Page 310 - Veterinary Histology of Domestic Mammals and Birds, 5th Edition

292 Veterinary Histology of Domestic Mammals and Birds

tunica muscularis of the dog and tomcat consists mainly Pars glandularis of the ductus deferens
VetBooks.ir of inner circular and outer longitudinal layers. The lamina propria of the glandular portion of the ductus
deferens is densely packed with branched tubular glands.
The tunica muscularis is surrounded by a tunica adven-
titia or, within the peritoneal and pelvic cavities, a tunica The end pieces may have vesicular expansions.
serosa. The loose connective tissue of the tunica adventitia The pseudostratified columnar glandular epithelium
is extensively vascularised and rich in nerve plexuses. varies in height depending on the degree of secretory
activity. Release of the acidophilic secretion into the typi-
Ductus deferens of birds cally dilated glandular lumen is primarily by the apocrine
The ductus deferens of birds is lined by pseudostratified mode. The adluminal region of the wall of the glandular
epithelium with few stereocilia and secretory cells. Near portion of the ductus deferens may contain a mixture of
its opening into the cloaca, the ductus deferens straightens seminal plasma and spermatozoa. Recent findings suggest
to become the pars recta ductus deferentis. This straight that the ampulla of the ductus deferens may act as a stor-
portion is continued by the ampulliform receptaculum age area in which maturation processes occur at the cell
ductus deferentis. This structure is not homologous with membrane of the spermatozoa.
the ampulla ductus deferentis of mammals, as there are During ejaculation, the secretory product is released via
no secretory cells in its walls. The ductus deferens opens dilated collecting ducts into the ductus ejaculatorius (stal-
at the ostium ductus deferentis. The ostium is located on lion, bull) or the lumen of the ductus deferens (dog, boar).
the conical papilla ductus deferentis, which projects into In the bull, lipid droplets may be present in the basal cells
the lumen of the urodeum. of the epithelium. The glands are divided into lobules by
Within the wall of the urodeum, near the receptaculum, connective tissue septa containing numerous capillaries. In
there is an arterial network (rete mirabile arteriosum) the stallion and bull, the septa are reinforced by thin slips
arising from the pudendal artery. This is referred to as the of smooth muscle cells.
vascular body of the phallus (corpus vasculare phalli).
Vesicular glands (glandula vesicularis)
Accessory glands (glandulae genitales The paired vesicular glands are compound tubulo-alveo-
accessoriae) lar glands lined by pseudostratified columnar epithelium
The combined secretions of the accessory glands of the (Figures 13.27 and 13.28). The columnar cells vary in
male reproductive system constitute the seminal plasma. density, depending on the functional state of the gland.
Ejaculate is composed of seminal plasma and sperma- Modified microvilli are present on the surface. The cells
tozoa. The secretory activity of the accessory glands is are rich in organelles associated with secretory activity
controlled largely by the reproductive cycle, particularly in (endoplasmic reticulum, Golgi apparatus, peroxisomes).
non-domesticated animals with seasonal breeding cycles. Secretory product is released by the apocrine mode. The
The primary function of accessory glands is to produce epithelium contains solitary small, dark basal cells. Within
serous or mucous secretions that nourish, transport and acti- the glandular lobules, the tubular segments are expanded
vate spermatozoa, and to protect spermatozoa by neutralising to form reservoirs for glandular secretions. These por-
the acid urine. The accessory glands are comprised of the: tions, and the main excretory ducts, are lined by simple
cuboidal epithelium.
· terminal (glandular) portion of the deferent ducts, In the lamina propria, individual tubulo-alveolar units
· vesicular glands (glandula vesicularis), are interconnected by highly vascular loose connective tis-
· prostate gland (glandula prostatica) and sue. Dense collagenous septa divide the glandular tissue
· bulbourethral glands (glandula bulbourethralis). into lobules of varying size. The glands are surrounded
by a tunica muscularis composed of smooth muscle and a
Species variation tunica adventitia.
The vesicular glands produce a white to yellowish gel-
Horse, ox and pig: All accessory glands are present in
the stallion, bull and boar. The pars glandularis of the like secretion rich in fructose and citric acid. The alkaline
ductus deferens is ampulliform in the stallion and bull conditions produced by the secretion promote the motil-
(see above) (Figures 13.25 and 13.26). ity of spermatozoa, with fructose acting as an energy
source. Inositol and ergothioneine have been detected in
Carnivores: Vesicular glands are absent. vesicular gland secretions in boars. There is also evidence
Dog: The pars glandularis of the ductus deferens is that the vesicular glands synthesise prostaglandins.
ampulliform. There are no bulbourethral glands. The columnar epithelial cells are highly active
secretory cells. In addition to glycogen, they contain per-
Structural features of the accessory glands are summa- oxisomes and lipid droplets. Larger lipid droplets are seen
rised in Table 13.1. in basal cells (‘dwarf cells’). The lipid material consists of

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