1. The Urinary System

2. Introduction Function of Urinary System
Cellular metabolism produces wastes
Urea
Uric Acid
Ammonia
Creatinine
Kidneys rid the body of most nitrogenous wastes
Kidneys regulate the chemical make-up of blood
Regulate blood volume as well as RBC production
Blood Pressure
Regulate electrolytes

3. General Functions
Serves as a blood filter
Toxins, metabolic wastes leave the body in urine
H2O, glucose, and amino acids are returned to blood

4. Organs of the Urinary System
Kidneys (paired)
Perform filtering functions and manufacture urine
Ureters (paired)
Transport urine
Urinary bladder (single)
Stores urine
Urethra (single)
Transports urine

5. The Urinary System FG26_01A1.JPG
Title: An Introduction to the Urinary System
Notes: (a) Anterior view, posterior view; urinary system components. (b)Sectional view.
Keywords: urinary system, kidney, ureter, urinary bladder, urethra, inferior vena cava, adrenal gland, renal artery, vein, aorta, parietal peritoneum, adipose capsule, renal capsule

6. Location of Kidneys
Lie against the dorsal body wall
Covered in adipose tissue
In the superior lumbar region
Protected by the lower part of the rib cage

7. The Urinary System FG26_01A2.JPG
Title: An Introduction to the Urinary System
Notes: (a) Anterior view, posterior view; urinary system components. (b)Sectional view.
Keywords: urinary system, kidney, ureter, urinary bladder, urethra, inferior vena cava, adrenal gland, renal artery, vein, aorta, parietal peritoneum, adipose capsule, renal capsule

8. External Structure of the Kidney
Renal capsule
Connective tissue
Renal artery
Blood (oxygenated) to the kidney
Renal vein
Receives blood from kidney
Ureter
Drains urine

9. Internal Structure of the Kidney
Renal cortex
Renal medulla
Renal pyramids
Renal pelvis
Continuous with ureter
Calyces
Extensions of the pelvis
Function – collect urine

10. Structure of the Kidney
FG26_03A1.JPG
Title: Structure of the Kidney
Notes: (a)Frontal section through kidney. (b)Shadow drawing showing arrangement of calyces and renal pelvis. (c)Urogram showing calyces, renal pelvis, and ureter.
Keywords: kidney, frontal, cortex, medulla, renal sinus, renal capsule, hilus, ureter, renal papilla, renal capsule, renal columns, minor calyx, major calyx, renal pelvis, renal pyramids

11. Blood Supply of the Kidney
Approximately ¼ of the total blood supply of the body passes through the kidneys each minute
Renal artery branches inside the kidney
Supplies the pyramids and the cortex
Venous blood leaves the cortex and medulla
Small veins join the renal vein

12. Blood Supply of the Kidney
FG26_07A.JPG
Title: Blood Supply to the Kidneys
Notes: The flow chart summarizes the pattern of renal circulation. (a) Sectional view. (b)Circulation in the cortex. (c)Circulation to a cortical nephron. (d)Blood vessels at a juxtamedullary nephron.
Keywords: kidneys, blood supply, circulation, artery, vein, renal, semental, interlobar, arcuate, interlobular, afferent, efferent, peritubular capillaries, arterioles, venules, cortex, pyramid, interlobular, peritubular capillaries, glomerulus, suprarenal artery

13. Nephrons and Urine Formation
Nephrons form the urine product
Filtration
Reabsorption
Secretion
Each kidney contains about 1 million nephrons

14. Structure of a Nephron 2 main structures
Glomerulus – a knot of capillaries
Renal tubule (about 2 inches long)
Bowman’s capsule surrounds the glomerulus
Proximal convoluted tubule
Henle’s Loop
Distal convoluted tubule
Renal tubule enters collecting duct
Receives urine from nephrons
Delivers final urine product into the calyces

15. A Typical Nephron FG26_04.JPG Title: A Typical Nephron
Notes: Diagrammatic view indicating major functions of each segment of the nephron and collecting system.
Keywords: nephron, renal corpuscle, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting system, papillary duct

16. A Typical Nephron FG26_05A.JPG Title: The Renal Corpuscle
Notes: (a) A juxtamedullary nephron. (b)SEM of several renal corpuscles. (c)Renal corpuscle. (d)Diagrammatic view of filtration apparatus. (e)Electron micrograph of glomerular surface.
Keywords: nephron, juxtamedullary, renal corpuscle, loop of Henle, convoluted tubule, proximal, distal, juxtaglomerular apparatus, macula densa, arteriole, glomerulus, podocyte, capsular space, filtration apparatus, mesangial cell, lamina densa

17. Renal Corpuscles FG26_05B.JPG Title: The Renal Corpuscle
Notes: (a) A juxtamedullary nephron. (b)SEM of several renal corpuscles. (c)Renal corpuscle. (d)Diagrammatic view of filtration apparatus. (e)Electron micrograph of glomerular surface.
Keywords: nephron, juxtamedullary, renal corpuscle, loop of Henle, convoluted tubule, proximal, distal, juxtaglomerular apparatus, macula densa, arteriole, glomerulus, podocyte, capsular space, filtration apparatus, mesangial cell, lamina densa

18. Blood Supply of the Nephron
FG26_07C.JPG
Title: Blood Supply to the Kidneys
Notes: The flow chart summarizes the pattern of renal circulation. (a) Sectional view. (b)Circulation in the cortex. (c)Circulation to a cortical nephron. (d)Blood vessels at a juxtamedullary nephron.
Keywords: kidneys, blood supply, circulation, artery, vein, renal, semental, interlobar, arcuate, interlobular, afferent, efferent, peritubular capillaries, arterioles, venules, cortex, pyramid, interlobular, peritubular capillaries, glomerulus, suprarenal artery

19. Urine Formation Filtration Blood in vessels is under high pressure
Glomerulus acts as a filter
Filtrate = the substance that is filtered from the blood into the renal tubule
Reabsorption
Filtrate contains useful substances which are returned to the blood
Most occurs in the proximal convoluted tubules
Secretion
Substances move from blood (capillaries) into the filtrate
Important in controlling pH of blood
Acid-base balance of blood
Blood pH must be 7.35 – 7.45 (very narrow range)
Tubule cells secrete whatever is necessary into filtrate
Urine pH = 4.5 – 8.0

20. Summary of Urine Flow
Kidneys produce urine
Filtration
Reabsorption (active transport)
Secretion
Ureters
Bladder
Urethra