Chapter 27
The Reproductive System
1053
27
rate ever recorded. However, antibiotic-resistant strains are be-
coming increasingly prevalent. Currently, cefriaxone is the an-
tibiotic used most ofen to treat gonorrhea.
Syphilis
Syphilis
(siF
9
ĭ-lis), caused by the corkscrew-shaped bacterium
Treponema pallidum
, is usually transmitted sexually, but it can
be contracted congenitally From an inFected mother. ±etuses
inFected with syphilis are usually stillborn or die shortly afer
birth.
Te bacterium easily penetrates intact mucosae and abraded
skin. Within a Few hours oF exposure, an asymptomatic body-
wide inFection is in progress. Afer an incubation period oF two
to three weeks, a red, painless primary lesion called a
chancre
(shang
9
ker) appears at the site oF bacterial invasion. In males,
this is typically the penis, but in Females the lesion ofen goes
undetected within the vagina or on the cervix. Te chancre ul-
cerates and becomes crusty, and then it heals spontaneously and
disappears within a Few weeks.
IF syphilis is untreated, its secondary signs appear several
weeks later. A pink skin rash all over the body is one oF the first
symptoms. ±ever and joint pain are common. Tese signs and
symptoms disappear spontaneously in three to twelve weeks.
Ten the disease enters the
latent period
and is detectable only
by a blood test. Te latent stage may last a person’s liFetime (or
the immune system may kill the bacteria), or it may be Followed
by
tertiary syphilis
.
²ertiary syphilis is characterized by
gummas
(gum
9
ahs), de-
structive lesions oF the CNS, blood vessels, bones, and skin. Pen-
icillin is still the treatment oF choice For all stages oF syphilis, but
the number oF recorded cases continues to increase in the U.S.
Chlamydia
Chlamydia
(klah-mid
9
e-ah;
chlamys
5
cloak) is a largely undi-
agnosed, silent epidemic that is currently on the rise in college-
age people. It inFects perhaps 4–5 million people yearly, making
it the most common bacterial sexually transmitted inFection in
the United States.
Chlamydia is responsible For 25–50% oF all diagnosed cases
oF pelvic inflammatory disease (and, consequently, at least a
one-in-Four chance oF ectopic pregnancy). Each year more than
150,000 inFants are born to inFected mothers. About 20% oF men
and 30% oF women inFected with gonorrhea are also inFected by
Chlamydia trachomatis
, the causative agent oF chlamydia.
Chlamydia
is a bacterium with a viruslike dependence on
host cells. Its incubation period within the body cells is about
one week. Symptoms include urethritis (involving painFul, Fre-
quent urination and a thick penile discharge); vaginal discharge;
abdominal, rectal, or testicular pain; painFul intercourse; and
irregular menses. In men, it can cause arthritis as well as wide-
spread urogenital tract inFection. In women, 80% oF whom
suffer
no
symptoms From the inFection, it is a major cause oF
sterility. Newborns inFected in the birth canal tend to develop
conjunctivitis (specifically,
trachoma
, a painFul eye inFection
that leads to corneal scarring iF untreated (ofen the case in
Although the Female libido was Formerly believed to be
prompted by testosterone, new studies indicate that dehydroep-
iandrosterone (DHEA), an androgen produced by the adrenal
cortex, is in Fact the male sex hormone associated with desire
in Females.
Check Your Understanding
35.
Which gonadal hormone causes the secondary sex
characteristics to appear in a young woman?
36.
Which gonadal hormone promotes epiphyseal closure in
both males and females?
For answers, see Appendix H.
Sexually Transmitted Infections
Indicate the infectious agents and modes of transmission
of gonorrhea, syphilis, chlamydia, trichomoniasis, genital
warts, and genital herpes.
Sexually transmitted infections (STIs)
, also called
sexually
transmitted diseases
(
STDs
) or
venereal diseases
(
VDs
), are inFec-
tious diseases spread through sexual contact. Te United States
has the highest rates oF inFection among developed countries.
Over 12 million people in the U.S., a quarter oF them adoles-
cents, get S²Is each year. Latex condoms can help prevent the
spread oF S²Is, and their use is strongly encouraged.
As a group, S²Is are the single most important cause oF re-
productive disorders. Until recently, the bacterial inFections
gonorrhea and syphilis were the most common S²Is, but now
viral diseases have taken center stage. AIDS, the most notori-
ous S²I, is caused by HIV, the virus that cripples the immune
system (see Chapter 21). Here we Focus on other important bac-
terial and viral S²Is: gonorrhea, syphilis, chlamydia, trichomo-
niasis, genital warts, and genital herpes.
Gonorrhea
Te causative agent oF
gonorrhea
(gon
0
o-re
9
ah) is
Neisseria
gonorrhoeae
, which invades the mucosae oF the reproductive
and urinary tracts. Tese bacteria are spread by contact with
genital, anal, and pharyngeal mucosal surFaces. Commonly
called “the clap,” gonorrhea occurs most Frequently in adoles-
cents and young adults.
In men, the most common symptom oF gonorrhea is
ure-
thritis
, inflammation oF the urethra accompanied by painFul
urination and discharge oF pus From the penis (penile “drip”).
Symptoms vary in women, ranging From none (about 20% oF
cases) to abdominal discomFort, vaginal discharge, abnormal
uterine bleeding, and occasionally, urethral symptoms similar
to those seen in males.
In men, untreated gonorrhea can cause urethral constriction
and inflammation oF the entire male duct system. In women, it
causes pelvic inflammatory disease and sterility. With the ad-
vent oF antibiotics these complications have declined, and cases
oF gonorrhea in the United States have dropped to the lowest
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