-Vein -`Wolffian-duct -- Intestine of numerous tubules which open into the Wolffian duct. This at first is an important excretory organ, but during development becomes used for other purposes. In the male, as has been shown, it may form the rete testis, and certainly forms the vasa efferentia and globus major of the epididymis: in addition to these, some of its separate tubes probably account for the vas aberrans and the organ of Giraldes (see fig. 8, E. and O.G.). In the female the tubules of the epodphoron represent the main part, Pronephros. Mesonephros. Metanephros. Bladder.
Cloaca.
Rectum.
Miillerian duct. Wolffian duct. Ureter.
Sessile hydatid. Pedunculated hydatid. Sexual gland.
Pro. N.
M.N.
Mt. N. B.
Clo.
M.D. W. D. Ur.
S.H.; P .H.
S. G.
inward to meet its fellow at the back of the bladder, just above the prostate. The whole length of the vas is 12 to 18 in. and it is remarkable for the great thickness of its muscular walls, which gives it the feeling of a piece of whipcord when rolled between the finger and thumb.
A little above the globus major a few scattered tubules are found in children in front of the cord; these form the rudimentary structure known as the organ of Giraldes or paradidymis. As the vas deferens approaches the prostate it enlarges and becomes slightly sacculated to act as a reservoir for the secretion of the testis; this part is the ampulla (see fig. 2).
Posterior superior iliac spine Ureter Great sciatic notch Vas deferens; Spine of ischium Vas deferens Seminal vesicle Bladder wall Levator ani Prostate 9, ? Ischio-rectal fossa Tuberosity of ischium Gluteus maximus The vesiculae seminales are sac-like diverticula, one on each side, from the lower part of the ampullae of the vasa deferentia. They are about 2 in. long and run outward behind the bladder and parallel to the upper margin of the prostate for some little distance, but usually turn upward near their blind extremity. When carefully dissected and unravelled each is found to consist of a thick tube, about 5 in. long, which is sharply bent upon itself two or three times, and also has several short, sac-like pouches or diverticula. The vesiculae seminales are muscular sacs with a mucous lining which is thrown into a series of delicate net-like folds. The convolutions are held together by the pelvic cellular tissue, and by involuntary muscle continuous with that of the bladder. It is probable that these vesicles are not reservoirs, as was at one time thought, but form some special secretion which mixes with that of the testes. Where the vesiculae join the ampullae of the vasa deferentia the ejaculatory ducts are formed; these are narrow and thin-walled, and run, side by side, through the prostate to open into the floor of the prostatic urethra.
The prostate is partly a muscular and partly a glandular structure, situated just below the bladder and traversed by the urethra; it is of a somewhat conical form with the base upward in contact with the bladder. Both vertically and transversely it measures about an inch and a quarter, while antero-posteriorly it is only about three-quarters of an inch, though its size is liable to great variation. It is enclosed in a fibrous capsule from which it is separated by the prostatic plexus of veins anteriorly. It is often described as formed of three lobes two lateral and a median or posterior, but careful sections and recent research throw doubt on the existence of the last.
Microscopically the prostate consists of masses of long, slender, slightly branching glands, embedded in unstriped muscle and fibrous tissue; these glands open by delicate ducts (about twenty in number) into the prostatic urethra, which will be.
described later. In the anterior part of the gland are seen bundles of striped muscle fibres, which are of interest when the comparative ana Ampulla of vas deferens tomy of the gland Cut end of great sacrois studied: they are 1 sciatic ligament Common ejaculatory duct Levator ani than in old prostates.
The male urethra begins at the bladder and runs through the prostate and perineum to the penis, which it traverses as far as the tip. It is divided into a prostatic, membranous and spongy part, and is altogether about 8 inches in length. The prostatic urethra runs downward through the prostate rather nearer the anterior than the pos terior part. It is about an inch and a quarter long, and in the middle of the gland it bends forward forming an angle (see fig. 5); here it is from a third to half an inch wide, though at the base and apex of the prostate it is narrower. When it is slit open from in front a longitudinal ridge is seen in its posterior wall, which is called the verumontanum or crista urethra, and on each side of this is a longitudinal depression, the prostatic sinus, into which numerous ducts of the prostate open, though some of them open on to the antero-lateral surface. Near the lower part of the verumontanum is a little pouch, the utriculus masculinus, about one-eighth of an inch deep, the opening of which is guarded by a delicate membranous circular fold, the male hymen. Close to the opening of the utriculus the ejaculatory ducts, already mentioned, open into the urethra by very small apertures. The part of the urethra above the openings of these ducts really belongs to the urinary system only, though it is convenient to describe it here. After leaving From A. F. Dixon, Cunningham's Text-book of Anatomy. FIG. 2. - View of the Base of the Bladder, Prostate, Seminal Vesicles and Vasa Deferentia from behind.
The coccyx and the sacro-sciatic ligaments, together with the muscles attached to them, have been removed. The levatores ani have been separated along the median raphe, and drawn outwards. A considerable portion of the rectum and the upper part of the right seminal vesicle have been taken away.
