« PrécédentContinuer »
Beyond the ureter the duct takes a somewhat sudden bend, and passes downwards and medially towards the median plane, beneath the peritoneum of the pelvic floor. Reaching the interval between the base of the bladder in front and the rectum behind, the ducts of opposite sides occupy the angle formed between the vesiculæ seminales (Fig. 1012). As they approach one another each duct becomes somewhat tortuous, sacculated, and dilated, and assumes a general resemblance in structure to a portion of the seminal vesicle. This dilated part of the ductus deferens is termed the ampulla ductus deferentis. As it turns medially the duct lies a short distance behind the ureter, and immediately in front of the free edge of the peritoneal fold (sacro-genital) which bounds the recto-vesical or recto-genital pouch of the peritoneum. Just above the base of the prostate the ductus deferens becomes once more a narrow canal, and in this position it is joined by the duct of the corresponding seminal vesicle to form the ductus ejaculatorius, which, after a short course downwards, forwards, and medially through the prostate, opens into the urethra.
In some cases the ductus deferens crosses the obliterated umbilical artery before it enters the cavity of the pelvis minor; it normally does so in the fœtus.
A and B. Drawings illustrating the seminal vesicle and the ampulla of the ductus deferens taken from two different subjects.
C. The seminal vesicle and ductus deferens have been cut into to show the pitted structure of their walls.
Ductus Ejaculatorius (O.T. common ejaculatory duct).-The ejaculatory duct is a very slender canal, formed by the union of the ductus deferens with the duct of the corresponding seminal vesicle. It is less than one inch in length, and lies very close to its fellow of the opposite side as it passes through the prostate behind its median lobe. The ducts open by slit-like apertures into the first part of the urethra, one on each side of the utriculus prostaticus. They are well seen in sections through the upper part of the prostate (Fig. 1011).
The mucous membrane of the duct is thrown into numerous complicated folds, and in connexion with it are a number of remarkable minute diverticula, which are enclosed within the muscular coat of the duct.
Vesiculæ Seminales. The seminal vesicles are a pair of hollow sacculated structures placed in front of the rectum and behind the bladder (Fig. 1012). Each vesicle is usually about two inches in length, and has its long axis directed downwards, medially, and somewhat forwards. The superior extremity of the vesicle, which is partly covered by peritoneum, is large and rounded, and lies at a considerable distance from the median plane, behind the inferior end of the ureter. The peritoneum of the recto-vesical or recto-genital pouch separates the upper end of the seminal vesicle from the rectum; below the peritoneal cavity the vesicle
and rectum are more intimately related. The vesicle tapers towards its inferior end, which is placed close to the median plane and immediately above the prostate. Inferiorly, the vesicle be
comes constricted to form a short duct, the ductus excretorius, which joins the lateral side of the corresponding ductus deferens at an acute angle to form the ejaculatory duct. The medial side of each vesicle is related to the ductus = deferens, and the lateral
side, when the bladder is empty, lies close to the sloping pelvic floor. The seminal vesicle often. assumes a more vertical
Internal urethral orifice -Trigonun vesica
position when the bladder is FIG. 1011. distended; a more horizontal
direction when the bladder is empty. Its superior end
From a specimen in the Surgical Museum, Trinity College, Dublin.
is sometimes found to be curved backwards against the side of the rectum.
FIG. 1012.-DISSECTION TO DISPLAY THE POSTERIOR ASPECT OF THE VESICULE SEMINALES, THE AMPULLE OF THE DUCTUS DEFERENTES, AND THE PROSTATE. The coccyx and portions of the levatores ani have been removed, also a considerable portion of the rectum.
some cases the seminal vesicles are much smaller than usual, and may be less than one inch in length. Frequently they are asymmetrical as regards size and
THE MALE REPRODUCTIVE ORGANS.
We have here to describe (1) the testes or essential reproductive glands of the male, together with their (2) coverings and (3) ducts, (4) the prostate, (5) the bulle urethral glands, (6) the external genital organs, and (7) the male urethra.
