c. Ducts and Accessory Glands.
(1) The epididymis is essentially a tortuous 4 to 6 meter canal that coils
upon itself on the lateral posterior border of the testis. The efferent ducts of the testis
unite to form the single ductus epididymis. The epididymis has two functions: storage of
sperm and production of one of the liquid components of seminal fluid. At its distal end,
the epididymis straightens out and joins the vas deferens.
(2) The vas deferens is a thick-walled tube about 45 centimeters long. It
extends from the epididymis to the ejaculatory duct, which opens into the prostatic
(3) The seminal vesicles are two membranous sacs, each about 5
centimeters long, and consisting of a single tube coiled upon itself. They lie along the
inferior-posterior surface of the bladder. Each terminates in a straight, narrow duct that
joins the vas deferens to form an ejaculatory duct. The vesicles secrete a liquid that
forms part of the seminal fluid.
(4) The two ejaculatory ducts are located on either side of the median plane.
Union of the seminal vesicle duct and the end of the vas deferens forms each. Each
ejaculatory duct is a short tube, about 2 centimeters long, that passes through the base
of the prostate gland and opens into the prostatic urethra. During coitus, fluid from the
seminal vesicles and sperm from the vas deferens are ejected into the prostatic urethra.
(5) The prostate gland (figure 3-11) is a firm, partly glandular and partly
fibro, muscular mass of tissue surrounding the prostatic portion of the urethra. It is
pyramidal in shape with its apex directed inferiorly and its base directed superiorly. The
outer surface of the base is also in contact with the inferior aspect of the bladder. The
prostate gland secretes a thin, slightly alkaline fluid into the prostatic urethra that
neutralizes the acid conditions in the urethra and also provides a medium for sperm
(6) Cowper's glands (bulbourethral glands) are two small, somewhat lobed
bodies about the size of a pea, located just above the bulb of the penis, one on each
side of the urethra. Secretions from Cowper's glands form part of the seminal fluid.
d. The Penis.
(1) The penis consists of longitudinal columns of erectile tissue bound
together with fibrous connective tissue and surrounded by skin.
(2) The corpus spongiosum penis surrounds the urethra, which is the
passageway for both semen and urine. Distally, the corpus spongiosum penis is
enlarged into the glans penis and contains the external urethral orifice. The circular fold
of skin extending down over the glans penis is called the prepuce or foreskin.