Download Anatomy of he Urinary System

Anatomy of he Urinary System
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The urinary system consists of
the following
Kidneys
Ureters
Urinary bladder
Urethra
The Kidney
• Bean-shaped organ
• It lies on the posterior
abdominal wall at the side of
vertebral column
• It measures 4x2x1 inches
• It has anterior and posterior
surfaces and medial and lateral
borders
• Right kidney is lower than the
left because of the liver
• The level of kidneys varies with
respiration of about 1 inch
The Kidney Cont.,
Renal hilum
• Is found at the medial concave surface
• Renal vein, renal artery and ureter are
found in the hilum in anterior posterior
order
• Lymphatics and sympathetic nerves pass
through the hilum
Renal sinus
All structures pass through the hilum in
addition to small amount of fat and the
pelvis are found in the sinus
• Suprarenal glands, kidneys,
and ureters and their vessels
are retroperitoneal structures
• Renal capsule formed of dense
connective tissue surrounding
the kidneys for support and
protection
• Perirenal fat a layer of fat
surrounds the kidney outside
the renal capsule
• Kidneys, suprarenal glands,
and perirenal fat are enclosed
by fascial membrane called
Renal fascia
• The two layers extend medially
to enclose the renal vessels
and blend with vascular fascia
• The two layers extend
inferiorly to enclose the
ureters as as Periuretric fascia
• A layer of fat surrounding the
kidneys, ureters, suprarenal
glands external to renal fascia
called Pararenal fat
• Perirenal fat, renal fascia,
pararenal fat and some
collagen fibers hold the
kidneys in fixed position
• Superiorly, renal fascia is
attached to inferior
diaphragmatic fascia
Internal structure of the Kidney
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Each kidney consists of:
Outer cortex
Inner medulla formed of
renal pyramids with apex
forming renal papilla
Cortex extends into
medulla as renal columns
Renal pelvis fills most of
the sinus
Major calyces
Minor calyces
Anterior relation of the Kidney
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Right kidney:
Suprarenal gland
Liver
Duodenum
Right colic flexure
Ileum
Left kidney
Suprarenal gland
Stomach
Spleen
Splenic artery
Pancreas
Jejunum
Left colic flexure
Anterior relation of the Kidney
Right Kidney
Left Kidney
Posterior Relation of the Kidney
• Diaphragm separates the
kidney from the pleural
cavity and 11th and 12th ribs
• Psoas major medially
• Quadratus lumborum in
the middle, transversus
abdominis laterally
• Subcostal, iliohypogastric
and ilioinguinal nerves
descend obliquely behind
the kidney
The Ureter
• It is a muscular organ
• Extends from renal pelvis in
abdomen, crosses the pelvic
brim at common iliac artery
bifurcation to the urinary
bladder
• It 10 inches in length
• On the back, extends along a
line from a point 5 cm from
spine of L1 to posterior
superior iliac spine
The Ureter Cont.,
• The abdominal part is retroperitoneal
• It runs close to the tips of transverse
processes of lumbar vertebrae as seen in
contrast radiographs
• It passes vertically on psoas muscle
• It enters the pelvis crossing the external
iliac artery
• It shows three constriction along its
course:
Between ureter and pelvis
At crossing the external iliac artery
At entrance to urinary bladder
• They are the sites of obstruction by renal
calculi
The Ureter Cont.,
• Ureter runs on the lateral part of
lesser pelvis
• It runs parallel to medial part of
greater sciatic notch
• At level of ischial spine, it turns
anteromedially to enter the
inferior surface of the bladder in
inferiomedial dirction
• The enterance is 5 cm a part on
external surface and 2.5 cm a
part at internal surface
• Oblique passage creates a
sphincter like structure at lower
end of ureter
Anterior Relation of the Ureter
Duodenum
Terminal Ileum
Left gonadal vessels
Right gonadal vessels
Left colic vessels
Right colic vessels
Sigmoid colon and
mesocolon
Ileocolic vessels
The Urinary Bladder
• It is a hollow muscular organ
• It is a pelvic organ after puberty
• It lies behind and superior to pubic
bones leaving retropubic space in
between
• It is divided into apex, fundus and
body
• It has 4 surfaces, superior,
posterior (base) and two
inferiolateral
• It is freely movable except at the
neck that is attached by lateral
ligaments of bladder and
puboprostatic ligament in male and
pubovesical ligament in female
Body
Apex
Fundus
The Urinary Bladder Cont.,
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Posterior relation in male:
Vas deferens
Seminal vesicle
Rectum
Rectovesical fascia
Peritoneum
Posterior relation in female:
Vagina and part of uterus
Superior relation in male:
Peritoneum
Coils of ileum
Sigmoid colon
Superior relation in female:
Uterus
Lateral relation
Obturator internus muscle
Levator ani muscle
The Urinary Bladder Cont.,
Anterior relation
• Symphysis pubis
• Retropubic fat
Inferior relation:
• Prostate gland
• The muscle of the bladder wall is
called Detrusor muscle
• It is thickened at the neck to
form involuntary internal
urethral sphincter
• Trigone is triangular area where
the two ureters and urethra
open into its angles
Blood Supply of the Urinary System
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Kidney:
Renal arteries are paired branches
arise from aorta at the level of
intervertebral disc between L1,2
Right one longer than the left, passes
behind IVC
At the hilum, each one divides into 5
segmental arteries each supplies a
renal segment
Renal segments are independent in
their blood supply
Blood is drained by segmental veins
to renal veins
Blood Supply of the Urinary System Cont.,
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Abdominal part of ureter:
Uretric branches from the renal
artery are constant ones.
