FORUMS FOR HUMAN SEXUALITY HEALTH
KarruechesTwin
strong6_ppt_ch04.pptChapter Four
Male Sexual Anatomy, Physiology, and Response
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
External Structures
- The penis
- The scrotum
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
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
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
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
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
Internal Structures
- Epididymis
- C shaped structure on the back of the teste
- Sperm mature in vas deferens
- Vas Deferens
- The ducts that carry sperm from testicles to urethra for ejaculation
- Vas deferens joins the ejaculatory duct within prostate gland
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
- Cowper’s (bulbourethral) glands
- Secrete thick clear mucus prior to ejaculation
- Urethra
Other structures
- Breasts
- Anus
- Buttocks
- Rectum
Male Sexual Physiology
- Production of hormones
- Spermatogenesis
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
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
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
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
Summary
- Male sex organs
- Sexual physiology
- Sexual response
