1. Chapter 5 Male Sexual Anatomy and Physiology

2. Male Sexual Anatomy
The penis
foreskin, glans, shaft, & root

3. Male Sexual Anatomy (cont.)
Fig 5.1a Interior structure of the penis: (a) view from above.

4. Male Sexual Anatomy (cont.)
The penis
corpus carvernosa
corpus spongiosum
Fig 5.1b Interior structure of the penis: (b) cross section of the penis

5. Male Sexual Anatomy (cont.)
The penis; corona, frenulum
Fig 5.2 This figure, a view of the underside of the penis, shows the location of the corona and frenulum—two areas on the penis that harbor a high concentration of sensitive nerve endings.

6. Male Sexual Anatomy (cont.)
The scrotum
a sac or pouch with two chambers
muscle layer (tunica dartos)
pulls sac closer to body in cold temperatures
spermatic cord

7. Male Sexual Anatomy (cont.)
Fig 5.3 The scrotum and the testes. The spermatic cord can be located by palpating the scrotal sac above either testicle with thumb and forefinger.

8. Male Sexual Anatomy (cont.)
The testes
secrete male hormones
produce sperm
cryptorchidism: undescended testis
self-exam is recommended

9. Male Sexual Anatomy (cont.)
Fig 5.4 Underlying structures of the scrotum. This illustration shows portions of the scrotum cut away to reveal the cremasteric muscle, spermatic cord, vas deferens, and a testis within the scrotal sac.

10. Male Sexual Anatomy (cont.)
The testes
seminiferous tubules
site of sperm production
interstitial cells
Major source of androgen
epididymis: sperm maturation

11. Male Sexual Anatomy (cont.)
Fig 5.5a Internal structure of a testis. Sperm are produced in the seminiferous tubules and transported to the epididymis, which serves as a storage chamber.

12. Male Sexual Anatomy (cont.)
The vas deferens
moves sperm from scrotum to ejaculatory duct through prostate
ejaculatory ducts open into the urethra

13. Male Sexual Anatomy (cont.)
Fig 5.6 Male sexual anatomy: A cross-section side view of the male reproductive organs.

14. Male Sexual Anatomy (cont.)
The seminal vesicle
secretes 70% of seminal fluid
The prostate gland
secretes about 30% of seminal fluid
alkaline fluid helps counteract acidity

15. Male Sexual Anatomy (cont.)
The Cowper's glands
attaches to urethra just below prostate
secretes fluid before ejaculation
may contain active, healthy sperm

16. Male Sexual Anatomy (cont.)
Semen (seminal fluid)
about 1 teaspoon
200 to 500 million sperm

17. Male Sexual Functions Erection autonomic nervous system
arteries expand
blood outflow cannot keep up with inflow  tumescence
psychogenic & physiogenic factors

18. Male Sexual Functions (cont.)
Fig 5.7a Male sexual anatomy during ejaculation: (a) the emission phase.

19. Male Sexual Functions (cont.)
Ejaculation
spinal reflex triggers two phases
emission: fluid in urethral bulb
expulsion: semen expelled
retrograde ejaculation
nocturnal emission

20. Male Sexual Functions (cont.)
Fig 5.7b Male sexual anatomy during ejaculation: (b) the expulsion phase.

21. Concerns About Sexual Functioning
Penis size
symbol of virility
erect penises show less variation than flaccid
size not related to sexual satisfaction
penile augmentation
genital retraction syndrome (koro)

22. Concerns About Sexual Functioning (cont.)
Circumcision
hygienic value & risk for STDs?
medical risks
AAP: moderate opposition
Phimosis: extremely tight foreskin

23. Concerns About Sexual Functioning (cont.)
Fig 5.9 Circumcision, the surgical removal of the foreskin.

24. Male Genital Health Concerns
Penis health-care issues
cleanliness: smegma, infections
reaction to vaginal secretions
injuries
penile cancer

25. Male Genital Health Concerns (cont.)
Testicle health-care issues
testicular cancer
rare, but more common in young men (15 to 34 years)
sign: hard or irregular mass
Survival > 90% if detected early

26. Male Genital Health Concerns (cont.)
Prostate health-care issues
prostate diseases
prostatitis: enlarged & inflamed
benign prostatic hyperplasia
prostate cancer
PSA test
Treatment options for prostate cancer