364
UNIT 3
Organ Systems
Figure 18-18A.
Ductus deferens, spermatic cord.
H&E,
3
11
The
ductus deferens (vas deferens)
consists of bilateral tubes
that continue from the tails of the left and right
ductus
epididymis
. Each tube is about 30 to 40 cm long and is
surrounded by a thick wall of smooth muscle. Each ductus
deferens resides within a
spermatic cord
in its course from
the testis through the abdominal wall to the penis. The distal
portion of the ductus deferens becomes enlarged and is called
the
ampulla
(Fig. 18-18B). The spermatic cord contains the
ductus
deferens
,
testicular artery
,
pampiniform venous plexus
,
nerves
, and
lymphatic vessels
within the connective tissue.
Pampiniform venous
Pampiniform venous
plexus
plexus
Pampiniform venous
plexus
Ductus
Ductus
deferens
deferens
Ductus
deferens
Testicular arteries
Testicular arteries
Testicular arteries
A
Epithelium
Epithelium
Epithelium
Folds (mucosa)
Folds (mucosa)
Folds (mucosa)
Lamina propria
Lamina propria
Lamina propria
Lamina propria
Lamina propria
Lamina propria
Outer longitudinal
Outer longitudinal
muscle
muscle
Outer longitudinal
muscle
Inner longitudinal
Inner longitudinal
muscle
muscle
Inner longitudinal
muscle
Middle circular
Middle circular
muscle
muscle
Middle circular
muscle
B
Spermatozoa
Spermatozoa
Spermatozoa
Spermatozoa
Spermatozoa
Spermatozoa
Lumen
Lumen
Lumen
Epithelium
Epithelium
Epithelium
L
a
m
in
i
n
a
p
p
r
o
p
r
ia
i
a
Lamina propria
S
m
o
o
th
t
h
m
m
u
scle
s
c
l
e
Smooth muscle
C
Figure 18-18B.
Ductus deferens.
H&E,
3
69;
inset
3
476
The lining of the
ductus deferens
, like that of the
epididymis, is pseudostrati± ed columnar epithe-
lium. The ductus deferens is characterized by ± n-
gerlike mucosal folds extending into the lumen.
The thick muscularis contains inner longitudinal
muscle, middle circular muscle, and outer lon-
gitudinal muscle, although these muscle layers
are not easy to distinguish from one another.
The outer longitudinal muscle is covered by
an adventitia (connective tissue layer). The
smooth muscle of the ductus deferens is richly
innervated by postganglionic sympathetic nerve
± bers, which initiate ejaculation when activated.
The
inset
shows pseudostrati± ed columnar epi-
thelium with stereocilia of the ductus deferens.
The spermatic cord is a very long vascular strand containing
the testicular vessels that provide the blood supply to the
testis. If
testicular torsion
(twisted spermatic cord) occurs,
acute testicular pain and necrosis of testis tissue may result
because of interrupted blood supply from arteries or, more
commonly, because of venous infarction.
A
vasectomy (deferentectomy)
is a surgical
procedure for sterilization of the male. In this
minor surgical procedure, both sides of the
proximal portion of the ductus deferens are
typically severed and sealed. The procedure
prevents sperm from entering the urethra of
the penis.
Figure 18-18C.
Ductus deferens.
van Gieson
stain,
3
139; inset
3
476
An example of the
ductus deferens
with van
Gieson stain is shown. The nuclei of the sper-
matozoa are brownish to black and are located
in the lumen of the ductus deferens. Smooth
muscle lies beneath the lamina propria.
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