1. Reproduction in Humans

2. Introduction Male and female reproductive systems
Function together to produce offspring
Female reproductive system nurtures developing offspring
Produce important hormones

3. Male Reproductive system

4. Male reproductive System
Essentially 4 parts:
Testes
Gonads, in scrotum; make gamates and releases sex hormones
Ducts
Epididymis, sperm ducts
Glands
Seminal vesicles, prostate gland
Penis
Urethra and erectile tissue. Arousal leads to filling of the tissue with blood  erection. Enables it to function as a penetrating organ in intercourse

5. Male Reproductive System
Name the structures that are unique to the male reproductive system.

6. Male Reproductive System (cont.)
Sperm cells
Head
Nucleus with 23 chromosomes
Acrosome – enzyme-filled sac
Helps sperm penetrate ovum
Midpiece
Mitochrondria that generate cell’s energy
Tail
Flagellum that propels sperm forward

7. Male Reproductive System: Erection, Orgasm, and Ejaculation
Parasympathetic nervous system stimulates erectile tissue
Become engorged with blood
Orgasm
Sperm cells propelled out of testes into urethra
Secretions from accessory organs also released into urethra
Ejaculation
Semen is forced out of urethra
Sympathetic nerves then stimulate erectile tissue to release blood
Penis returns to flaccid state

8. Female Reproductive system

9. Female reproductive System I
Function is to:
Produce gamates (ova)
Receive the male gamates
Provide a suitable environment for:
fertilisation
Development of fetus
Provide a means of expelling the developed fetus during parturition (birth)

10. Female reproductive System II
Consists of:
Ovaries
Produce Ova, secrete progesterone + oestrogen
Oviducts (Fallopian Tubes)
Uterus
Hollow, pearshaped, muscular. Lining – endometrium – undergoes cyclical changes. Cervix part of uterus that projects thru’ from vagina
Vagina
Muscular tube adapted for reception of the penis and passage of baby out during birth.

11. Female Reproductive System
Name the structures that are unique to the female reproductive system.

12. Internal Female Organs

13. Gamete Production

14. Production of Gametes Production of Gametes – Gametogenesis
Involves special cell division – meiosis
Spermatogenesis
Oogenesis

15. Spermatogenesis 1 Each testis is packed with seminiferous tubules
In these Spermatogenesis takes place
Spermatogonia (germ cells) line the tubules dividing my mitosis to give more spermatogonia (Type A and Type B)

16. Spermatogenesis 2
Type B Spermatogonia will undergo meiosis to eventually form spermatozoa
Type B also known as primary spermatocytes
After the first meiotic division they become secondary spermatocytes

17. Spermatogenesis 3
Secondary spermatocytes rapidly under go the second meiotic division to form spermatids
Spermatids undergo development into spermatozoa

18. Spermatogenesis 4

19. Spermatogenesis 5
During spermatogenesis, cells are supported by Sertoli Cells
Testes also produce testosterone from Leydig cells
Controls rate of sperm production and male characteristics

20. Spermatogenesis 6

21. Spermatogenesis 6 Testes controlled by the anterior pituitary gland
Follicle stimulating hormone (FSH)
Interstitial Cell Stimulating Hormone (ICSH)
ICSH stimulates leydig cells to secrete testosterone  inhibits FSH and ICSH secretion. Negative feedback.

22. Oogenesis 1 The process primordial germ cells (oogonia) become ova
Begins in fetus – oogonia divide by mitosis
By 4 or 5months, some are enlarged – potential to become gametes
Now called primary oocyte

23. Oogenesis 2 Primary oocytes begin first stage of meiosis
By month 7 they are surrounded by follicular cells to form primary follicles
Then Meiosis stops until puberty

24. Oogenesis 3 Once a month some of the primary oocytes continue meiosis
move to surface of ovary
One reaches maturity, others degenerate
First meiotic division finishes – secondary oocyte
Ovulation  follicle ruptures, oocyte released (once released called ovum)
2nd Meiotic division doesn’t occur until the head of a spermatozoan enters the ovum

25. Oogenesis 4

26. Oogenesis 5
After ovulation, the ruptured follicle fills with a blood clot
Cells enlarge
 temporary endocrine structure, the corpus luteum
Grows for 7 – 8 days secreting progesterone and oestrogen
If fertilisation/implantation don’t occur, corpus luteum degenerates after 12 – 14 days.

27. Oogenesis 6

28. Fertilisation & Pregnancy

29. Pregnancy: Fertilisation
Pregnancy – condition of having a developing offspring in the uterus
Fertilisation – process in which a sperm cell unites with an ovum; results in pregnancy
Only one sperm cell penetrates the follicular cells and the zona pellucida that surround the ovum’s cell membrane

30. Acrosome reaction

31. Zygote forms from union of ovum and sperm
After fertilization, ovum releases enzymes that cause the zona pellucida to become impenetrable to other sperm
Zygote forms from union of ovum and sperm
Contains 46 chromosomes

32. Fertilisation & Implantation

33. Pregnancy: The Prenatal Period
Time before birth
Zygote – undergoes rapid mitosis
First week after fertilization
Cleavage – rapid cell division
Morula – ball of cells resulting from cleavage
Travels down fallopian tube to uterus
Becomes blastocyst which implants in endometrial wall
Blastocyst
Some cells (inner cell mass) become embryo
Others, along with cells from uterus, form placenta

34. Fertilisation & Implantation (brief)
Sperm motile – 1mm/min
With muscular movements of uterus get through cervix into oviducts
Fertilisation takes place (diploid)
Fertilised ovum – zygote – begins mitosis
3 days – morula – 16 cells, enters uterus
Fluid enters morula, cells rearrange to become hollow – blastocyst
Blastocyst implants into endometrium – total 10 days

35. Pregnancy: Hormonal Changes
Embryonic cells secrete human chorionic gonadotropin (HCG)
Maintains the corpus luteum
Estrogen and progesterone
Secreted by corpus luteum and placenta
Functions
Stimulate uterine lining to thicken, development of mammary glands, enlargement of female reproductive organs
Inhibit release of FSH and LH from anterior pituitary gland (preventing ovulation) and uterine contractions

36. Pregnancy Testing Kits
These use monoclonal antibodies to test for hormone hCG
hCG produced by placenta
The test relies on the reaction between hCG and antibodies bound to coloured latex beads