1. Male Sexual Anatomy and Physiology
Chapter 6

2. Figure 6.1 The internal structure of the penis.

3. Figure 6.2 The male reproductive organs.

4. Figure 6.4 Internal structure of the testicle.

5. Colored scan of seminiferous tubules, each containing a swirl of forming sperm cells (in blue).

6. The Ejaculatory Route

7. Ejaculation
Begins in the spinal cord once a threshold is reached, and proceeds until the conclusion
Once the threshold is reached:
Epididymis, seminal vesicles, and prostate empty their fluids into the urethral bulb
A sphincter closes off the bladder
5-15 contractions at the base of the penis squeeze the urethral bulb
Ejaculate is expelled
Orgasm
Return to flaccid state

8. Ejaculate/Semen 2-5 milliliters of fluid
million sperm per milliliter
Few sperm reach the ovum
Sperm work together in order to fertilize the egg
Semen coagulates upon ejaculation; this helps it remain in the vagina and travel into the uterus
5-20 minutes later it thins out due to Prostatic enzymes

9. Figure 6.6 Puberty: The cycle of male hormones.

10. Andropause
Testosterone levels decrease about 1% per year after 40 years of age
In the 70s and 80s, andropause occurs in 2% of men: : decreased spermatogenesis, thinner ejaculate, less ejaculatory force
Decreased testosterone: libido decreases, fatigue, mood disturbances, decreased strength
Controversy over androgen replacement therapy; has increased significantly in U.S.; no evidence to support link to prostate cancer

11. Disorders of the Male Reproductive Organs
Figure 6.7 Although the testicles of a fetus begin high in the abdomen, they must descend into the scrotum during fetal development. If they do not, the male may become infertile.

12. Disorders of the Male Reproductive Organs (Cont.)
Figure 6.8 Testicular torsion can occur after exercise, sexual intercourse, and even while sleeping.

13. Disorders of the Male Reproductive Organs (Cont.)
Priapism – abnormally prolonged and painful erection that is not associated with sexual desire or excitement; blood is trapped in erectile tissue; common causes include diseases, spinal cord injuries, and drug use; immediate treatment necessary
Peyronie’s disease – painful curvature of the penis making penetration impossible; cause is unknown; may disappear within 2 years, or require drugs or surgery

14. Other Conditions that Affect the Male Reproductive Organs
Inguinal hernia – intestine goes through an abdominal opening into the scrotum, creating a bulge; can be due to heavy lifting and straining; surgery may be required
Hydrocele – fluid accumulates around testicle; common in newborns
Anabolic-androgenic steroid abuse – synthetic testosterone can increase muscle mass and endurance; many physical, psychological, and emotional side effects, including erectile problems

15. Cancers of the Male Reproductive Organs
Male breast cancer
Penile cancer
Testicular cancer
Prostate cancer

16. Testicular Cancer

17. A prostate exam.

18. Prostate Cancer
Prostate glands enlarge with age and this is typically unproblematic, other than interfering with urination
Prostate cancer is one of the most common in American men, typically in men over 50 years
Risk factors: age, high fat diet, race, heredity, BRCA gene
Symptoms: pain in the lower back, pelvis, or upper thigh, and urinary abnormalities
Detected through rectal exam and blood test

19. Prostate Cancer (Cont.)
Prostate-Specific Antigen (PSA) is blood test for overproduction of molecules made by prostate cells
Treatments: “watchful waiting” in older men; radical prostatectomy; radiation; vaccine that that uses patient’s white blood cells to attack cancer cells