Transcript 02Ureter,_Urinary_Bladder_&_Urethra

URETERS
URINARY BLADDER
URETHRA
OBJECTIVES
At the end of the lecture, students should be able
to:

Describe the course of ureter & identify the sites of
ureteric constriction
 Describe the important relations & identify certain
areas (trigone, uvula vesicae) in the base of
urinary bladder.
 List the blood supply, lymphatic drainage & nerve
supply of urinary bladder
 Differentiate between male & female urethra
regarding length, structure, course & function.
Ureter



A 25 – 30 cm long
muscular tube transporting
urine from kidney to urinary
bladder.
Begins as a continuation of
renal pelvis.
COURSE IN ABDOMEN:
 It descends anterior to psoas major muscle (opposite the
tips of lumbar transverse processes).
 It crosses the end (bifurcation) of common iliac artery to
enter the pelvis.

COURSE IN PELVIS &
TERMINATION:
 Runs downward in front to internal
iliac artery, reaches ischial spine
 Turns forward and medially ,
enters the upper lateral angle of
urinary bladder
 Near its termination, is crossed by
the vas deferens
 Passes obliquely through the wall
of bladder for about ¾ inch before
opening into the bladder cavity.
Bladder muscle contraction
mechanically closes off ureteral
orifice which prevents a reverse flow
of urine toward the kidney
Ureteric Constrictions

1.
2.
3.
The ureter has
constrictions at
three points (sites of
obstruction and
stone impaction)
At the ureteropelvic
junction
At the crossing of
external/common
iliac artery
At site of entrance
to bladder
1
2
3
Arterial Supply


Ureter is supplied by
multiple arteries
throughout its course
From above downward,
these are::
1.
Renal artery
2.
Gonadal artery
3.
Common iliac artery
4.
Internal iliac artery
1
2
3
4
Urinary Bladder



Located immediately behind
the pubic symphysis
Shape and relations vary
according to the amount of
urine it contains
An empty bladder:
 In adults, is entirely a
pelvic organ; as it fills,
rises up into the
hypogastric region.
 In young children, it
projects above the pelvic
inlet

An empty bladder is
pyramidal in shape
having:
 An apex
 A base (posterior
surface)
 A superior surface
 Two infrolateral
surfaces
 A neck
Apex



Directed forward
Lies behind the upper
margin of the
symphysis pubis
Is connected to
umbilicus by the
median umbilical
ligament (remnant of
urachus)
Base or Posterior
surface

Triangular in shape
 Upper part covered by
peritoneum
 Lower part related to:
 In males: vas
deferentia and
seminal vesicles
 In females: vagina
Superior surface


Completely covered by peritoneum.
Related to the coils of ileum or sigmoid colon in
males and to uterus in females
Male pelvis
Female pelvis
Infrolateral surfaces:


Related in front to the
retropubic pad of fat &
the pubic bones
Posteriorly lie in contact
with the obturator
internus above and
levator ani below
Retropubic fat
 Accomodates distention of bladder
 Continuous with anterior abdominal wall.
 Rupture of bladder results in escape of urine to
anterior abdominal wall
Neck:

Lies inferiorly, and is the
most fixed part of the
bladder
 Is related to lower border
of symphysis pubis
 In male, rests on the
upper surface of
prostate. Here, the
smooth muscle fibers of
the bladder are
continuous with those of
the prostate
 The circular muscle
fibers thickened to form
the sphincter vesicae
Interior of the Urinary Bladder


Mucous membrane thrown
into folds except in the
triangular region in the
base of bladder, between
the openings of the two
ureters and the urethra.
This region is called the
‘trigone’. Here The
mucous membrane is
always smooth even when
the bladder is empty
Uvula vesicae, a small
elevation located just
behind the urethral orifice,
It is produced by the
median lobe of prostate.
Blood & Nerve Supply



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Arterial supply: from internal iliac artery
Venous drainage: into internal iliac vein
Lymphatics: into internal iliac lymph nodes
The nerves form the vesical nerve
plexus that contains:
 Sympathetic fibers derived mainly
from L1,2
 Parasympathetic fibers derived from
pelvic splanchnic nerves S2,3,4
 Sensory fibers from the bladder are
visceral and transmit pain sensation
resulting from overdistention

The normal capacity
of bladder is about
300-500ml.
 As bladder fills, the
superior surface
bulges upward into
abdominal cavity.
 The peritoneal lining
is peeled off the
lower part of
anterior abdominal
wall and the bladder
comes into direct
contact with the
anterior abdominal
wall
Male Urethra

About 8 inches (20cm)
long
 Extends from the neck
of bladder to the
external urinary meatus
on the tip of the glans
penis
 Divided into three
parts:
 Prostatic
 Membranous
 Penile
Prostatic urethra




Length=3 cm
Widest & most dilatable
Extends from neck of
bladder inside prostate
gland
Structures openings into
prostatic urethra:

Ejaculatory ducts

Ducts of prostate gland
Membranous urethra


Length=1 cm
Surrounded by external
urethral sphincter

Penile (spongy) urethra

Length=16 cm
narrowest part of whole urethra
Extends inside penis & opens
externally through external
urethral orifice


Female Urethra


Extends from neck
of urinary bladder
to open externally
through the
external urethral
orifice (anterior to
the vaginal
opening)
Has only urinary
function
FLY
HIGH