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Urology
Urology is the science deals with diseases and
disorders of the male genitourinary tract and the
female urinary tract.
Surgical diseases of the adrenal gland are also
included.
Anatomy
The retroperitonial space
Lies on the posterior abdominal wall behind the
parietal peritoneum.
The floor of the space is formed by psoas, quadratus
lumborum & origin of transversus abdominis muscle .
Each of these muscle is covered by definite layer of
fascia & in front of the fascial layer variable amount
of fatty connective tissue that forms the bed of the
suprarenal gland ,the kidneys , the ascending &
descending parts of colon & the duodenum.
also contain the ureters &the renal &gonadal blood
vessel
Kidneys
The kidneys are reddish brown &lie behind the
peritoneum high up in the posterior abdominal wall
on the either side of the vertebral column.
The Rt. Kidney lie slightly lower than the Lt.
because of the large size of the liver.
On the medial concave part of the kidney lies the
hilum which transmit the renal veins, arteries &the
ureters. With lymph vessel &sympathetic fibers .
The kidneys have the following covers .
Fibrous capsule ,closely applied to the kidneys.
Perirenal fat ,covers the fibrous capsule.
Renal fascia ,condensation of connective tissue lies
outside the perirenal fat & encloses the kidneys &the
suprarenal gland .
Pararenal fat, lies external to the renal fascia &is
often large in quantity
Renal structure
Each kidney has dark brown outer cortex &
light brown inner medulla
The medulla is composed of about a dozen renal
pyramids ,each having its base oriented toward the
cortex & its apex ,
the renal papilla projecting medially .
the cortex extend into the medulla between adjacent
Pyramids as the renal columns.
The renal sinus is the space within the hilum contain
upper expand end of the ureter ,the renal pelvis ,this
divides into 2 or 3 major calyces
Each of which divides into 2 or 3 minor calyces
each minor calyces indented by the apex of renal
pyramid , the renal papilla .
Histology
The functioning unit of the kidney is the nephron,
which is composed of a tubule that has both
secretory and excretory functions.
The secretory portion is contained largely within the
cortex and consists of a renal corpuscle and the
secretory part of the renal tubule
The excretory portion of this duct lies in the medulla.
The renal corpuscle is composed of the vascular
glomerulus, which projects into
Bowman’s capsule, which, in turn, is continuous with
the epithelium of the proximal convoluted tubule.
The secretory portion is made up of the proximal
convoluted tubule, the loop of Henle, and the distal
convoluted tubule
The excretory portion is the collecting tubule, which
is continuous with the distal end of the ascending limb
of the convoluted tubule.
It empties its contents through the tip (papilla) of a
pyramid into a minor calyx.
Important relations of the Rt. Kidney
Anteriorly ;-the suprarenal gland ,the liver , the 2nd
part of the doudenum & the Rt colic flexure.
Posteriorly;-the diaphragm ,the 12th rib, & the psoas,
quadratus lumborum & the transversus abdominis
muscle .
important relations of the Lt. Kidney
Anteriorly ;- the suprarenal gland, the spleen, the
stomach ,the pancreas, the Lt. Colic flexure ,the coils
of the jejunum.
posteriorly;- the diaphragm, the costodiaphragmatic
recessof the pleura,the eleventh &12th rib, the psoas
,quadratus lumborum ,& transversus abdominis
muscles.
The subcostal iliohtpogastric &ilioinguinal nerves
run downward &laterally
Blood supply
Arteries
The renal artery arise from the aorta at the level of
the 2nd lumber vertebra .each renal artery usually
divides into 5 segmental arteries
That enter the hilum of the kidney between the renal
pelvis (posteriorly) & the renal vein. they are
distributed to different segments or areas of the
kidney.
Lobar arteries arise from each segmental artery ,one
for each renal pyramid.
each lobar artery gives off 2 or 3 interlobar arteries .
at the junction of the cortex & medulla the interlobar
arteries give off the Arcuate arteries ,which arch
over the bases of the pyramids .
the arcuate arteries give off several interlobular
arteries that ascend in the cortex .the afferent
glomerular arterioles arise as branches of the
Interlobular arteries .
Veins
The renal vein emerge from the hilum in front of the
renal artery &drains into the I.V.C
The left renal vein is about 3 times longer than the
right one
Lymph drainage
Lateral aortic lymph nodes around the origin of the
renal artery
Nerve supply
Renal sympathetic plexus .the afferent enter the
spinal cord in the
10th ,11th ,&12th thoracic nerves .
Ureter
The two ureters are muscular tubes that extend from
the kidneys to the posterior surface of the bladder ,
The urine is propelled along the ureter by peristaltic
contraction of the muscle coat .assisted by the
filtration pressure of the glomeruli .