Posterior superior iliac spine Cut end of rectum Apex of sacrum Great sciatic notch Ureter Peritoneum Spine of ischium Bladder wall Seminal vesicle Tuberosity of ischium Ischio-rectal fossa Cut end of rectum External sphincter ani Gluteus maximus better seen in young the prostate the urethra runs more forward for about threequarters of an inch, lying between the two layers of the triangular From C. S. Wallace's Prostatic Enlargement. FIG. 4. - Transverse Section of a young Prostate, showing wavy striped muscle in front, urethra in the middle, and the two ejaculatory ducts behind.
(external meatus) a vertical slit. Into the whole length of the urethra mucous glands (glands of Littre) open, and in the roof of 1 Figs. 3, 4, 5 and 9 of this article are redrawn from Cuthbert S. Wallace's Prostatic Enlargement by permission of the managers of The Oxford Medical Publications.
the fossa navicularis the mouth of one of these is sometimes so large that it may engage the point of a small catheter and is known as the lacuna magna. As a rule the meatus is the narrowest part of the whole canal.
Opening into the spongy urethra where it passes through the bulb are the ducts of two small glands known as Cowper's glands, which lie on each side of the membranous urethra and are best seen in childhood.
The penis is the intromittent organ of generation, and is made up of three cylinders of erectile tissue, covered by skin and subcutaneous tissue without fat. In a transverse section two of these cylinders (the corpora cavernosa) are placed above, side by side, while one, the corpus spongiosum, is below. Posteriorly, at what is known as the root of the penis, the two corpora cavernosa diverge, become more and more fibrous in structure, and are attached on each side to the rami of the ischium, while the corpus spongiosum becomes more vascular and enlarges to form the bulb. It has already been pointed out that the whole length of the corpus spongiosum is traversed by the urethra. The anterior part of the penis is formed by the glans, a bell-shaped structure, apparently continuous with the corpus spongiosum, and having the conical ends of the corpora cavernosa fitted into depressions on its posterior surface. On the dorsum of the penis the rim of the bell-shaped glans projects beyond the level of the corpora cavernosa, and is From C. S. Wallace's Prostatie Enlargement. FIG. 5. - Sagittal Median Section of Bladder, Prostate and Rectum, showing one of the ejaculatory ducts.
known as the corona glandis. The skin of the penis forms a fold which covers the glans and is known as the prepuce or foreskin; when this is drawn back a median fold, the frenuluni praeputii, is seen running to just below the meatus. After forming the prepuce the skin is reflected over the .glans and here looks like mucbus membrane. The structure of the corpora cavernosa consists of a strong fibrous coat, the tunica albuginea, from the deep surface of which numerous fibrous trabeculae penetrate the interior and divide it into a number of spaces which are lined with endothelium and communicate with the veins. Between the two corpora cavernosa the sheath is not complete and, having a comb-like appearance, is known as the septum pectinatum. The structure of the corpus spongiosum and glans resembles that of the corpora cavernosa, but the trabeculae are finer and the network closer.
Female Reproductive Organs. The ovary is an organ which in shape and size somewhat resembles a large almond, though its appearance varies considerably in different individuals, and at different times of life. It lies in the side wall of the pelvis with its long axis nearly vertical and having its blunt end (tubal pole) upward. Its more pointed lower end iš attached to the uterus by the ligament of the ovary, while its anterior border has a short reflection of peritoneum, known as the mesovarium, running forward to the broad ligament of the uterus. It is through this anterior border that the vessels and nerves enter and leave the gland.
Under the microscope the ovary is seen to be covered by a FIG. 3. - Coronal Section through the Pelvis, showing the relations of the bladder above, prostate and bulb below.
ligament, both of which it pierces. This is known as the membranous urethra, and is very narrow, being gripped by the compressor urethrae muscle.
[HISTORY |
The spongy urethra is that part which is enclosed in the penis after piercing the anterior layer of the triangular ligament. At first it lies in the substance of the bulb and, later, of the corpus spongiosum, while finally it passes through the glans. In the greater part of its course it is a transverse slit, but in traversing the glans it enlarges considerably to form the fossa navicularis, and here, in transverse section, it looks like an inverted T (1), then an inverted Y (A), and finally at its opening '-'uNtAT and Adolf (1806-1871), and his grandsons Johann Adolf and Oskar Philipp.
J. G. Repsold introduced essential improvements in the meridian circles by substituting microscopes (on Jesse Ramsden's plan) for the verniers to read the circles, and by making the various parts perfectly symmetrical. For a number of years the firm furnished meridian circles to the observatories at Hamburg, Konigsberg, Pulkova, &c.; later on its activity declined, while Pistor and Martins of Berlin rose to eminence. But after the discontinuance of this firm that of Repsold again came to the front, not only in the construction of transit circles, but also of equatorial mountings and more especially of heliometers (see Micrometer) .
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