Other branches from gonadal, aorta
and common iliac arteries
They give ascending and descending
branches that anastomose with
each other
Veins are drained by renal and
gonadal veins
Blood Supply of the Urinary System Cont.,
Pelvic part of ureter
• Uretric branches of common iliac, internal iliac and gonadal
arteries
• Constant branches come from inferior vesical and (in female)
uterine arteries
• Veins are corresponded
to arteries
Blood Supply of the Urinary System Cont.,
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Urinary bladder
Superior vesical artery
Inferior vesical artery
Vaginal artery replace inferior vesiacal
artery in female
In male, venous plexus around the bladder
and prostate drain into inferior vesical vein
Also, superior vesical vein drains the
bladder
Both veins drain into internal iliac vein
In female, venous plexus around bladder
drain into vaginal or uterovaginal vein and
then to internal iliac vein
Also, superior vesical vein drains the
bladder
Lymphatic drainage
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Kidney
Into left and right lumbar
(aortic and caval) lymph nodes
Upper ureter
To kidney lymphatics or
to lumbar lymph nodes
Middle ureter
To common iliac lymph nodes
Lower ureter
To common , external,
and internal iliac lymph nodes
Pelvic ureter and bladder
To internal iliac lymph nodes
Nerve Supply
• Parasympathetic fibers leads to
contraction of smooth fibers in
ureter and bladder and relaxation
of smooth fibers in internal urethric
sphincter
• Sympathetic fibers cause the
opposite effect
• Sympathetic fibers to kidney are
vasomotor comes from renal plexus
• Parasympathetic fibers from S2-4
form pelvic splanchnic nerve
• Sympathetic fibers from L1-2 form
inferior hypogastric plexus
Male Urethra
• It is 20 cm long in male from the bladder
neck to external urethral meatus
• It has a tortous course
• It divides into three parts:
1. Prostatic part:
widest portion
It is 3 cm long
Most dilatable part
Ducts of prostate gland and
ejaculatory ducts open in it
2. Membranous part:
Lies within urogenital diaphragm
It is 1.5 cm long
Least dilatable part
Male Urethra cont.,
3. Penile part:
It is 15.5 cm
Is surrounded by erectile
tissue of bulb and corpus
spongiosum
It is dilated at the end as
navicular fossa
Bulbourethral and penile
glands open in it
Female Urethra
• It is 4 cm in length and 6 mm in diameter
• Extends from neck of bladder to external
meatus
• It passes under the symphysis pubis
• It lies anterior to vagina
• It opens in the vestibule anterior to
vaginal opening
• Paraurethral glands
They are mucus secreting glands located
at the sides of external meatus
• It is easily dilatable
• It is straight
Blood Supply of Urethra
Male Urethra
• Prostatic branches of
inferior vesical and middle
rectal arteries
• Dorsal artery of the penis
• Arteries of the bulb of the
penis
Female Urethra
• Internal pudendal artery
• Vaginal artery
Nerve Supply of Urethra
• Parasympathetic supply
From pelvic plexus made of S2-4 roots to form pelvic
splanchnic nerve
• Sympathetic supply T12-L1-2
Form hypogastric plexus and then form pelvic
• Somatic supply
Pudendal nerve from sacral plexus
Sensory and motor to external urethral sphincter
Surface Anatomy
Kidney
Ureter
• Anteriorly is represented by
• Hilum of each kidney is three
a line from a point 5 cm
finger breadth from the midline
from the midline at level of
in transpyloric line (L1)
L2 to a point at anterior iliac
• On the back, kidney extends
spine and from there a
from spine of T12 to spine of L3
curved line is drawn anterior
• Kidney move about one inch on
and medially to pubic
respiration
tubercle
• Right kidney is one inch lower
• Posteriorly is represented by
than the left because of liver
a line from spine of L1 to
posterior inferior iliac spine