electrolyte Balance;
Negative and Positive feedback effect on Anterior Pituitary Gland;
Progesterone
Effect on the Uterus, Fallopian tubes and Breast;
Effect on the body temperature;
Feedback effect on Anterior Pituitary Gland
Before Ovulation
After Ovulation

22. IV. Interplay between Hypothalamic-Pituitary and ovarian Hormones
GnRH induces Anterior Pituitary Gland to Secret LH and FSH;
LH and FSH regulate the follicle growth and subsequent estrogen and progesterone secretion;
Negative feedback effects of estrogen and progesterone on LH and FSH secretion;
Positive feedback effect of estrogen before ovulation -- LH surge

23. GnRH Estrogen Progesterone Estrogen
Hypothalamus
GnRH
FSH LH
Estrogen
Progesterone
Estrogen

24. Interplay between FSH/LH and Ovarian Hormones
Hypothalamus
④ Estrogen
(High Level)
GnRH ① ⑧
Estrogen
Progesterone
(Inhibin) ⑨
Corpus
Albicans
③ Estrogen
(Low level) ②
FSH、LH
⑥ Ovulation ⑤
LH↑
FSH↑ ⑦
Corpus
Luteum
LH Surge
Interplay between FSH/LH and Ovarian Hormones

25. V. Relations between Ovarian hormones and menstruation
Menstrual phase
Proliferative phase
Secretory phase