B115 Male Reproductive Anatomy & Physiology

1. B115 Male Reproductive Anatomy & Physiology

2. Male Reproductive Terms Male Reproduction Process Glands Semen Evaluation Abnormalities Fertilization Lesson Outline

3. Male Reproductive Terms • Testicle: The male sex gland that produces sperm. • Spermatozoa: The male’s sex cell that is responsible for fertilization. • Seminiferous Tubules: Small structures in the testicles that are responsible for spermatogenesis (sperm production). • Semen: Sperm and additional fluids produced by several accessory glands.

4. Male Reproductive Terms • Epididymis: Cord attached to the testicle that is responsible for sperm maturing and final development. • Vas Deferens: Tube that connects the epididymis with the urethra. Sperm cells move through here to the urethra. • Urethra: Tube that carries urine from the bladder • Seminal Vesicles: Organs which contain fluids necessary for sperm survival. • Prostate Gland: Gland that contributes seminal fluid necessary for healthy sperm.

5. Male Reproductive Terms

6. Male Reproductive Terms

7. Male Reproductive Terms

8. Male Reproduction Process • Gonadotrophin production by the hypothalamus causes the pituitary to produce FSH and LH. • These stimulate the cells of the testicle to produce testosterone, and spermatozoa or sperm. • In the tiny seminiferous tubules of the testicle, immature sperm are produced. • These sperm move to the epididymis where they fully mature and are stored prior to ejaculation.

9. Male Reproduction Process • During ejaculation, the sperm travel through the vas deferens, and into the urethra. • In the vas deferens and urethra, additional fluid from the secondary sex glands (seminal vesicles, prostate, bulbourethral glands) is added which helps keep the sperm alive. • Sperm are very sensitive to extremes in heat or cold.

10. Male Reproduction Process • The scrotum is sack like structure designed to regulate the optimal temperature for sperm production by drawing the testicles closer to the body or away from the body. • Animals that are sick, have a fever, or are fat (causing insulation for the sperm) often have lower numbers of healthy sperm. Severe cold, and stress, can also cause decreased numbers of normal sperm. • It takes 60 days for sperm to completely mature so many reproductive problems in bulls may not show up for several months.

11. Male Reproductive Tract Glands • Seminal Vesicles: • Produce a fluid that protects and transports the sperm. • Prostrate Gland: • Located near the urethra and the bladder. • Produces fluid that is mixed with seminal fluid. • Cowper’s Gland: • Produces fluid that cleans and neutralizes the urethra.

12. Semen Evaluation • Semen is evaluated on three things: • Concentration • Morphology • Motility

13. Concentration • Number of sperm cells per milliliter • Most important fertility Indicator • Average ejaculate ranges from 4 to 6 milliliters and contains 6 to 8 billion sperm cells.

14. Mobility • Microscope at 400X • 70% or more mobile cells at 40 degrees centigrade (104 F)

15. Mobility

16. Morphology • Proportion of abnormal sperm • Should not exceed 20% • Most bulls produce some abnormalities

17. Sperm Morphology

18. Double Head

19. Abnormal Head

20. Abnormal Head

21. Elongated Head

22. Swollen Neck & Tail

23. Detached Head

24. Broken Tail

25. Coiled Tail

26. Sperm Abnormalities

27. Sperm Abnormalities

28. Sperm Abnormalities

29. Sperm Abnormalities

30. Fertilization • Fertilization is the union of the sperm and the egg. • Conditions for fertilization: • Male and female compatibility • Female in Heat • Egg is mature

31. Sperm on an Egg

32. Embryos • The result of fertilization, early stage of development of the fetus.