T E S T Í C U L O S
En la fase gestacional, los testículos descienden a la región escrotal a los 90 días en este período.
Se localizan en la zona perianal alta cerca del ano, su dirección es oblicua, cuando son machos jóvenes se sitúan más arriba hacia el ano y cuando son adultos se desplazan hacia abajo y son pendulantes.
La masa testicular determina la capacidad de producción espermática de los túbulos seminíferos y el peso de cada testículo en machos jóvenes es de 200 grs, mientras que en adultos llegan a pesar hasta 500 grs.
This tepidimys is tightly adhered to the outside of the testicle. The epididymis is highly coiled and when laid out end to end is over 189 ft in length.
The primary function of the epididymis is sperm maturation, transport and storage.
Spermatozoa entering the epididymis are neither motile nor fertile. It takes spermatozoa between 9
and 14 days to migrate from the head to the tail of the epididymis, the primary storage site. It has
been estimated that the tail of the epidiyimis contains about 75% of the total epididymal
spermatozoa. Spermatozoa become motile and acquire fertilizational competence in the body of the
epididymi due to the secretion of factors by the cells located in this region. Movement of
spermatozoa through the epididymi is thought to be due to the flow of rete fluid, the action of the
sterociliated epithelium and contractions of the circular muscle layer. Unejaculated spermatozoa are
gradually eliminated by excretion into the urine. Spermatozoa that are not excreted in the urine undergo a gradual aging process. During the aging process, fertilizational competence is lost first
and is followed by a decrease in motility. Eventually, dying spermatozoa
disintegrate. Ejaculates with dying spermatozoa often appear "clumpy", ie. - have large groups of
spermatozoa bound together by their heads.
The vas deferens is a thick, heavily
muscled tube through which sperm are transported from the tail of the epididymis to the pelvic
urethra, at which point the paired genital systems of the boar meet and converge with the urinary
tract just before the bladder. Adjacent to the pelvic urethra are three secondary sex glands: the
vesicular glands or seminal vesicles; the prostate gland; and the bulbo-urethral glands
El mediastino está constituído por un cordón de tejido fibroelástico a partir de la cual se irradian tabiques que dividen al parénquima en lóbulos. También existen otros tabiques a partir de la cara profunda de la albugínea.
