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ich completely surrounds each tubule and blood vessel, and binds it to its . It has been found possible to obtain an accurate idea of the arrangement of ctive tissue by submitting thin sections of the kidney to the action of certain luids. When this is done the tubules and blood-vessels are removed, and the

tissue stroma is left behind. The connective tissue thus revealed is seen to ntinuous network, the spaces in which faithfully reproduce the outlines and ement of the kidney tubules. The network of the stroma is continuous with of the kidney. Is of the Kidney.—The renal artery comes directly from the aorta, and is in proportion to the size of the organ to which it conveys blood. Its main is they approach the kidney to enter the hilum, lie between the tributaries of vein in front and the ureter behind. Within the sinus of the kidney the f the renal artery become arranged in a dorsal and a ventral group, the dorsal ng behind, the ventral ones in front of the subdivisions of the ureter. The oup of vessels supplies the part of the kidney which forms the anterior and Is of the sinus; the distribution of the dorsal group is for the most part to the portion of the kidney which lies behind, and to the medial side of ig the substance of the kidney in the manner described above (p. 1265), the larger in the intervals between the pyramids, and are called the arteriæ interlobares iterlobar arteries. These vessels dividing, form a series of incomplete arterial

arteriæ arciformes, which pass across the bases of the pyramids. Although of arterial arches, it must be understood that no anastomosis between the of the interlobar arteries actually takes place, but that each artery which

wall of the kidney sinus has an isolated distribution and possesses the of an “end artery. Each arterial arch gives off a number of vessels which gh the convoluted part of the cortex towards the surface of the kidney. These as the arteriæ interlobulares, and lie at very regular intervals. From them a short branches arise, termed vasa afferentia, each of which proceeds to the remity, or capsule, of a uriniferous tubule. Here the vas afferens breaks up h convoluted capillary mass, called a glomerulus, which is contained within the n of the capsule. The little vein which issues from the glomerulus, or vas stead of running directly into a larger vein, breaks up, after the manner of into capillaries which supply the tubules of the convoluted and radiate parts ney cortex. Hence almost all the blood which supplies the tubules of the t of the kidney passes in the first instance through the glomeruli. The tubules s of the pyramids also receive their blood-supply through vasa efferentia derived lomeruli which lie near. The little vessels passing from these glomeruli break endles of fine arteries, which give the bases of the pyramids their coarsely pearance. They are known as arteriolæ rectæ, and, like the arteriæ interre very conspicuous in injected preparations of the kidney. rous capsule of the kidney receives minute branches from the interlobular ne of which, piercing the capsule, communicate by capillaries with the vessels of adiposa. orresponding to the interlobular arteries and arteriolæ rectæ collect the blood pillaries surrounding the tubules, and unite to form a series of complete arches bases of the pyramids. From these venous arcades vessels arise, which traverse Is between the pyramids and reach the sinus of the kidney, where they unite

dorsal and ventral tributaries of the renal vein. Some small veins in the art of the cortex communicate through the fibrous capsule with minute veins ula adiposa. Issuing from the kidney sinus, the veins run a direct course to inferior vena cava. s of the Kidney.- The nerves of the kidney accompany the branches of the

are derived from the renal plexus. Their minute branches form regular xuses on the walls of the fine arteries and kidney tubules, and the presence of inations occurring among the epithelial cells lining the tubules has within s been demonstrated. inical evidence it would appear that the nerve fibres which supply the kidney 3 of the tenth, eleventh, and twelfth thoracic nerves. ns.-A marked difference in the size of the two kidneys is sometimes observed, ey on one side of the body being usually compensated for by a large kidney on the 2.

Cases of complete absence of one or other kidney are recorded. ses are on record in which an extra kidney was found on the right or left side.

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Traces of the superficial lobulation of the kidney, present in the fætus and young child, are often retained in the adult.

