1. Animal Reproduction

2. Asexual Reproduction Produced genetically identical individuals
Examples: hydra, sponges

3. Sexual Reproduction Fusion of two haploid cells to form a diploid
Meiosis produces haploid cells
Mechanism to bring haploid cells together must be present
Mechanism to create genetic diversity

4. Fertilization
Haploid sperm and egg unite to form a diploid zygote

5. External Fertilization
Sperm spread over egg cells
Requires water
Most aquatic animals
Examples: most fish, corals, starfish
Inefficient
Spermatophore – sperm packaged into capsule
Some terrestrial animals
Examples: salamanders, scorpions, octopus

6. Internal Fertilization
Requires copulation
Most common method for terrestrial animals
Less sperm and eggs needed

7. Human Reproduction

8. Male Reproductive Organs

9. Male Reproductive Organs
Testes
Sperm and testosterone
Seminal vesicle
Fructose and prostaglandin
Prostate
Basic fluid and sperm motility factors
Bulbourethral gland
Mucus

10. Testes Produce sperm and testosterone Spermatogenesis
Spermatogonium – divides by mitosis
Meiosis I
Primary spermatocyte (2n)  secondary spermatocyte (1n)
Meiosis II
Secondary spermatocyte (1n)  spermatids (1n)
Differentiation
Spermatids (1n)  sperm (1n)

11. Testes

12. Spermatogenesis

14. Androgens – Male Sex Hormones
Main androgen is testosterone
Made by the Leydig cells of testes
Purpose
Maintain primary and secondary sex characteristics
Promote sexual behavior and sex drive
Promote spermatogenesis

15. Sperm Structure Acrosome Middle Piece Flagellum
Digests egg protective barrier to allow nucleus to enter egg
Middle Piece
Mitochondria
Flagellum
Microtubules
Controlled by centrioles

16. Female Reproductive Organs

17. Female Reproductive Organs
Ovary
Produce oocytes
Meiosis I
Produces hormones (estrogen and progesterone)
Oviduct (fallopian tube)
Transmits oocyte to uterus
Site of fertilization
Meiosis II
Uterus
Zygote implantation
Placental development

18. Ovary and Oogenesis Meiosis I Meiosis II
Inside ovary
Primary oocyte (2n)  Secondary oocyte (1n)
Meiosis II
Inside oviduct after fertilization
Secondary oocyte (1n)  Ovum (1n)
Only one egg forms, other products of meiosis form polar bodies

19. Ovary and Oviduct

20. Ovary and Oogenesis

22. Female Reproductive Cycle
Cyclic pattern (average 28 days)
Menstrual and ovarian cycles
Controlled by hormones
Gonadotropin
LH – luteinizing hormone
FSH – follicle-stimulating hormone
Ovarian hormones
Estrogen
Progesterone

23. Menstrual Cycle Three phases Menstrual flow phase (few days)
Endometrial surface lost
Proliferative phase (1-2 weeks)
Endometrium regenerates
Secretory phase (2 weeks)
Endometrium thickens
Glands develop and secreted glycogen
No embryo implantation

24. Ovarian Cycle Two phases Follicular phase Luteal phase
Primary follicle grows into a mature follicle (Graafian follicle)
Ovulation occurs at the end of this phase
Luteal phase
Follicle cells become endocrine tissue and secrete hormones

25. Menstrual and ovarian cycles
Menstrual and ovarian cycles run in parallel

26. Ovulation, Fertilization and Implantation

27. Fertilization Acrosome discharges enzymes to digest zona pellucida
Once single sperm enters egg
Egg releases enzymes that harden zona pellucida preventing other sperm from entering
Sperm nucleus enters egg and fuses with egg nucleus

28. Placenta