The reproductive glands of the male, or testes, are a pair of nearly symmetrical oval-shaped bodies situated in the scrotum. The duct of each gland, at first, much twisted and intertwined, forms a structure known as the epididymis, which is applied against the posterior and lateral part of the testis. From the epididymis the excretory duct, or ductus deferens, passes upwards towards the inferior part of the anterior abdominal wall, which it pierces very obliquely, to enter the abdominal cavity. Here each ductus deferens is covered by the peritoneum, and almost at once crossing the pelvic brim, enters the pelvis. The duct now runs of the side wall of the pelvis towards the base of the bladder, where it comes inte relation with a branched tubular structure termed the vesicula seminalis. Joine by the duct of the vesicula seminalis, the ductus deferens forms a short cana called the ejaculatory duct, which terminates by opening into the prostatic part of the urethra. The prostate, a partly glandular, partly muscular structure surrounding the first part of the urethra, and also a pair of small glandular bodies called the bulbo-urethral glands, are accessory organs connected with the male
epididymis Appendix of testis
ducts of the bulbo-urethral glands and those of the prostate, like the ejaculatory ducts, open into the urethra, which thus serves not only as a pas sage for urine, but also for the generative products. The external genitals are the penis and
The male reproductive vaginalis glands, the testes, are a pair o somewhat oval, slightly flattened bodies of a whitish colour, measuring about an inch and s half in length, one inch from before backwards, and rather less in thickness. Each testis is placed within the cavity the scrotum in such a manne that its long axis is directed upwards, slightly forwards, and laterally, and usually the left gland occupies a lower level than the right. The testis (Fig. 1003) has two somewhat flattened surfaces, one of which called the facies lateralis, or lateral surface, looks backwards as well as laterally; the other, the facies medialis or medial surface, looks forwards as well as medially, and is usually the more flattened. The two surfaces are separated by two rounded borders, one of which the margo anterior, is the more convex and free; while the other, the margo posterior is less rounded, and by it the organ is suspended within the scrotum. The epididymis and the lowest portion of the funiculus spermaticus, or spermatic cord, ar
FIG. 1003. RIGHT TESTIS AND EPIDIDYMIS, EXPOSED BY THE
attached to the posterior border of the testis. Each border ends above in the superior extremity, and below in the inferior extremity of the testis. Owing to an obliquity of the long axis of the gland, the superior extremity of the testis lies on a more anterior and lateral plane than the inferior extremity.
Epididymis. The epididymis is a somewhat crescentic structure, which is curved round the posterior border of the testis and overlaps to some extent the posterior part of the lateral surface of that organ. The superior, somewhat swollen part of the epididymis, is called the caput epididymidis or head, and overhangs the superior end of the testis, to which it is directly connected by numerous emerging ducts, by -connective tissue, and by the serous covering of the organ. The inferior and smaller end is termed the cauda epididymidis or tail, and is attached by loose areolar tissue and by the serous covering to the inferior end of the testis. The intermediate part, the body, or corpus epididymidis, is applied against, but is separated from, the posterior part of the lateral surface of the testis by an involution of the serous covering of the organ, which forms an intervening pocket termed the sinus epididymidis (O.T. digital fossa).
The main mass of the epididymis is composed of an irregularly twisted canal, the ductus epididymidis, which forms the first part of the duct of the testis.
Minute sessile, or pedunculated, bodies are often found attached to the head of the epididymis or to the superior end of the testis. These are called appendices of the epididymis and testis (O.T. hydatids of Morgagni), and have a developmental interest. The minute body which lies on the superior end of the testis represents the free end of Müller's duct in the embryo and the fimbriated end of the uterine tube of the female; it is usually sessile. Above the head of the epididymis, and in front of the lower part of the spermatic cord, there may also be present a small rudimentary body called the paradidymis. This is rarely seen in the adult, and is best marked in young children.
