Male Sexual Anatomy
 The penis
 foreskin, glans, shaft, & root
Male Sexual Anatomy
 Penis - formed of three cylindrical masses of erectile tissue - enclosed
in separate fibrous coverings - held together by a covering of skin
 Root at base of penis, divides into crura which are attached to the
pelvic bones
 Glans is at the tip of the penis and is the most sensitive part for
most men - covered by prepuce or foreskin which may be removed
by a surgical procedure called circumcision
 smegma - secretion that can accumulate under foreskin of penis
(or clitoris) – uncircumcised men should clean beneath the
foreskin thoroughly when they wash to prevent excess
accumulation of smegma
 Corona (crown) - ridge between glans and foreskin (see next slide)
 Frenulum - connects glans to shaft on underside of penis (see next
slide)
Corona and Frenulum
http://www.thevisualmd.com/searchimg/?idu=12302&q=glans%20of%20penis
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.
 Shaft - contains spongy tissue which fills with blood
when a man is aroused, leads to erection (there is no
bone in the penis)


Cavernous bodies (corpus cavernosum) - on top - 2 of them
Spongy body (corpus spongiosum) underneath - 1 only - urethra
runs through it
Penises come in a variety of shapes and sizes…
http://www.erectionphotos.com/frames_index.htm
 The Scrotum
 loose pouch or sac of skin beneath
the penis with two chambers that
hold the testicles, one testicle in
each sac
 testes are suspended in the sacs by
the spermatic cord which carries
sperm out of the testes in the vas
deferens
 cremaster muscles pull testes
closer to body in cold
temperatures – to produce viable
sperm, the testes must be at the
right temperature, and these
muscles allow testes to be raised
or lowered to control the
temperature
The spermatic cord can be located by
palpating the scrotal sac above either
testicle with thumb and forefinger.
 Testes http://www.youtube.com/watch?v=gAnMymnJiLM
 Spermatogenesis: process of
sperm production
 Seminiferous tubules are the
site of sperm production
 sperm maturation occurs
in the epididymus
(about 20 feet long) on
the back of each testicle
 Interstitial cells are
located between the
seminiferous tubules and
are the major producer of
androgens in men
Internal structure of a testis. Sperm are
produced in the seminiferous tubules and
 200 million sperm/day!!
transported to the epididymis, which serves
as a storage chamber.
Vas Deferens
 Extension of epididymus (about 18" long) – vas is carried into pelvic
cavity through the spermatic cord, over the top and down back/side of
bladder –
 Vasectomy involves severing the vas deferens
 Seminal vesicles - two pouch-like structures between the bladder and the
rectum - function not completely understood – they secrete an alkaline fluid
rich in fructose - sperm become motile here and can propel themselves (got to
this point via cilia in ducts)
 Ejaculatory ducts - formed from the union of the vas deferens and the
excretory duct of the seminal vesicles
 Prostate gland - doughnut shaped gland just below the bladder - thin alkaline
secretions counteract acidity in male urethra and in the vagina –
 Cowper's glands (or bulbourethral glands)
 pea-sized - lie just below prostate - connect to urethra by a
duct - secrete a slippery substance when a man is sexually
aroused - alkaline - helps lubricate flow of seminal fluid
through urethra
 can contain active sperm and cause pregnancy without
ejaculation occurring
 Semen (or seminal fluid)
 one teaspoon of fluid – one ejaculation contains 200-500
million sperm which - provide only 1% of volume - rest from
seminal vesicles (70%), prostate (30%) and Cowper's gland
 semen of a healthy man is not harmful if swallowed – but
semen can transmit HIV from an HIV-positive man
Erection
Controlled by the autonomic nervous
system (which is generally involuntary in its
actions) - arteries expand, and when blood
outflow can’t keep up with inflow,
tumescence (erection) occurs
Erections occur from birth (and apparently
before), occur during REM sleep throughout
life – clearly not always due to sexual
stimulation
Psychological factors can enhance or inhibit
erections
 Process of ejaculation occurs in two stages;
 Emission phase: The cremaster muscle pulls the testes
up close to the body preparing to release sperm

Ejaculatory inevitability: During intercourse, the point
when semen is about to be secreted
Expulsion phase: Ejaculatory ducts: Two short
ducts located within the prostate gland that transport
sperm to the urethra prior to ejaculation
Penis Size
Many cultures are preoccupied with penis size, not just
a U.S. phenomenon - worship of the penis is one of the
oldest known religious practices (as is worship of the
goddess and female fertility)
Large size not related to better sex - partner preferences
vary
Some pain occurs if sizes don’t match
Size not related to size of other body parts
Bigger differences in size when flaccid than when
aroused, i.e., smaller flaccid penis usually increases in
size more during erection than a larger flaccid penis
The largest?
Did you know?
A study on penis size with over 3,000 men found that most
men who sought penis enhancement because they were
dissatisfied with their penises were within the normal size
range and greatly overestimated the size of an average penis
(Dillon, et al., 2008). These men thought the average flaccid
size was about 5 inches, although some thought it was as long
as 6.5 inches. Men get their ideas about penis size mostly
from porn, where male performers have penises that are
longer than average. In reality, a 7-inch erect penis would
place you in the 99th percentile.
Penis Enlargement
This is the before photo
Penis Enlargement
This is the after photo
Fat injection
Cutting the ligaments
Penis Enlargement
 Some men go for the stretch
(“gelking”) with weights
attached
Male Genital Health Concerns
 Most often want to consult with a urologist for male genital health
concerns (if primary care doctor can’t take care of problem)
 Penis health-care issues
 cleanliness: uncircumcised men need to be sure to remove smegma
from under the foreskin
 it is possible for penis to have a negative reaction to some vaginal
secretions resulting in a condition similar to eczema
 some sex toys (gadgets) are hazardous to the penis, e.g., cock rings
that help maintain an erection can destroy tissue in the penis if left
on too long, and text says they should never be used
 NEVER masturbate with vacuum cleaner type devices
Cancer
 Penile cancer: rare, but deadly if not treated early
 Testicular cancer: rare, but more common in young men
(20-35 yrs old)- results in hard or irregular mass in a testicle
sometimes grows rapidly, and it is very important to detect
and treat early…p. 120 exam