1. The Reproductive System

2. Male and Female Reproductive Systems
Are functionally different
Female produces 1 gamete per month:
retains and nurtures zygote
Male disseminates large quantities of gametes:
produces 1/2 billion sperm per day

3. Functions To ensure survival of the species
produce egg and sperm cells
transport & sustain these cells
nurture the developing offspring
produce hormones

4. The Male Reproductive System

5. Pathway of Sperm Testes or male gonads:
secrete male sex hormones (androgens)
testosterone
produce male gametes (spermatozoa or sperm)
contribute X and Y chromosomes

6. Pathway of Sperm Epididymis superior to each testis tubular (5-6cm)
takes ~2 weeks for sperm to mature/ travel through

7. Pathway of Sperm Vas deferens: tubes
transport sperm from testes to the ejaculatory ducts
where a vasectomy occurs

8. Pathway of Sperm Ejaculatory duct Urethra passes urine & semen out
entrance way for STDs

9. Accessory Organs Secrete fluids into ejaculatory duct & urethra
Seminal vesicles
secrete alkaline fluid containing fructose, vitamin C, and coagulating enzymes
Prostate gland
produces milky white fluid which activates sperm
Bulbourethral gland
thick clear ejaculate fluid which neutralizes traces of acidic urine in the urethra

11. External Genitalia Scrotum: Penis: surrounds testes
scrotal skin lengthens and shrinks to maintain optimal temperature
Penis:
erectile organ

13. Sperm

15. Spermatogenesis

16. Testosterone Stimulates spermatogenesis Affects CNS functions
libido & related behaviors
Stimulates metabolism
blood cell formation, muscle growth

17. Testosterone Establishes male secondary sex characteristics:
distribution of facial hair
increased muscle mass and body size
characteristic adipose tissue deposits
Maintains accessory glands and organs of male reproductive tract

19. Female Reproductive System

20. Functions Produces sex hormones and functional gametes
Protects and supports developing embryo
Nourishes newborn infant

21. Female Organs Ovaries or female gonads:
release 1 immature gamete (oocyte) per month
produces estrogen & progesterone

22. Female Organs Ovum (egg): female reproductive cell
contributes X chromosome

23. Female Organs
Fallopian tubes:
carry oocytes to uterus

24. Female Organs Uterus: Cervix: “womb”
encloses and supports developing embryo
lining is shed when no fertilized egg is present
Cervix:
lower end of the uterus

25. Female Organs Vagina: connects uterus with exterior
pathway for menstrual flow, birth canal, sperm, & STDs

26. Mammary Glands Modified sweat glands
Ducts and glands do not complete development unless pregnancy occurs

27. Estrogen Stimulates bone and muscle growth
Maintains female secondary sex characteristics:
body hair distribution
adipose tissue deposits

28. Estrogen
Affects central nervous system (CNS) activity (especially in the hypothalamus, where estrogens increase the sexual drive)
Maintains functional accessory reproductive glands and organs
Initiates repair and growth of endometrium

29. Oogenesis Begins before birth Accelerates during puberty
Ceases at menopause

30. Aging - Females Menopause ovulation and menstruation cease
~ ages 45-55
levels of estrogen & progesterone decline
reduction in uterus & breast size
reduction in bone deposits (osteoporosis)

31. Aging - Males Andropause aka male climacteric
occurs over a gradual period of time
testosterone declines
~ age 50-60
sperm production continues

33. Fertilization May occur when: Location: Process: sperm are present
a few days after ovulation
Location:
fallopian tube
Process:
head of sperm enters ovum
nuclei fuse
zygote is formed

34. Fertilization Cleavage: Implantation: initial division of the zygote
continues as the zygote moves towards the uterus
the zygote becomes a blastocyte (hollow ball of cells)
Implantation:
~ 6 days after fertilization
blastocyte burrows into the lining of the uterus

35. Early Zygote Development

36. Pregnancy 9 month gestation period Divided into trimesters
3-month periods
First 8 weeks of pregnancy:
developing human is called an embryo

37. Pregnancy First Trimester: supportive membranes rapid growth
amnion closes & protects the embryo
chorion forms the placenta
structure through which the mother nourishes the embryo

38. Structure of the Placenta

39. Pregnancy First Trimester: Development of Embryo 4th week: 2nd month:
major organs are formed
heart begins to beat
2nd month:
arms and legs take shape
major internal organs are evident

40. Embryo Development

41. Pregnancy First Trimester: Development of Fetus After 1st trimester:
from 8th week - delivery
After 1st trimester:
sex can be distinguished
recognizable body features
organ systems have begun to form

42. Pregnancy Second and Third Trimesters: 3rd trimester: ~9 months:
fetus grows rapidly
organs become functional
3rd trimester:
fetus can exist outside the mother’s body
~9 months:
fetus leaves the mother’s body in a process called labor
usually lasts several hours

43. Events of Human Fetal Development

44. Pregnancy
During childbirth, the fetus exits the mother’s body through the vagina.