Each ureter measures about 10 in.(25 cm) long &
resembles the esophagus in having 3 constrictions
along its course .
where the renal Pelvis join the uerter,
where its kinked as it cross the pelvic brim &
where it pierces the bladder wall .
The renal pelvis
is the funnel shaped expanded upper end of the ureter
It lies within the hilum of the kidney & receive the
major calyces .
The ureter emerges from the hilum of the kidney &
run vertically downward behind the parietal
peritoneum (adherent to it ) on the psoas muscle.
It enters the pelvis by crossing the bifurcation of the
common iliac artery,
Then runs down the lateral wall of the pelvis,to the
ischial spine turn forward to enter the lateral angle of
the bladder
Relations of the Rt. Ureter.
Anteriorly ;- the duodenum,the terminal part of the ileum ,the Rt. Colic
&ileocolic vessels ,the Rt.testicular or ovarian vessels ,&the root of the
Mesentery of the intestine .
Posteriorly;- The Rt, psoas muscle which separates it from the lumbar
Transverse process ,&the bifurcation of the Rt. common iliac artery .
Relations of the Lt. Ureter
Anteriorly;- the sigmoid colon &sigmoid mesocolon ,the Lt. Colic
vessels ,&the Lt. Testicular or ovarian vessels .
Posteriorly ;- the Lt. Psoas muscle ,which separates it form the lumbar
Transverse process ,& the bifurcation of the Lt. common iliac artery.
Blood supply
Arteries ;- the arterial supply to the ureter is as follow .
The renal artery
Upper end
Middle portion
The testicular or ovarian artery
In the pelvis
The superior vesical artery
Veins
Venous blood drains into the veins that correspond to the arteries .
Lymph drainage ;- to the lateral aortic &iliac nodes .
Nerve supply ;- renal, testicular (or ovarian), & hypogastric plexus
(in the pelvis). Afferent fibers travel with the sympathetic nerves
&enter the spinal cord in the 1st. &2nd. Spinal segments .
The urinary bladder
The urinary bladder situated immediately behind the
pubic bones within the pelvis . It is receptacle for the
storage of urine & in the adult has a maximum
capacity of about 500 ml.
The bladder has a strong muscular wall its shape &
relations vary according to the amount of urine that it
contains.
The empty bladder in the adult lies entirely within
the pelvis ;as the bladder fills, its superior wall rises
up into the hypogastric region.
.
The empty bladder is pyramidal having an apex ,a
base, & superior & 2 inferolateral surfaces ;it also
has a neck.
The apex of the bladder points anteriorly & lies
behind the upper margin of the symphysis pubis.
Its connected to the umbilicus by the median
umbilical ligament
The base, or posterior surface of the bladder ,faces
posteriorly & is triangular.
the superolateral angles are joined by the ureters ,&
the inferior angle give rise to the urethra.
the 2 vasa deferentia lie side by side on the posterior
surface of the bladder & separate the seminal vesicle
from each other.
the upper part of the posterior surface of the bladder
is covered by peritoneum, which forms the anterior
wall of the rectovesical pouch.
The lower part of the posterior surface is separated
from the rectum by the vasa deferentia, the seminal
vesicles,and the rectovesical fascia.
As the bladder fills ,the superior surface bulges
upward into the abdominal Cavity.
The peritoneal covering is peeled off the lower part of
anterior abdominal wall ,so that the bladder comes
into direct contact with the anterior abdominal wall.
The inferolateral surface are related in front to the
retropubic pad of fat & the pubic bones.
More posteriorly, they lie in contact with the
obturator internus muscle above & the levator ani
muscle below
.
THE NECK OF THE BLADDER lies inferiorly &
rests on the upper surface of the prostate ,here the
smooth muscle fibers of the bladder wall are
continuous with those of the prostate.
The neck of the bladder is held in position by the
PUBOPROSTATIC LIGAMENTS in the male &
PUBOVESICAL LIGAMENTS in the female.
These ligaments are thickening of the pelvic fascia.
The mucous membrane of the greater part of the
empty bladder is thrown into folds that disappear
when the bladder is full.
The area of the mucous membrane covering the
internal surface of the base of the bladder is referred
to as the TRIGONE.
Here, the mucous membrane is always smooth ,even
when the viscus is empty ,because the mucous
membrane over the trigone is firmly adherent to the
underlying muscular coat.
The superior angles of the of the trigone correspond
to the openings of the ureters , & the inferior angle to
the internal urethral orifice.
The ureters pierce the bladder wall obliquely,& this
provide valvelike action , which prevent reverse flow
of urine toward the kidneys as the
bladder fills.
the trigone is limited above by muscular ridge, which
runs from the opening of one ureter to that of the
other & is known as the interureteric ridge .
