1. Reproductive Organs and Hormones
Unit 2

2. What you should know
The structure and function of reproductive organs and gametes and their role in fertilisation.
Gamete production in the testes. The roles of seminiferous tubules, interstitial cells, testosterone, prostate gland and seminal vesicles.
Gamete production in the ovaries to include maturation of ova and the development of a follicle. Site of fertilisation in the oviduct and zygote formation.

3. Reproductive Organs and Gametes
Prior Knowledge
Reproductive organs produce gametes
Male gamete- sperm
Female gamete- egg/ova
Male reproductive organ- testes
Female reproductive organ-ovary

4. Production of Gametes
A germ line is the sex cells (eggs and sperm) that are used by sexually reproducing organisms to pass on genes from generation to generation.
Gametes are produced by germline cells

5. MALE REPRODUCTIVE SYSTEM
BLADDER
URETER
PUBIC BONE
SEMINAL VESICLE
PROSTATE GLAND
RECTUM
URETHRA
ERECTILE TISSUE
COWPER’S GLAND
VAS DEFERENS
PENIS
EPIDIDYMIS
SCROTUM
TESTIS

6. TESTES
SEMINIFEROUS TUBULE
INTERSTITIAL CELLS

7. TESTES Seminiferous tubules – produce sperm
Interstitial cells– secrete testosterone
Interstitial cells

8. Accessory Glands Seminal vesicles and the prostate gland
Semen consists of 10% sperm and 90% fluid and as sperm pass down the ducts from testis to penis, (accessory) glands add various secretion
The prostate gland and seminal vesicles secrete fluids that maintain the mobility and viability of the sperm. This fluid is called semen
Seminal vesicles secrete a fructose rich liquid, which provides energy for the mobility of the sperm
The liquid also contains hormone like compounds (Prostaglandins) which stimulate contractions of the female reproductive tract
Prostate gland secretes a thin lubricating liquid containing enzymes which regulate the viscosity of semen

9. FEMALE REPRODUCTIVE SYSTEM
OVIDUCT
ENDOMETRIUM
OVARY
UTERUS
CERVIX
VAGINA

10. THE OVARIES
The ovaries contain immature ova in various stages of development
Each ova is surrounded by a follicle that protects the developing ovum and secretes hormones
Mature ova are released into the oviduct where they may be fertilised by sperm to form a zygote

11. GRAAFIAN FOLLICLE

12. Human Ovulation

17. You should know
The structure and function of reproductive organs and gametes and their role in fertilisation.
Gamete production in the testes. The roles of seminiferous tubules, interstitial cells, testosterone, prostate gland and seminal vesicles.
Gamete production in the ovaries to include maturation of ova and the development of a follicle. Site of fertilisation in the oviduct and zygote formation.

18. Hormonal Control

19. What You Should Know
Hormonal onset of puberty. Pituitary gland releases follicle stimulating hormone (FSH), luteinising hormone (LH) or interstitial cell stimulating hormone (ICSH) via the hypothalamus
Hormonal control of sperm production. FSH promotes sperm production and ICSH stimulates the production of testosterone. Testosterone also stimulates sperm production and activates the prostate gland and seminal vesicles. Negative feedback control of testosterone by FSH and ICSH.
Hormonal control of the menstrual cycle. Development of a follicle and the endometrium in the uterus. Roles of FSH, LH, oestrogen and progesterone in the menstrual cycle. Development of a follicle, the corpus luteum and the endometrium. Follicular and luteal phases. Blastocyst implantation. Negative feedback control through pituitary gland, FSH and progesterone, leading to menstruation.

20. Hormones
Hormones are chemical messengers produced by cells that bind to receptors on the plasma membrane of other cells or enter other cells and alter the metabolic function of these cells.
In response to a signal from the brain, hormones are secreted directly into the blood by the glands that produce and store them. These glands make up what is known as the endocrine system
The testes and ovaries, or "gonads", are endocrine glands.
In males, testes produce sperm and secrete the male sex hormone testosterone;
in females, ovaries produce eggs and the female hormone oestrogen.
It is these hormones that determine secondary sex characteristics like muscle mass and facial hair. They also help to orchestrate sperm production, menstruation and pregnancy.

22. Hormonal Onset of Puberty
At puberty the hypothalamus secretes a releaser hormone that targets the pituitary gland
Releaser hormones cause the release of other hormones to start and stop
The pituitary gland is stimulated to release
follicle stimulating hormone (FSH)
Luteinising hormone (LH) in women
Or interstitial cell stimulating hormone (ICSH) in men
These hormones control the onset of puberty

24. Hormonal Control of Sperm Production

25. Male Hormones
FSH (follicles stimulating hormones) promotes spermatogenesis in seminiferous tubules
ICSH (Interstitial cell-stimulating hormone) stimulates interstitial cells to produce male hormones (eg testosterone)
Testosterone also stimulates sperm production and activates the prostate gland and seminal vesicles
FSH and ICSH exhibit negative feedback control on the pituitary gland decreasing the level of testosterone produced by the interstitial cells

26. NEGATIVE FEEDBACK CONTROL
High levels of testosterone have an inhibitory effect on the pituitary gland
Inhibits secretion of FSH and ICSH
Thus, levels of testosterone fall
Inhibitory effect on pituitary ceases
FSH and ICSH secretion increases
Levels of testosterone increase

27. SELF REGULATION OF TESTOSTERONE
PITUITUARY GLAND
Stimulates
Inhibits
Testosterone
FSH
ICSH
SEMINIFEROUS TUBULES
INTERSTITIAL CELLS

28. Hormonal Control of the Menstrual Cycle

29. MENSTRUAL CYCLE Takes on average 28 days
Menstruation is day 1 to 5 of the cycle
Endometrium starts to repair
Ovulation day 14
Endometrium thick and spongy
Menstruation in absence of fertilised egg
Consists of 32 phases-Follicular phase & Luteal phase

31. Follicular Phase FSH Causes development of follicles in ovary
Stimulates secretion of oestrogen by the follicle
oestrogen stimulates proliferation of the endometrium preparing it for implantation and affects the consistency of cervical mucus making it easier for sperm to penetrate

32. Luteal Phase LH
Peak levels of oestrogen stimulate a surge in the secretion of LH which triggers ovulation
Causes Graafian follicle to rupture (ovulation)
Causes development of the corpus luteum from the follicle
Stimulates the corpus luteum to secrete progesterone

33. Progesterone promotes further development and vascularisation of the endometrium preparing it to receive a blastocyst if fertilisation occurs
Ovum dies after 36 hours

34. Negative Feedback Effect of Ovarian Hormones on the Pituitary
High levels of oestrogen and progesterone have an inhibitory effect on the pituitary gland
Decrease the levels of FSH and LH which prevents further follicles from developing
The lack of LH leads to degeneration of the corpus luteum
A drop in progesterone leads to menstruation

35. Menstrual Cycle

36. FERTILISATION

37. FERTILISATION