Download URINARY SYSTEM

URINARY SYSTEM
KIDNEYS AND URETERS
• 1- Describe the normal site, size, shape and position of
the kidney
• 2- Delineate the surface anatomy of the kidney
• 3- Describe the facsia surrounding the kidney
• 4- Describe the blood supply of the kidney
• 5- Describe the beginning termination, and parts of the
ureter
• 6- Discuss the normal sites of ureteric constrictions
OBJECTIVES
Organs of the Urinary
System
• Organs of the
Urinary system
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Kidneys
Ureters
Urinary bladder
Urethra
Copyright © 2008 Pearson
Education, Inc., publishing as
Benjamin Cummings
Figure 23.1a
Kidneys
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Bean shaped organs
Located retroperitoneally
Lateral to T12–L3 vertebrae
R kidney lower than L (due to R lobe of liver)
kidney levels change during respiration and postural
changes
• Average kidney
• 12 cm tall, 6 cm wide, 3 cm thick
• tilted: superior poles are closer to midline than inferior
• Hilum
• On concave surface
• Vessels, lymphatics and nerves enter and exit
• Renal capsule surrounds the kidney
Location and External Anatomy of Kidneys
Relationship of the Kidneys to Vertebra and
Ribs
Copyright © 2008 Pearson
Education, Inc., publishing as
Benjamin Figure
Cummings
23.1b
1. renal fascia (outer)
• Extraperitoneal fascia, attaches kidney to posterior
abdominal wall – flexible, allows kidney to move
with respiration
• covered by a layer of fat (Pararenal or paranephric)
• The suprarenal glands are included inside this layer
2. perirenal fat (middle layer)
• protective cushion
• Completely surrounds the kidney
3. renal capsule (innermost)
• layer of collagen fibers - barrier against trauma,
infection etc.
• kidney hangs suspended by collagen fibers and
packed in soft cushion of adipose tissue
Renal fascia and fat
outer cortex: pale,
inner medulla
• 6-18 conical renal
pyramids
• apex - renal papilla
projects into the renal
sinus
renal columns
• extensions from cortex
inward to renal sinus
between adjacent renal
pyramids
Internal anatomy
• ureter enters renal sinus, it expands
to form a chamber called - renal
pelvis
• pelvis branches to form 2-3 major
calyces
• branch further to form 6-8 minor
calyces
• Each minor calyx surrounds the
papilla of a renal pyramid
• ducts within papilla connect to wall
of the calyx and discharge urine
produced in the cortex and medulla
• Urine passes through the calyces
into the ureter
Internal anatomy
• Blood Supply
• Single renal artery arises
just inferior to the origin of
the superior mesenteric
artery between vertebrae
LI and LII
• The left renal artery
usually arises a little higher
than the right, and the
right renal artery is
longer and passes posterior
to the inferior vena cava.
• Extra hilar arteries???
• Multiple renal veins contribute to the formation of the left
and right renal veins, both of which are anterior to the
renal arteries
• Importantly, the longer left renal vein crosses the
midline anterior to the abdominal aorta and posterior to
the superior mesenteric artery and can be compressed by
an aneurysm in either of these two vessels.
Renal arteries from abdominal aorta enter hilum and branch:
1. Interlobar arteries - pass through renal columns and reach
junction between medulla and cortex
2. Arcuate arteries run parallel with the base of the pyramids
3. Interlobular arteries move up into the cortex and branch to
form the afferent arteriole
The peritubular capillaries unite to form the interlobular veins,
arcuate vein, interlobar vein, renal vein
The renal vein exits at hilus and joins the IVC
Blood supply of the kidney:
= Functional unit of the kidney, ~ 1 million nephrons per
kidney!
Tubular components:
1. Glomerular (Bowman’s) capsule –
2. Proximal convoluted tubule –
3. Loop of Henle - hair-pin loop
• thin descending limb, thick ascending limb
4. Distal convoluted tubule - last section
• specialized region - Juxta glomerular apparatus
Distal convoluted tubule opens into the collecting system
collecting ducts
papillary ducts
calyx…
Nephron
minor
Made up of blood vessels:
1. Glomerulus - network of capillaries within Bowman’s
capsule
2. Afferent arteriole - leading into glomerulus
3. Efferent arteriole - leading out of glomerulus
4. Peritubular capillaries - surrounding tubules
5. Vasa recta - specialised loops of blood vessels around
long Loop of Henle (juxtamedullary nephrons)
Vascular components of nephron
Nephrons: 85% are cortical, 15% are juxtamedullary
Martini p957
Ureters
Ureters
Pyelogram (colour-enhanced)
• tubes that transport urine
from renal pelvis to bladder
• 20-30 cm long
• Run from the renal pelves,
pass over the pelvic brim at
the bifurcation of the
common iliac arteries.
• Then along the lateral wall
of the pelvis, to enter the UB
• Sites of constriction of the
ureters:
1- At the junction of the ureter and the renal
pelvis ( Ureteropelvic junction)
2- Where the ureters cross the common iliac
arteries at the pelvic brim
3- during their entery through the wall of the
urinary bladder.
Stones become lodged in these sites
•THANK YOU