Horse-shoe kidney is not an infrequent abnormality. In these cases the two kidneys are united at their inferior ends, across the median plane, by a connecting piece of kidney substance The amount of fusion between the two kidneys varies much; it is sometimes very complete

, while in other cases it is but slight, the connexion being chiefly composed of fibrous tissue.

In very rare cases the kidney appears to be almost entirely surrounded by peritoneum and to be attached to the abdominal wall by a kind of mesentery, enclosing the vessels and nerves passing to the hilus. The condition is believed to be congenital.

Not very infrequently one or both kidneys are found at a much lower level than usual, and occupying a position in the iliac fossa or the pelvic cavity. This condition, when congenital, i associated with an arrest in the normal change in position, relative to surrounding structures, which the kidney experiences during development. In such cases the kidney does no receive its blood-supply from usually placed renal arteries, but from vessels which arise from the lower end of the aorta, or from the iliac, or the middle sacral artery. These con genitalls abnormally situated kidneys do not usually possess the typical outline of the normal organ, but vary much in shape, and the hilum is often directed downwards or backwards, and not medially

. In some mammalian animals, such as the bear, the ox, the porpoise, etc., the kidneys are composed of a number of completely isolated lobes, each of which corresponds to one pa pilla, its pyramids and surrounding cortex; while in others, such as the horse, the fusion of the lobes is more complete even than in the human kidney, and a single mass represents the united papillu

THE DUCT OF THE KIDNEY. The duct of the kidney is called the ureter, and begins above in a thin-walled funnel-shaped expansion called the pelvis renalis, which is placed partly within and partly outside the sinus of the kidney. Towards the level of the inferior end of the kidney the part of the pelvis which lies outside the sinus diminishes in calibre, and forms a tube-like duct, the ureter, which conveys the urine to the bladder.

Pelvis of the Kidney.-Within the sinus of the kidney the pelvis lies among the larger renal vessels. It is formed by the junction of two, or more rarely three thin-walled tubes, the calyces majores, each of which has a number of branches These latter, called calyces renales minores, are short, and increase in dia ineter as they approach the sinus wall, to which they are attached. Their wide, somewhat funnel-like ends enclose the renal papillæ, and receive the urine, which enters them through the foramina papillaria. The calyces are usually about eight in number

. one calyx sometimes surrounding two or even three papillæ. The portion of

the pelvis that lies outside the kidney has in front of it, in addition to the renal vessels, on the right side, the descending part of the duodenum, and on the left sile. a part of the pancreas and sometimes the duodeno-jejunal flexure (Fig. 979).

Ureter.-The ureter is the vessel which carries the urine from the pelvis of the kidney to the bladder. It is a pale-coloured thick-walled duct with a small lumen While in situ it has a total length of about ten inches, and lies throughout its closely connected. In its superior part the ureter lies in the abdominal cavity, and in its inferior part in the pelvis minor (Figs. 983 and 988).

The normal ureter, in the flaccid condition, measures after its removal from the bod y eleven to fourteen inches.

The pars abdominalis, or abdominal portion of the ureter, about five or five and a half inches in length, is directed downwards and slightly medially, and lies up the psoas major muscle. Certain structures are related to the ureters in a manner on each side of the body; for instance, the abdominal portion of each urete is crossed very obliquely, on its anterior aspect, by the internal spermatic and behind each ureter the genito-femoral nerve passes downwards and la (Fig. 983). Other structures are related to the duct of the right or left alone; on the right side, the descending part of the duodenum lies in front of the upper part of the ureter, and the line of attachment of the mesentery crosses i down, just before the ureter enters the cavity of the pelvis minor. On the side the line of attachment of the mesentery of the pelvic colon crosses the urete!