The muscular coat of the bladder is composed of
smooth muscle & is arranged in 3 layers of
interlacing bundles known as the detrusor muscle.
At the neck of the bladder ,the circular component of
the muscle coat is thickened to form the sphincter
vesicae.
Blood supply
Arteries ;the superior & inferior vesical arteries ,branches of
internal iliac arteries ,supply the bladder .
Veins ;The veins form the vesical venous plexus, which
communicates below with the prostatic plexus ; its
drained into the internal iliac vein.
Lymph drainage
The lymph vessels drain into the internal& external
iliac nodes.
Nerve supply
From the inferior hypogastric plexuses
The sympathetic postganglionic fibers originate in
the 1st &2nd lumber ganglia & descend to the bladder
via the hypogastric plexuses.
The parasympathetic preganglionic fibers arise as the
pelvic splanchnic nerves from the 2nd 3rd &4th sacral
nerves ,they pass through the inferior hypogastric
plexus to reach the bladder wall.
where they synapse with postganglionic neurons.
Most afferent sensory fibers arising in the bladder
reach the central nervous system via the pelvic
splanchnic nerves .some afferent fibers travel with
the sympathetic nerves via the hypogastric nerves &
enter the 1st & 2nd lumber segments of the spinal cord
.
The sympathetic nerves inhibit contraction of the
detrusor muscle of the bladder wall & stimulate
closure of the sphincter vesicae .
The parasympathetic nerves stimulate contraction of
the detrusor muscle of the bladder wall & inhibit
action of the sphincter vesicae.
Micturition
Micturition is a reflex action that is controlled by
higher centers in the brain.
The reflex is initiated when the volume of urine
reaches about 300 ml. Stretch receptors in the bladder
wall are stimulated & transmit impulses to the c.n.s.&
individual has a conscious desire to micturate.
Most afferent impulses pass up the pelvic splanchnic
nerves & enter the 2nd ,3rd &4th sacral segment of the
spinal cord.
Some afferent impulses travel with the sympathetic
nerves via the hypogastric plexus & enter the 1st &2nd
lumber segment of the spinal cord.
Efferent parasympathetic impulses leave the cord
from the 2nd ,3rd &4th sacral segment & pass via the
parasympathetic preganglionic nerve fibers
through the pelvic splanchnic nerves & the inferior
hypogastric plexus to the bladder wall where they
synapse with the postganglionic neurons.
By means of this nervous pathway ,the smooth
muscle of the bladder wall (the detrusor muscle ) is
made to contract ,& the sphincter vesicae is made to
relax.
Efferent impulses also pass to the urethral sphincter
via the pudendal nerve (S2,3&4), & is undergoes
relaxation.
Micturition can be assisted by contraction of the
abdominal muscles to raise the intra-abdominal &
pelvic pressure & exert external pressure on the
bladder .
In young children ,micturition is a simple reflex act
& takes place
whenever the bladder become distended.
In adult this reflex is inhibited by the activity of the
cerebral cortex until
the time & place for micturition are favorable .
Voluntary control of micturition is accomplished by
contracting the
Sphincter urethrae , assisted by the sphincter vesicae.
Control reflex normally developed during the 2nd or
3rd year of life .
Suprarenal glands
The 2 suprarenal glands are yellowish retroperitoneal
organs that lie on the upper pole of the kidneys. They
are surrounded by the renal fascia.
Separated from the kidneys by the perirenal fat.
Each gland has yellow cortex & dark brown medulla
The cortex ;- secretes hormones that include
1-mineralocorticoids, which Concerned with the
control of fluid & electrolyte balance.
2-glucocorticoids, which concerned with the control
of the metabolism of carbohydrates.
3-sex hormones, which may play role in the
prepubertal development of the sex organ.
The medulla ;- secretes the catecholamines
epinephrine & norepinephrine
.
The Rt. Suprarenal g
Is pyramid shaped &caps the upper pole of the Rt.
kidney.
It lies behind the Rt. lobe of the liver & extend
medially behind the I.v.c. it rests posteriorly on the
diaphragm.
The Lt. Suprarenal g.
Is crescentic in shape & extends along the medial
border of the Lt. kidney from the upper pole to the
hilus. It lies behind the pancreas and the lesser sac,
& the stomach & rests posteriorly on the diaphragm
nerve supply
preganglionic sympathetic derived from the
splanchnic nerve & supply most of the nerves end
in the medulla of the gland.
Blood supply
Arteries
are 3 in no. inferior phrenic , aorta, & renal arteries .
Veins
single vein emerge from each gland & drain into the
I.V.C. on the Rt. & into the renal vein on the Lt.
Lymph drainage ;- to lateral oartic nodes .