1. URINARY SYSTEM KIDNEYS AND URETERS

2. OBJECTIVES 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

3. Organs of the Urinary System

4. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Organs of the Organs of the Urinary system Kidneys Ureters Urinary bladder Urethra Figure 23.1a

5. Kidneys

6. Location and External Anatomy of Kidneys Bean shaped organs Located retroperitoneally Lateral to T 12 –L 3 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

9. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Relationship of the Kidneys to Vertebra and Ribs Figure 23.1b

17. Renal fascia and fat. renal fascia (outer) 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 perirenal fat (middle layer) 2. perirenal fat (middle layer) protective cushion Completely surrounds the kidney renal capsule (innermost) 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

19. Internal anatomy 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

20. 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

22. 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???

23. Multiple renal veins contribute to the formation of the left and right renal veins, both of which are anterior to the renal arteries Importantly, 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.

24. Blood supply of the kidney: 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

27. Nephron = 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 ductspapillary ducts minor calyx…

30. Vascular components of nephron Made up of blood vessels: 1. Glomerulus - network of capillaries within Bowman’s capsule 2. Afferent arteriole - leading into glomerulus Efferent arteriole 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)

31. Nephrons: 85% are cortical, 15% are juxtamedullary Martini p957

32. Ureters

33. 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

36. 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

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