Webster's New World Medical Dictionary

Epstein-Barr virus
A virus in the herpes family
that is best known as the cause of infectious
mononucleosis (also called mono and glandular
fever). Abbreviated EBV. EBV infection is character-
ized by fatigue and general malaise. Infection with
EBV is common and is normally temporary and
minor. However, in some individuals EBV can trig-
ger chronic illness, including immune and lympho-
proliferative syndromes. It is a particular danger to
people with compromised immune systems, includ-
ing those with AIDS. Treatment is with antiviral med-
ication and rest. Also known as human herpesvirus
4 (HHV-4).
ERCP
Endoscopic retrograde cholangio-pancre-
atography, a diagnostic procedure used to examine
diseases of the liver, bile ducts, and pancreas. ERCP
is usually performed under intravenous sedation
rather than general anesthesia. ERCP provides
important information that cannot be obtained by
other means. Therapeutic measures can often be
taken at the time of ERCP to remove stones in the
bile ducts or to relieve obstructions of the bile
ducts.
erectile dysfunction
A consistent inability to
sustain an erection sufficient for sexual intercourse.
Commonly known as impotence. Medically, the term
erectile dysfunction is used to properly differentiate
this form of impotence from other problems that
interfere with sexual intercourse, such as disease,
injury, drug side effects, or a disorder that impairs
the nerve supply or the blood flow to the penis.
Other forms of impotence include lack of sexual
desire and problems with ejaculation and orgasm.
Erectile dysfunction is treatable in all age groups,
and treatment includes using medication (notably
Viagra) and penile implants. Abbreviated ED.
erection, penile
The state of the penis when it is
filled with blood and becomes rigid. The penis con-
tains two chambers called the corpora cavernosa,
which run the length of the organ, are filled with
spongy tissue, and are surrounded by a membrane
called the tunica albuginea. The spongy tissue con-
tains smooth muscles, fibrous tissues, spaces, veins,
and arteries. The urethra, which is the channel for
urine and ejaculate, runs along the underside of the
corpora cavernosa. Erection begins with sensory
and mental stimulation. Impulses from the brain
and local nerves cause the muscles of the corpora
cavernosa to relax, allowing blood to flow in and fill
the open spaces. The blood creates pressure in the
corpora cavernosa, making the penis expand. The
tunica albuginea helps to trap the blood in the cor-
pora cavernosa, thereby sustaining erection.
Erection is reversed when muscles in the penis con-
tract, stopping the inflow of blood and opening out-
flow channels.