1. The Reproductive System
A Practical Guide

2. The Reproductive System
Gonads – primary sex organs
Male: testes
Female: ovaries
Gonads produce gametes and secrete hormones
Male gametes: sperm
Female gametes: eggs (ova)
Functions:
Male: produce sperm and testosterone
Female: produce eggs, estrogen and progesterone; nurture the developing embryo; and deliver the newborn baby.

3. Male Reproductive System
External genitalia:
Penis
Scrotum (house testes)
Accessory organs:
Seminal vesicles
Prostate
Bulbourethral gland
Duct system:
Epididymis
Vas deferens
Urethra

4. Male Reproductive System

5. Testes Testes make sperm via meiosis
Produce testosterone – male characteristics
Epididymis – collects mature sperm (mature for 20 days) and eventually propel them through the vas deferens
Vas deferens – tube where sperm travel to the outside of body (peristalsis)
Urethra – urine and sperm leave through

6. Vasectomy
Vasectomy - the vas deferens is cut to prevent sperm leaving (and fertilizing an egg)

7. Accessory Organs Seminal vesicles – produce 60% of semen
Nourish sperm with fructose, Vitamin C
Prostate – secrete milky fluid to activate sperm
Bulbourethral gland – secretes thick, clear mucus
Acts as lubricant
Protects sperm vs. acidic environment found in urethra and vagina

8. External male genitalia
Scrotum – maintains testes at 3°C lower than body
Penis – deliver sperm
Shaft
Erectile tissue fills with blood
Glans penis – enlarged tip
Prepuce – foreskin

9. Sperm
Production of sperm begins at puberty and continues throughout life in the testes
During ejaculation, 2 to 5 ml of semen are released in which there are between million sperm per ml.
Infertility results when there are less than 20 million per ml.

10. Female Reproductive System
Mammaries
Ovaries
Duct System
Fallopian tubes
Uterus
Vagina
External genitalia

11. Female Mammary Glands
Figure 16.13a

12. Female Mammary Glands
Figure 16.13b

13. Mammograms
Figure 16.14

14. Female Internal Genitalia
Ovaries B:
Fallopian tubes – receive oocyte and provide place for fertilization C:
Uterus – receives, retain, and nourishes egg D:
Cervix – Bottom of uterus E:
Vagina – thin walled tube
Birth canal – passageway for delivery of baby and menstrual flow
Receives penis during copulation
Female Internal Genitalia

15. Female External Genitalia
Labia – skin folds
Clitoris – contains erectile tissue
Female correspondent to penis
Greater vestibular gland (i.e. Bartholin’s Gland) – secretes lubricant

16. Ovaries Where eggs are produced through meiosis
Each ovary takes turns releasing one egg per month (twins = two eggs released)
Secrete progesterone and estrogen
Estrogen – secondary sex characteristics in females
Progesterone – regulates menstruation

17. Ovaries Consist of developing follicles Each follicle has:
Oocyte (developing egg)
Follicular cells (surround egg)
Ovulation – when egg is mature the follicle ruptures releasing egg and follicle becomes corpus luteum

18. Oocyte Developing

19. Oogenesis Total supply of eggs are present at birth
Ability to release eggs from puberty  menopause
FSH causes some primary follicles to mature into oocytes every month
LH causes development of secondary follicle
If sperm penetrates oocyte then ovum is produced

20. Fertilization
Sperm must travel to the egg and penetrate to combine the DNA from both parents -- this creates the first cell after fertilization: the Zygote
23 chromosomes from each parent; zygote has a total of 46 chromosomes

21. Fertilization normally occurs in the Fallopian Tubes
Secondary oocyte
Ovulation
Uterus
Endometrium
Uterine tube
Blastocyst cavity
Inner cell mass
Trophoblast
Zygote (fertilized egg)
Early cleavage 4-cell stage
Early blastocyst
Late blastocyst (implanting)
Morula
Ovary
(a)
(b)
(d)
(e)
(c)
The fertilized egg (zygote) implants in the uterus

22. Ova
An egg is usually a few days old before it implants in the uterus.  At this point, it has already divided several times and is called a bastula.

