gland. Testosterone enters the cells of these tar-

origin of the seminal vesicles is known as the

get areas and is converted to dihydrotestoster-

ejaculatory duct which enters into the urethra.

one by the enzyme 5 A reductase. It is this

dihydrotestosterone which permits the differ-

entiation of these structures into the male exter-

Development of the Prostate

nal genitalia and secondary sex organs.

Disorders of Testicular Function

and Urethral Glands

Both above and below that point where the

Disorders of testicular differentiation and devel-

ejaculatory ducts enter the urethra, numerous

glandular structures form as out-branchings

opment may thus result in the absence or delayed

from the urethral lumen. These are the anterior

secretion of these two vital testicular substances

urethral glands of Littre and Morgagni, as well

which are essential for male phenotypic deve-

as the deep urethral (bulbomembranous) glands

lopment and müllerian ductal inhibition. The

of Cowper.

resulting anomalies will vary depending upon

At about the eleventh week of fetal life, the

on the degree and time of delayed secretion.

prostate (or female homologue) develops both

With this as background,and a clear understand-

above and below the point of exit of the ejacula-

ing of the important role which the normally dif-

tory ducts as multiple outgrowths of endothe-

ferentiating testis plays on the development of

lium in that portion of the urogenital sinus

the respective genital ductal system, a closer look

(urethra) which gives rise to prostatitic urethra

at the development of each system is now in

in the male and the entire urethra in the female.

order.

These tubules form in six groups which ulti-

mately become the definitive prostatic lobes in

Male Ductal System

the male.Eventually,these prostatic buds become

surrounded by smooth muscle fibers and con-

Development

nective tissue to form the prostate gland.

In the absence of testosterone, the female

homologues of these structures form and are

While differentiating, the gonad is situated in

the epoöphoron,(appendix epidid ymis) paroö-

close proximity to the mesonephric duct. The

phoron (paradidymis), Gartner’s duct (vas def-

mesonephric tubules adjacent to this developing

erens),Skene’s glands (prostate),and Bartholin’s

gonad become continuous with the rete testes.

glands (Cowper’s glands). The Skene and Bar-

These mesonephric tubules, together with that

tholin glands can become inflamed and symp-

portion of the mesonephric duct into which

tomatic.

they drain, will develop into the epididymis on

each side and thus establish an actual urogenital

Female Ductal Development

connection.

The mesonephric tubules above and below

those which were included in the epididymal

In the developing embryo, the paired Müllerian

formation remain as rudimentary structures.

or paramesonephric ducts are positioned later-

Those above the epididymis form the appendix

ally to the mesonephric ducts. At the cephalad

of the epididymis and those below form the

end of each duct, an opening with the celomic

paradidymis.

cavity persists. This is the peritoneal ostium of

The mesonephric duct distal to that portion

the uterine tubes which later develop fimbria.

forming the epididymis will become the vas def-

The caudal end grows distally as a solid tip and

erens. Just proximal to the point where the vas

eventually crosses in front of its respective

deferens enters the urogenital sinus which forms

mesonephric duct to meet and fuse with its con-

the urethra, a saccular dilatation evaginates

tralateral mate (see Fig. 1.19).

from its wall to form the seminal vesicles. That

At first this fusion is partial, with an interme-

portion of the mesonephric duct distal to the

diate septum, but later a single canal develops