The =uterine= or =Fallopian tubes= (Tubæ uterinæ) act as excretory ducts
of the ovaries, since they convey the ova from the reproductive glands
to the uterus. They are not, however, in direct continuity with the
glands, but rather partly in contiguity with, and partly attached to,
them.[150] They are two flexuous tubes, about ten to twelve inches (ca.
25 to 30 cm.) long, which extend from the extremities of the uterine
cornua to the ovaries. Each is inclosed in a peritoneal fold, derived
from the external layer of the broad ligament, and termed the
=mesosalpinx=. This largely covers the outer aspect of the ovary, and
forms with it and the broad ligament a pouch called the =bursa ovarica=.
The =uterine extremity= of the tube communicates with the cavity of the
cornu by a minute orifice, the =ostium uterinum=. The =ovarian= or
=fimbriated extremity= is expanded into a funnel-shaped =infundibulum=.
The margin of the latter is slit into irregular processes or =fimbriæ=,
some of which, the =fimbriæ ovaricæ=, are attached in the ovulation
fossa. In the center of the fimbriated extremity is a small opening, the
=ostium abdominale=, by which the tube communicates with the peritoneal
cavity. The tube appears normally to be applied to the ovary, so that
the extruded ova pass into it and are conveyed to the uterus.[151]
Pedunculated cysts, the hydatids of =Morgagni=, are often found on one
or more of the fimbriæ. In the mesosalpinx are blind flexuous tubules,
which constitute the =paroöphoron=, a remnant of the Wolffian body.
They are most evident in the young adult, and tend to disappear with
increasing age. Not uncommonly they give rise to cysts.
=Structure.=—The tube is covered externally by a =serous coat= formed by
the mesosalpinx. The serous membrane is continued on the fimbriæ, and
meets the mucous lining on them. The =fibrous coat= or adventitia is
continuous with the fibrous lamina of the broad ligament. The =muscular
coat= consists chiefly of circular fibers, although longitudinal fibers
occur externally. The =mucous coat= is thin and is much plicated. The
folds (Plicæ tubariæ) are chiefly longitudinal, but in the wide part of
the tube (Ampullæ tubæ) they are very complex, so that on cross-sections
the spaces between the folds may be mistaken for branched tubular
glands. The folds are continued on to the fimbriæ. The =epithelium= is a
single layer of columnar ciliated cells, the cilia producing a current
directed toward the uterus. At the fimbriated extremity this epithelium
passes gradually into the squamous type of the serous coat.
=Vessels and Nerves.=—The =arteries= are derived from the =utero-ovarian
artery=. The =veins= are satellites of the arteries. The =lymphatics=
pass with the ovarian vessels to the lumbar glands. The nerves have a
similar origin to those of the ovary.