Tunica Vaginalis.-The cavity within which the testis and epididymis are placed is lined by a smooth serous membrane-the tunica vaginalis-which resembles in appearance and structure the peritoneum, from which it is originally derived. The cavity is considerably larger than the contained structures, and extends not only down to a lower level than the testis, but also reaches upwards to a higher level than the gland. The sac, or cavity, tapers as it is traced upwards, and above the level of the testis the funiculus spermaticus or spermatic cord bulges forwards into its posterior part. The tunica vaginalis lines the cavity for the testis, and is reflected from the posterior wall of the scrotal chamber over the testis and epididymis, giving a covering to each. The part of the membrane lining the cavity is called the lamina parietalis or parietal portion of the tunica vaginalis, while the part clothing the testis and epididymis i termed the lamina visceralis or visc portion. Between the lateral st sur of the testis and the body of epididymis, the visceral part of interval called the sinus epididym is limited above and below by s pass from the testis to the head of as the superior and inferior l surface of the testis receives I
where the globus major is attached, inferiorly where the cauda epididymidis is in contact, and posteriorly where the blood-vessels and nerves enter the organ from the funiculus spermaticus or spermatic cord.
Structure of the Testis and Epididymis.-Beneath the serous tunica vaginalis the testis is invested by an external coat, composed of dense white inelastic fibrous tissue called the tunica albuginea, from the deep surface of which a number of slender fibrous bands or septa dip into the gland. These the septula testis-imperfectly divide the organ into a number of wedge-shaped parts called lobuli testis (Fig. 1005). All the septa end posteriorly in a mass of fibrous tissue which is
directly continuous with the tunica albuginea, and which projects forwards into the testis along its posterior border. This structure receives the name of mediastinum testis, or corpus Highmori, and is traversed by an exceedingly complicated network of fine canals, into which the minute tubules which compose the substance proper of the testis open. The mediastinum is also pierced by the arteries, veins, and lymph vessels of the testis. These vessels enter the posterior border of the organ, and traversing the mediastinum, spread out on the fibrous septa which radiate towards all parts of the deep surface of the tunica albuginea. In this way a delicate network of vessels (tunica vasculosa) is formed on the deep surface of the tunica albuginea and on the sides of the septa. The mediastinum, the septa, and the tunica albuginea form a framework enclosing a number of imperfectly isolated spaces which are filled by a loosely packed substance of a light brown colour called the parenchyma testis.
Body of epididymis
The parenchyma is composed of enormous numbers of much-convoluted seminiferous tubules, called tubuli seminiferi contorti, and completely fills up the intervals between the septa. The minute tubules look like fine threads to the unaided eye. and are but loosely held together by a small amount of connective tissue. Usually three or four tubules are found in each lobule of the gland, and the total number in the testis has been estimated at about 600. The seminiferous tubules, after a course of about two feet in length, pass towards the mediastinum testis and unite at acute angles, to form a smaller number of slender tubes which run a straight These latter are called tubuli seminiferi recti, and open into a complicated network of fine canals situated in the substance of the mediastinum, called the rete testis. The tubules are much more twisted and convoluted in the cortical part the gland, near the tunica vaginalis, than in the region of the mediastinum, and often give off side branches which, according to some observers, may effect anastomoses between the tubules. It appears doubtful, however, if the seminiferous tubules of the testis do really anastomose.
Microscopic sections show that the walls of the seminiferous tubules are composed a basement membrane and of an epithelial lining, formed of several layers of cells. Certain cells of this epithelium are, in the adult, constantly undergoing transformation into spermatozoa, and the appearance of the tubules in section varies much, according to age and to the greater or less activity of the epithelial cells.
The secretion of the seminiferous tubules is carried through the tubuli seminiferi recti into the rete testis, and leaves the latter, to reach the canal of the epididymis, through from fifteen to twenty minute tubules called ductuli efferentes testis or efferent ductules. These latter pierce the tunica albuginea and enter the caput epididymidis where it is in direct contact with the superior extremity of the testis. Each efferent ductule is at first straight, but soon becomes much convoluted, and forms a little conical mass of twisted tubule, called