1. Male Sexual Anatomy, Physiology, and Response
Chapter Four
Male Sexual Anatomy, Physiology, and Response
HESS 503 Human Sexuality

2. Male Sex Organs: What Are They for?
Sex organs serve a reproductive function
Also serve other functions:
Bringing pleasure to self
Giving pleasure to others
May serve to attract potential sexual partners
Sharing of genital sexuality can play a bonding role in relationships
HESS 503 Human Sexuality

3. External Structures
The penis
The scrotum
HESS 503 Human Sexuality

4. External Male Sexual Structures
Circumcised vs. Intact Penis
HESS 503 Human Sexuality

5. The Penis Penis: from Latin word for tail Three main sections:
organ through which sperm and urine pass
Three main sections:
Root: attaches penis within the pelvic cavity
Shaft: contains 3 parallel columns of erectile tissue
Corpora cavernosa: 2 columns along the front surface
Corpus spongiosum: runs beneath corpora cavernosa, also forms the glans
HESS 503 Human Sexuality

6. Cross section – shaft of penis
Anterior View
HESS 503 Human Sexuality

7. The Penis Glans penis: head of penis; most sensitive
Corona: rim at base of the glans
Frenulum: on underside of penis; triangle of sensitive skin
Foreskin: sleeve-like covering of the glans
Circumcision
Urethra: a tube that transports urine and semen
When penis erect, urinary duct is blocked
HESS 503 Human Sexuality

8. The Penis: Myths
Penis size not linked to body size or weight, muscular structure, race or ethnicity or sexual orientation
No relationship between penis size and ability to have sexual intercourse or satisfy a partner
HESS 503 Human Sexuality

9. The Scrotum A pouch of skin that holds the two testicles
Scrotum skin more heavily pigmented
Sparsely covered with hair
Divided in the middle by a ridge of skin
Testicle temperature control: 93°F
HESS 503 Human Sexuality

10. Internal Structures Testes:
Two major functions: sperm and hormone production
Shaped like olives; 1.5” long and 1” diameter.
Size and weight decrease as men age
Not usually symmetrical in the way they hang
Suspended by spermatic cord
Within each testicle, there are about 1000 Seminiferous tubules: Production of sperm takes place in these tubes
HESS 503 Human Sexuality

11. Internal Lateral View of Male Sex Organs
HESS 503 Human Sexuality

12. Internal Structures Epididymis Vas Deferens
C shaped structure on the back of the teste
Sperm mature in epididymis
Vas Deferens
The ducts that carry sperm from testicles to urethra for ejaculation
Vas deferens joins the ejaculatory duct within prostate gland
HESS 503 Human Sexuality

13. Internal Lateral View of Male Sex Organs
HESS 503 Human Sexuality

14. Cross section – Epididymis, Vas deferens
HESS 503 Human Sexuality

15. Internal Structures Seminal vesicles Prostate gland
Secrete fluid that makes up 60% of semen
Prostate gland
Secretes fluid that makes up 30-35% of semen
Can be stimulated in anal play
Cowper’s (bulbourethral) glands
Secrete thick clear mucus prior to ejaculation
Urethra
HESS 503 Human Sexuality

16. Internal Lateral View of Male Sex Organs
HESS 503 Human Sexuality

17. HESS 503 Human Sexuality

18. Other structures
Breasts
Anus
Buttocks
Rectum
HESS 503 Human Sexuality

19. Male Sexual Physiology
Production of hormones
Spermatogenesis
HESS 503 Human Sexuality

20. Male Reproductive Hormones
Testosterone
Acts on seminiferous tubules to produce sperm
Regulates sex drive
Is responsible for development of secondary sex characteristics in puberty
Influences growth of bones and muscle mass
HESS 503 Human Sexuality

21. Hormone Regulation
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22. Male Reproductive Hormones
HESS 503 Human Sexuality

23. Spermatogenesis Ongoing process from puberty onward
Sperm produced within seminiferous tubules of testicles (64-72 days)
Several 100 million sperm produced daily
20 days for sperm to travel through epididymis
During this time they become fertile and motile
Upon ejaculation, sperm expelled through urethra by muscular contractions
HESS 503 Human Sexuality

24. Spermatogenesis
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25. Mature Spermatocyte
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26. Male Sexual Response Erection
Blood vessels expand and increase blood in penis
Veins that normally carry blood out are compressed, leading to engorgement of penis
Secretions from Cowper’s glands appear at tip
HESS 503 Human Sexuality

27. HESS 503 Human Sexuality

28. Ejaculation and Orgasm
Emission stage
Sperm sent into vas deferens
Rhythmic contractions begin
Feeling of ejaculatory inevitability
Expulsion stage
Rapid contractions
Semen spurts from urethral opening
Orgasm
Intensely pleasurable physical sensations that usually accompany ejaculation
Followed by refractory period
HESS 503 Human Sexuality

29. HESS 503 Human Sexuality