penis
Part of the male reproductive
system. The penis, the male copulatory organ, is a cylindrical pendant
organ located anterior to the scrotum and functions to
transfer sperm to the vagina.
The penis consists of three columns of erectile tissue that are wrapped
in connective tissue and covered with skin. The two dorsal columns are the
corpora cavernosa. The single, midline ventral column surrounds
the urethra and is called the corpus
spongiosum.
The penis has a root, body (shaft), and glans penis. The
root of the penis attaches it to the pubic arch and the body is the visible,
pendant portion. The corpus spongiosum expands at the distal end to form
the glans penis. The urethra, which extends throughout the length of the
corpus spongiosum, opens through the external urethral orifice at the tip
of the glans penis. A loose fold of skin, called the prepuce,
or foreskin, covers the glans penis.
Just before orgasm, the penis, which is at its maximum length, exudes drops
of semen (seminal fluid). These may contain
viable sperm which is why withdrawal is ineffective as a contraceptive method.
On orgasm, muscular contractions occur at the base of the penis and bring
about ejaculation. Related entry
• male sexual
response Related category
• ANATOMY
AND PHYSIOLOGY Source: National
Cancer Institute
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