Chapter Four

1
Chapter Four

• Male Sexual Anatomy, Physiology, and Response

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

3
External Structures

• The penis
• The scrotum

4
The Penis

• Penis from Latin word for tail
• 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

5
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 tube that transports urine and semen
• When penis erect, urinary duct is blocked

6
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

7
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 93F

8
Internal Structures

• Testes
• Two major functions sperm and hormone production
• Shaped like olives
• Size and weight decrease as men age
• Not usually symmetrical
• Suspended by spermatic cord
• Within each testicle, there are Seminiferous
  tubules

9
Internal Structures

• Epididymis
• C shaped structure on the back of the teste
• Vas Deferens
• The ducts that carry sperm from testicles to
  urethra for ejaculation
• Joins the ejaculatory duct within prostate gland

10
Internal Structures

• Seminal vesicles
• 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
• Cowpers (bulbourethral) glands
• Secrete thick clear mucus prior to ejaculation
• Urethra

11
Other structures

• Breasts
• Anus
• Buttocks
• Rectum

12
Male Sexual Physiology

• Production of hormones
• Spermatogenesis

13
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

14
Spermatogenesis

• Ongoing process starting at puberty
• sperm produced within seminiferous tubules of
  testicles (64-72 days)
• 20 days for sperm to travel through epididymis
• Upon ejaculation, sperm expelled through urethra
  by muscular contractions

15
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 Cowpers glands appear at tip

16
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