The foreskin (prepuce) has been described as a simple fold of skin, with
its structures and functions ignored. The foreskin actually is a
complex organ, an integral part of the penis, with many important
functions.
The foreskin protects the glans and the urinary meatus (opening) and performs many other integrated functions.
The
immunological functions of the foreskin help protect the body from
pathogens. The sphincter action of the preputial orifice prevents entry
of infectious contaminants. Glands secrete lysozyme, an enzyme that
breaks down cell walls of pathogens. The sub-preputial moisture
lubricates and protects the mucosal lining of the glans and inner
foreskin. The high vascularization of the foreskin brings cells to fight
infection, while Langerhans cells secrete cytokines, proteins that
regulate the intensity and duration of immune responses, and langerin, a
substance that provides a barrier to HIV infection.
The
foreskin provides the skin necessary to accommodate a full erection.
Even when erect, the foreskin has a gliding action that provides
additional sexual pleasure to the man and his partner. The gliding
mechanism of the foreskin facilitates insertion and reduces friction and
chafing during sex. The foreskin also provides a seal, keeping the
secretions necessary for comfortable intercourse contained within the
vagina.
The foreskin contains 20,000–70,000 erogenous nerve
endings, the majority of which are concentrated in the ridged band,
which encircles the inner opening of the foreskin. When the penis is
flaccid, the nerve endings are protected but, when erect, they are
exposed. Circumcision removes about three-fourths of the nerve endings
in the penis, leaving the circumcised penis severely disabled by
comparison.
These nerve endings allow a man to modulate his
sexual experience. Without them, a man may feel pleasure, but, without
warning, reaches ejaculation quickly. The greatest complaint of
circumcised males is premature ejaculation.
Without the
foreskin’s protection, the glans becomes keratinized (calloused). The
free nerve endings in the glans become buried in layers of callused
skin. Many circumcised males complain about sexual dysfunction and
impotence because they lack the feelings and feedback meant to be
provided by nerve endings that were amputated with circumcision.
Circumcised men are 4.5 times more likely to be diagnosed with erectile
dysfunction than intact men.
The foreskin plays an important role in protection, sexual function, and sexual pleasure.