The male and female reproductive systems work together to produce offspring. The male system produces sperm which combine with eggs from the female system. A complex interplay of hormones regulates the production of gametes and preparation for pregnancy in both sexes. Fertilization occurs when sperm penetrates an egg, beginning the process of embryonic development and eventual birth.

1. Human Reproduction

2. Review
Both males and females produce
specialized sex cells called “gametes.”
Each gamete contains ½ of the genetic
information to form a new individual.
The role of the male reproductive
system is to produce sperm and deliver
them to the female gamete, the egg.

3. The Male Reproductive System
A sexually mature human male,
produces millions of sperm cells
each day.
Sperm are produced in the testes
by meiosis (spermatogenesis).
Review (meiosis)

4. Structure of Sperm
 Tail- used for locomotion.
 Midsection- contains mitochondria. Why?
 Head- holds chromosomes and digestive enzymes which
allow sperm to penetrate into the egg.

5. Male Testicle- Produces fluid that
nourishes sperm

6. The “Pathway” of Sperm
Seminal Vesicle Prostate Gland
Penis
Urethra
Testes
Bulbourethral Vas Epididymis
Gland Deferens

7. The “Pathway” of Sperm
In order for fertilization to occur, sperm must be
released (ejaculated) from the penis.
During ejaculation:
1.) Muscles in vas deferens push sperm toward urethra.
2.) Tube to bladder is blocked off by a valve.
3.) Glands add fluid to sperm.
- Seminal vesicles provide fluid that “nourishes” sperm.
- Bulbourethral gland and prostate gland create a fluid
that makes sperm resistant to acid.
- Sperm + Glandular secretions = SEMEN.

8. Hormones
Chemical messengers sent from one area
of the body to another.
In males and females, different hormones
help to control sperm production and the
menstrual cycle.

9. Female Anatomy
Ovary
Uterus
Urethra
Cervix
Clitoris

10. “The Menstrual Cycle”
Eggs begin to mature in the ovaries
before a female is born.
Growth of the eggs stop before they are
completely developed.
All the eggs remain immature until
puberty.
After puberty, several eggs begin to
mature each month.
Each egg develops inside a “follicle.”

11. “The Menstrual Cycle”
Usually only one egg makes it to maturity.
This egg will burst out of the follicle
(ovulation) and move down the oviduct.
Fertilization may or may not occur.
The uterus must be ready to accept a
fertilized egg.

12. Female Hormones
The females reproductive role is to:
1.) Make and release eggs.
2.) Nourish the developing fetus.
A mix of hormones controls these events
during the “menstrual cycle.”

14. Female Hormones
1.) FSH (Follicle stimulating hormone)
- Causes follicles to mature.
- As follicles grow they release estrogen.
2.) Estrogen
- As estrogen levels rise, another hormone (LH)
begins to rise.
3.) LH (Leutinizing hormone)
- Around day 14, LH levels shoot up. This
causes at least one follicle to burst open.
- Once the egg is released it begins to produce
progesterone.
4.) Progesterone
- If egg becomes fertilized, progesterone levels stay high.
- If egg begins to disintegrate, progesterone levels fall.
- Role of progesterone is to prepare the uterus for possible
pregnancy.

15. Birth Control
1.) Physical forms
- Condoms and diaphragms block the
sperm from getting to the egg.
2.) Chemical forms
- “The pill.” Works by preventing FSH and
LH to be released.
- Result = No ovulation. Normal menstrual
cycle proceeds.

16. Fertilization and Development
Zygote- Newly fertilized egg.
Once it begins to divide, it is called an
embryo.
Embryo continues to release
progesterone. Why?
Embryo must “implant” itself into the
uterine wall.

17. The Placenta
Transports materials back and forth to the
embryo.
Oxygen – Carbon dioxide
Nutrients (carbo’s, protein, fat)
Urea (liquid, cellular waste)
Antibodies
Teratogens

18. Maternal Health
The health of the baby depends on the
health and activities of the mother.
Smoking, drugs, alcohol, radiation, and
pathogens can all harm the fetus.
Pregnancy is divided into three month
segments called “trimesters.”

19. First Trimester
Implantation of zygote.
All vital organs are formed
Heart is formed.
Brain and spinal cord.
Sex organs.
Limbs.
Eyes and ears.

20. Second Trimester
Circulatory system is functioning.
Hair formation.
Major body changes in the mother.

21. Third Trimester
Eyes open.
Fat begins to form under the skin.
Fetus gains lots of weight.
If fetus spends a full three trimesters
inside the uterus, survival outside the
mother is very likely.

22. Birth
At nine months, the baby will position
itself with its head against the cervix.
Oxotycin (hormone) causes uterine
muscles to push baby outwards (labor).
Cervix opens up and baby is forced into
vagina.
“Afterbirth” is expelled.

23. Stopping of the Menstrual Cycle
Between ages 45 – 55 ovulation and
menstruation stop.
The shut down of ovarian and uterine
cycles is known as menopause.