23. Female Cycles
*Interesting fact – humans are one of the few animals that do not have some kind of visible obvious display of fertility.
Evolutionary biologists suggest this trait evolved as a way to keep males interested for more than just the fertile period, increasing the likelihood of male parental care of offspring.

24. Fluctuation of Gonadotropin Levels
Figure 16.12a

25. Fluctuation of Ovarian Hormone Levels
Figure 16.12b

26. Ovarian Cycle
Figure 16.12c

27. Uterine (Menstrual) Cycle
Figure 16.12d

29. How does a woman know she is pregnant?
Missed period
Changes in body, tenderness in breasts, nausea…etc
Pregnancy test – tests urine for hormone levels (hCG – human chorionic gonadotropin) which is produced by the blastocyst 6-12 days after fertilization

30. Clearblue Pregnancy Test

31. Embryo of Approximately 18 Days
Figure 16.16

32. Fetal Development

33. Fetal Development

34. The 7-week Embryo
Figure 16.17

35. Photographs of a Developing Fetus
Figure 16.18a

36. Development of the Human Fetus
Table 16.1 (1 of 2)

37. Development of the Human Fetus
Table 16.1 (2 of 2)

38. Initiation of Labor Figure 16.19, step 1
Baby moves deeper into mother’s birth canal
Figure 16.19, step 1

39. Initiation of Labor Figure 16.19, step 2
Pressoreceptors in cervix of uterus excited
Baby moves deeper into mother’s birth canal
Figure 16.19, step 2

40. Initiation of Labor Figure 16.19, step 3
Afferent impulses to hypothalamus
Pressoreceptors in cervix of uterus excited
Baby moves deeper into mother’s birth canal
Figure 16.19, step 3

41. Initiation of Labor Figure 16.19, step 4
Hypothalamus sends efferent impulses to posterior pituitary, where oxytocin is stored
Afferent impulses to hypothalamus
Pressoreceptors in cervix of uterus excited
Baby moves deeper into mother’s birth canal
Figure 16.19, step 4

42. Initiation of Labor Figure 16.19, step 5
Hypothalamus sends efferent impulses to posterior pituitary, where oxytocin is stored
Posterior pituitary releases oxytocin to blood; oxytocin targets mother’s uterine muscle
Afferent impulses to hypothalamus
Pressoreceptors in cervix of uterus excited
Baby moves deeper into mother’s birth canal
Figure 16.19, step 5

43. Initiation of Labor Figure 16.19, step 6
Hypothalamus sends efferent impulses to posterior pituitary, where oxytocin is stored
Posterior pituitary releases oxytocin to blood; oxytocin targets mother’s uterine muscle
Uterus responds by contracting more vigorously
Afferent impulses to hypothalamus
Pressoreceptors in cervix of uterus excited
Baby moves deeper into mother’s birth canal
Positive feedback mechanism continues to cycle until interrupted by birth of baby
Figure 16.19, step 6

44. Stages of Labor
Figure (1 of 3)

45. Stages of Labor
Figure (2 of 3)

46. Stages of Labor
Figure (3 of 3)

49. Temporary methods of birth control
What if you don’t want to have a baby?
There are lots of options……
Temporary methods of birth control
Condom
Birth control pills
Nuva-ring
Depo-Provera (shot)
IUD (semi-permanent)
Diaphragm

50. More Permanent Options…
Vasectomy
Tubal Ligation

51. What about the morning after pill - also known as Plan B?
Plan B must be taken within 72 hours of unprotected sex, it prevents the egg from releasing or the sperm from fertilizing the egg. It may also prevent implantation of a fertilized egg.
Plan B does NOT work on women who are already pregnant.
It can be bought from pharmacies, though some states have age restrictions.

52. What about abortion?
Regardless of your political views on the subject, abortion is legal in the U.S.
Most procedures must be done early and involve removing the fetus from the uterus.

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