1. Reproductive Hormones

2. Reproductive Hormones
Sex hormones are synthesized from cholesterol (a fatty acid) and secreted throughout a person's lifetime at different levels.
Male gonads (testes) produce sperm.
Female gonads (ovaries) produce egg.
Fusion of egg and sperm occur via fertilization to produce a zygote.
The zygote undergoes division to become an embryo, which eventually becomes a fetus.

3. Male Reproductive System

4. Male Reproductive System
Sex hormones: androsterone and testosterone.
Functions of Testosterone:
Testosterone is a male hormone which is produced by the testes.once a boy reaches puberty. It triggers the changes in a boy's body which turn him from a boy to a man.
* Functions of androsterone:
The function of the androsterone receptor protein is to stimulate transcription of certain genes in response to a hormone signal.

5. Male Reproductive System
Hypothalamus and pituitary gland control production of sperm and sex hormones in the testes.
Anterior pituitary produces and stores:
The anterior pituitary produces six major hormones, and the posterior pituitary stores two hormones originating in the hypothalamus. The pituitary's target endocrine glands are the thyroid, adrenal gland, and the gonads. Through these glands it Controls on the development of sexual organs and Physical properties that distinguish men from women sound and body shape and size.

6. Male Reproductive System
At puberty, hypothalamus secretes gonadotropin-releasing hormone (GnRH).
GnRH activates anterior pituitary to release Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH).
LH stimulates the development of the
testes.
FSH activates the testes' sperm-forming cells"

7. Once high levels of testosterone are detected by the hypothalamus, a negative feedback system is activated.
Testosterone inhibits LH production by the pituitary by deactivating the hypothalamus.

8. Male Reproductive System
Negative Feedback for FSH and LH.

9. Female Reproductive System

10. Female Reproductive System
Sex hormones:
Estrogen Progesterone

11. Female Reproductive System
Oogenesis and Ovulation
Ovaries contain fibrous CT and groups of cells called follicles.
Follicles: Primary oocyte (undergoes meiosis to form ovum) and granulosa cells (provides nutrition for oocyte).
Each ovary contains follicles at puberty…many develop during each cycle, but only one reaches maturity.

12. Female Reproductive System

13. Female Reproductive System
FSH & LH released.
FSH stimulates growth of an ovarian body
LH also promotes growth of the corpus luteum (a yellow, progesterone-secreting mass of cells that forms from an ovarian follicle after the release of a mature egg) as the ovary prepares to release the egg into the uterus.
Granulosa cells divide.
Primary oocyte undergoes meiosis I to form a secondary oocyte and polar body.
As granulosa cells grow around the secondary oocyte, a fluid-filled cavity forms (antrum).
Secondary oocyte presses against and eventually ruptures the ovarian wall.

14. Female Reproductive System
Secondary oocyte released from ovary and enters fallopian tubes.
Remaining follicle cells form the corpus luteum.
If pregnancy does not occur within 10 days, the corpus luteum degenerates and leaves a scar (corpus albicans).

15. Female Reproductive System
After ovulation, the secondary oocyte begins meiosis II.
Unequal division occurs to form an egg (ovum) and a polar body.
Overall…one primary oocyte becomes 1 ovum and 3 polar bodies (discarded).

16. Female Reproductive System

17. Female Reproductive System
Menstrual Cycle
28 days.
4 phases:
menstruation
follicular
ovulation
luteal

18. Female Reproductive System
Flow Phase (days 1 to 5)
Shedding of endometrium (menstruation).
Used to mark beginning of menstrual cycle.

19. Female Reproductive System
Follicular Phase (days 6 to 13)
Development of follicles in ovary.
Estrogen secreted.
Triggers thickening of endometrium.

20. Female Reproductive System
Ovulatory Phase (day 14)
Secondary oocyte released from ovary.
Corpus luteum develops.

21. Female Reproductive System
Luteal Phase (days 15 to 28)
Corpus luteum secretes estrogen and progesterone.
Progesterone continues to stimulate growth of endometrium and prepares uterus for an embryo.

22. Female Reproductive System
If fertilization of ovum does not occur, concentration of estrogen and progesterone decreases.
Weak uterine contractions cause endometrium to pull away from uterine wall.
The shedding of the endometrium marks the beginning of the next cycle.

23. Female Reproductive System

24. Female Reproductive System
FSH & LH regulate control of estrogen and progesterone.
Estrogen and progesterone control the FSH & LH.

25. *Males and females both have male and female sex hormones, but in varying levels.

26. عمل الطلاب:
محمد احمد مهاجري
ماجد الاسمري
هاني الغامدي
مشاري الحربي
فيصل المالكي
تحت اشراف: د. عبدالرحمن العجلان