Crossing the common iliac, or the external iliac artery, the ureter enters pelvis minor. The left ureter usually crosses the common iliac artery, and the

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i most cases, lies across the external iliac; but this arrangement is by no
instant. The course and position occupied by the abdominal portion of
r is well seen in Fig. 983.
ay photographs, the shadow cast by the abdominal portion of the ureter when the
been rendered opaque, is seen to fall immediately in front of the tips of the transverse
f the lower lumbar vertebra.
ars pelvina or pelvis minor portion of the ureter is about four and a half or
:s in length; it passes downwards on the side wall of the pelvis, immedi-
ind the peritoneum, describing a curve which is convex backwards and
(Fig. 988). The most convex portion of this curve lies close to the deepest
e greater sciatic
g. 988). As it
upon the side
the pelvis the
rms the pos-

- Pyramid
indary of the
district known

Cortical substance arator triangle. c limit of this

--Papilla formed by the ferens, and the

Basal part of
pyramid

Pelvis nd anterior by the external sels and the Interlobar

+-- Renal artery artery n (Fig. 988). course within S minor the

Calyx in front of the c artery, and medial aspect turator nerve s and of the u mbilical

- Ureter bout the level ial spine, the crossed from Columna renalis of cortex cwards by the

Pars radiata of cortex eferens, and point onwards Fig. 987.—LONGITUDINAL SECTION OF THE KIDNEY, OPENING UP THE KIDNEY

SINUS. intimately reperitoneum. The pelvis of the kidney and some of its calyces have been laid open as they

lie within the sinus. bends

someally and forwards, to reach the posterior angle of the bladder, and

relationship with the upper end of the vesicula seminalis, in front it lies. The ductus deferens having crossed the ureter also turns nd as it does so it lies at a higher level and on a posterior plane to the e inferior end of the ureter is surrounded by a dense plexus of veins which vesical plexus into communication with the hypogastric vein. The great which connects the hypogastric plexus with the pelvic plexus, also relationship with the lower part of the pelvic portion of the ureter, n where the latter is crossed by the ductus deferens (Fig. 988). he right and left ureters reach the bladder they are a little more than apart. They pierce the bladder wall very obliquely, and are embedded muscular tissue for nearly three-quarters of an inch of their length. ey open into the bladder by two small slit-like apertures which are ar nature, and prevent a backward passage of fluid from the bladder. able, however, that an exaggerated idea of the valvular nature of gs of the ureters into the bladder is obtained by an examination s in the dead subject. When the bladder is empty the openings of

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the ureters are placed about one inch apart, but when that viscus is distended they are often two inches, or more, distant from one another. As the ureter pierces the bladder wall the muscular fibres of the bladder and ureter remain quite distinct, and so the ureter, remaining a thick-walled tubular structure, appears to pass through a gap in the muscular wall of the bladder. The mucous coat alone of the ureter becomes continuous with that of the bladder.

The canal of the ureter is not uniform throughout, but is somewhat constricted in certain places, corresponding to the regions where the ureter is most sharply curved or changes its direction. These more constricted parts of the tube are described as occurring one in the middle of the abdominal portion, one at

Branches of hypogastric artery Right ureter
Obturator artery

Nerve cord from hypogastric plexus

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Sacro-genital fold
Obliterated umbilical
artery (lig. umbilicale)
Plica vesicalis transversa

Vesical arteries

Ductus deferen's Paravesical peritoneal fossa

FIG. 988.-MEDIAN SECTION OF AN ADULT MALE Pelvis.
The coils of the small intestine and of the colon which lay within the pelvis have been lifted out in order to

give a view of the side wall of the pelvic cavity.

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junction of the abdominal and pelvic portions, and one in the pelvic part
ureter. Also just before the ureter joins the pelvis of the kidney and just
reaches the bladder wall its lumen is usually somewhat constricted.
broad ligament of the uterus, and lies to the lateral side of the cervix uteri and the

In the female, the ureter, near its termination, passes beneath the lower part of the upper part of the lateral wall of the vagina. It is accompanied in the inferior part its course by the uterine artery, which crosses it on its anterior aspect not far from its termination (Fig. 1002). Higher up it lies in the peritoneal ridge which forms the posterior boundary of the fossa ovarica, a posterior subdivision of the obturato fossa (Fig. 1002).

