CHAPTER 18
Male Reproductive System
367
Figure 18-21A.
Seminal vesicles.
H&E,
3
11
The
seminal vesicles
are paired glands that develop from
the ductus deferens. Each seminal vesicle consists of a
single highly convoluted tube with a duct that connects to
the terminal portion (
ampulla
) of the
ductus deferens
. The
ampulla of the ductus deferens is continuous with the ejacu-
latory duct. The mucosa of the seminal vesicles is extensively
branched and folded and lined mostly by pseudostratiF ed
columnar epithelium. The epithelium is supported by a thin
layer of connective tissue (
lamina propria
), and beneath
it is the
muscularis
composed of
inner circular
and
outer
longitudinal smooth muscle
. Contraction of the muscularis
pushes the seminal secretion into the ejaculatory duct during
ejaculation.
Folded
Folded
mucosa
mucosa
Folded
mucosa
Lumen
Lumen
Lumen
Lumen
Lumen
Lumen
Muscularis
Muscularis
Muscularis
A
Epithelium
Epithelium
Epithelium
Lamina propria
Lamina propria
Lamina propria
Pseudostratified
Pseudostratified
columnar epithelium
columnar epithelium
Pseudostratified
columnar epithelium
Smooth
Smooth
muscle
muscle
Smooth
muscle
B
Epithelial
Epithelial
cell
cell
Epithelial
cell
Seminal
Seminal
fluid
fluid
Seminal
fluid
Blood
Blood
vessel
vessel
Blood
vessel
Seminal
Seminal
fluid
fluid
Seminal
fluid
Seminal
Seminal
fluid
fluid
Seminal
fluid
Mucosa
Mucosa
Mucosa
C
Figure 18-21B.
Seminal vesicle.
H&E,
3
278; inset
3
635
This is an example of the mucosa of the
seminal vesicle
. The
nonciliated
,
pseu-
dostrati±
ed columnar epithelium
(
inset
),
underlying
lamina propria
, and some
smooth muscle ±
bers
are shown here. The
epithelium of the seminal vesicle varies from
simple to pseudostratiF
ed columnar epithe-
lium. The mucosa appears branched and
folded. The epithelium contains basal cells
and secretory cells with abundant rough
endoplasmic reticulum and well-developed
Golgi
complexes.
Figure 18-21C.
Seminal vesicle with sem-
inal fl uid.
H&E,
3
139; inset
3
328
The
seminal vesicles
produce large volumes
of
seminal fl
uid
, which contributes about
70% of the volume of semen. Seminal fl
uid
contains
fructose
and other
sugars
,
prosta-
glandins
,
fl avins
,
phosphorylcholine
,
mucus
,
vitamin C
, and
proteins
. The
fructose
pro-
vides an energy source for sperm motility;
the
fl avins
, also known as
lipochrome pig-
ment
, add a yellowish color to the seminal
fl uid and have a strong fl uorescent quality
under the ultraviolet light. The
inset
shows
seminal epithelium and seminal fl uid (vis-
cous material) F
lling the lumen of a seminal
vesicle.
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