1. Reproductive system
Produces offspring

2. The Reproductive System
Gonads—primary sex organs
Testes in males
Ovaries in females
Gonads produce gametes (sex cells) and secrete hormones
Sperm—male gametes
Ova (eggs)—female gametes

3. Sex cell size and structure
Meiosis
Males—produces four functional sperm
Females—produces one functional ovum and three polar bodies
Sex cell size and structure
Sperm are tiny and equipped with nutrients in seminal fluid
Egg is large and has nutrient reserves to nourish the embryo until implantation

4. Male Reproductive System Overview
Testes
Duct system
Epididymis
Vas deferens
Urethra

5. The testes also produce testosterone, the male hormone.
What is the difference between the urethra and a garden hose?
There is a vas deferens....
Testes –
make sperm via meiosis.
2-4 million every day
The testes also produce testosterone, the male hormone.

6. Testosterone Production
Functions of testosterone
Stimulates reproductive organ development
Underlies sex drive (desire to mate/breed/procreate)
Causes secondary sex characteristics
Deepening of voice
Increased hair growth
Enlargement of skeletal muscles
Thickening of bones

7. Epididymus - collects mature sperm which eventually exits through the vas deferens
Vas deferens -  tube where sperm travel to the outside of the body.  
Urethra - extends from bladder to tip on penis. Carries both urine & sperm 
Sterilization:
Vasectomy - the vas deferens is cut to prevent sperm leaving. Testosterone is still produced. Sperm can’t leave body
Castration – removal of testes. No sperm. No testosterone

8. External genitalia Scrotum Divided sac of skin outside the abdomen
Holds & protects testes
Maintains tests at a slightly lower body temperature to protect sperm

9. Penis Covered by sheath. organ of copulation.
Deposits sperm into female at breeding. Long rod-like tissue.

10. Sheath – protects the penis from injury

11. WORD BANK Vas deferens Bladder Vas deferens Scrotum Urethra Prostate
Seminal Vesicle
Prostate
Urethra
Prostate
Epididymus
Epididymus
Bladder
Teste
Scrotum
Teste
Seminal Vesicle

12. rooster

13. Structure of a Sperm
Figure 16.5b

14. FEMALE REPRODUCTION Main Structures Ovary Uterus Fallopian Tubes
Vagina
Cervix

15. OVARY  - this is where the eggs are produced through cell division (MEIOSIS)
each ovary takes turns releasing eggs every month, twins occur if two eggs are released
Females are born with all their eggs (~400,000)
Ovaries secrete estrogen
Estrogen is responsible for the appearance of secondary sex characteristics of females

17. Follicles "blister like" structures that form on ovaries
A maturing ovum is held within each follicle
Release of the ova (egg) = Ovulation

18. Fallopian tubes Attached to ovaries & uterus Receives egg from ovary
Where fertilization occurs

19. where the fetus (baby) develops Regions Body – main portion
The uterus
where the fetus (baby) develops
Regions
Body – main portion
Cervix – separates the uterus & vagina
Closes during pregnancy  

20. Cervix
a thick-walled structure made up of several folds and rings of muscle tissue

21. Vagina Extends from cervix to exterior of body (vulva) Birth canal
Receives male penis during intercourse

22. WORD BANK
Fallopian Tubes
Ovary
Cervix
Fallopian Tubes
Vagina
Ovary
Uterus
Uterus
Cervix
Vagina

23. FERTILIZATION normally occurs in the Fallopian Tubes
The fertilized egg (zygote) implants in the uterus

24. FERTILIZATION & PREGNANCY
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

26. Functions of the Placenta
Forms a barrier between mother and embryo (blood is not exchanged)
Delivers nutrients and oxygen
Removes waste from embryonic blood
Becomes an endocrine organ (produces hormones) and takes over for the corpus luteum (by end of second month) by producing
Estrogen
Progesterone
Other hormones that maintain pregnancy

27. Identical twins One zygote Splits in 2 No one knows why!
Completely random = does NOT run in families
Same exact DNA
Nature’s clones

28. Fraternal Twins
2 separate eggs get fertilized with 2 different sperm cells
More than one egg got released during ovulation
Siblings
Can be sisters
Brothers
Brother and sister
Tends to run in families

29. Conjoined Twins Used to be called “Siamese” twins
First well known case was in Siam
Identical twins that never completely separated during development
Sometimes can be separated, depending on what is shared.

30. Virtual Pig