Download The Urinary System

The Urinary System
Consists of 2 kidneys, Ureter ,Urinary bladder & Urethra
The kidney is a bean shaped organ being located retroperitoneally on each side of the the
vertebral column from T11- L3.The right one is at lower level than the left one due to liver.
Each kidney has 2 poles, 2 margins & 2 surfaces.The medial concave margin has a vertical slit
leading to a cavity known as Renal sinus.The slit is the Hilum.At hilum renal A enters,renal V
leaves & the expanded upper part of ureter ( renal pelvis ) reaches the kidney.The hilum is at
Transpyloric plane.Each kidney is 11 , 6 & 3 cm,while its weight is 120-150 gms.
Each kidney has the following coverings:
1-Fibrous capsule
2-Perirenal fat
3-Renal fascia
4-Pararenal fat
The kidney has outer cortex & inner medulla.The cortex shows renal columns ,while the
medulla contains many pyramids whose apex ( papilla) leads medially to open into the
minor calyces.A pyramid capped by the cortex is renal lobe.The renal pelvis enters & divides
into 2-3 major calyces & 7-14 minor calyces.
The kidney is supplied by renal artery coming from Abdominal Aorta & is drained by renal
vein into the inferior vena cava.At the hilum the renal A id divides into anterior & posterior
branches ,which in turn gives segmental branches( Renal vascular segmentation of about 5
segments).The lymphatic drains into the Para aortic nodes.
The Ureter
Is a narrow muscular tube of 25 cm in length & 3 mm in diameter.The upper half runs in the
abdomen ,while lower half in the pelvis after crossing the pelvic brim&is retroperitoneal.
Near the bladder it is crossed by the ductus deferens from lateral to medial in the
male,while in the female runs just behind the Ovary& medially is very close to Uterine A.
Along its length has 3 constriction sites ,first as it starts, then as it crosses pelvic brim
&finally as it enters the urinary bladder ( intramural course).
The Relations of the kidneys are as follows:
A-The posterior relations of the kidneys are the same and includes
Four muscles on posterior abdominal wall includes Diaphragm, quadratus
lumborum,transversus abdominis & psoas major muscles ( most posterior parts of both)
Between the kidney & these muscles embedded the subcostal A& nerve in addition to
iliohypogastric & ilioinguinal of first lumber nerve .
B- The anterior relations of each kidney are as follows :
1-The right kidney we have the R,Suprarenal gland on superomedial aspect, Descending
part of Duodenum on the hilum , the Right colic flexure on the inferolateral side ,the coils of
small intestine in the inferomedial part & the right lobe of the liver superolaterally
2-The left kidney we have the left suprarenal gland , the tail of pancreas cossing in front
of the hilum & part of anterior surface,the just above this area the left kidney is related to
the stomach(fundic region ) ,inferolaterally to splenic flexure & inferomedially to the coils of
small intestine & superolaterally to the spleen.