STRUCTURE OF THE URETER. The wall of the ureter, which is thick and of a whitish colour, is composed mucous, muscular, and fibrous coats. The tunica mucoså or mucous coat possesses al epithelium composed of many layers of cells, those nearest the surface being

The vesica e anterior part amant of the re in the termina

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ze. When the canal is empty the mucous coat is thrown into numerous dinal folds, and so its lumen exhibits a stellate outline in transverse section. omucous tissue varies much in thickness in different parts of the ureter, tains some elastic fibres. The unstriated muscle fibres which compose the ruscularis or muscular coat are collected into bundles which are separated by erable amount of connective tissue, and are arranged, some longitudinally, -rcularly. In the upper part of the ureter a relatively large amount

ective tissue is present deep to and among the bundles of muscle hich are arranged in three distinct strata-an inner longitudinal, an liate circular, and an outer longitudinal. In the middle part of the he same layers may be recognised, but the circularly disposed bundles of e more numerous than higher up. In the lower part of the ureter the ve tissue is relatively scanty and the inner longitudinal fibres lie close to g epithelium; in this region also the longitudinal folds of the mucous ome fewer and less marked. A short distance above the point where it the bladder, the wall of the ureter becomes much thickened by the

of a number of coarse bundles of longitudinally arranged muscle nich are applied to the outer surface of the muscular coat. These muscle m the so-called “sheath of the ureter,” and are continued on the superect of the vessel as it passes through the bladder wall. In the portion of r which traverses the wall of the bladder (pars intramuralis) nearly all s of the muscular coat are disposed longitudinally, i.e., in a direction o that of the vessel. The muscle fibres lie close beneath the epithelium, ust where the mucous coats of the bladder and ureter become continuous. ca adventitia or outer fibrous coat of the ureter varies in thickness at levels, and in its lower part blends with the connective tissue which lies e muscle fibres forming the sheath of the ureter just mentioned. aucous membrane of the calyces and of the pelvis of the kidney possesses an

resembling that of the ureter. Where each renal papilla projects into e calyces a deep circular recess, or fornix, is formed between the wall of

and the sloping side of the papilla ; at the bottom of this recess the 1 of the calyx becomes continuous with that covering the papilla. At Lina papillaria the epithelium joins that of the kidney tubules. The ibres in the wall of the calyces and of the pelvis are collected into loosely bundles separated by wide intervals occupied by fibrous connective tissue.

ureter, the outermost and innermost fibres run in a longitudinal, the te ones in a circular direction. The circularly arranged fibres alone tinct layer. s and Nerves of the Ureter.—The abdominal part of the ureter receives upply from the renal and internal spermatic arteries; the pelvic portion

by the superior vesical and middle hæmorrhoidal vessels. rves of the ureter reach it through the renal, the spermatic, and the c, plexuses. ns.—The ureter is sometimes represented by two tubes in its upper portion.

In rarer puble throughout the greater part of its extent, or even in its whole length from the kidney to the bladder. In such cases there may be two openings into the bladder. as regards such abnormalities is very common. s in the form of the pelvis of the kidney are of frequent occurrence. Most usually vides into two large subdivisions, one of which passes in the direction of the upper, that of the lower pole of the kidney. In some cases these branches come off directly ter without the intervention of a pelvis, or a marked subdivision may lead to the two pelves.

VESICA URINARIA. sica urinaria or urinary bladder is a hollow muscular organ situated in · part of the pelvic cavity, above and behind the symphysis pubis. It lies the rectum, from which it is separated in the male by the seminal vesicles minal portions of the ductus deferentes, and in the female by the vagina

The ureters, which convey the fluid secreted by the kidneys, open into the bladder about half an inch from the median plane.

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