1. The Urinary System

2. Functions of the Urinary System
Removal of metabolic wastes (especially nitrogenous wastes e.g. urea & uric acid).
Water balance (and therefore blood pressure).
Control of electrolyte balance.
Control of pH.
Removal of toxins.

3. Anatomy of the Urinary System
The Kidneys: the functional heart of the urinary system.
The Ureters: pipeline from the kidneys to the bladder.
The Urinary Bladder: holding tank of urine.
The Urethra: avenue of relief
(word of the day “micturition” = voiding the bladder)

4. Urinary System Components

5. The Kidneys
Location: retroperitoneal against the dorsal wall of the abdominal cavity. The right kidney is slightly lower than the left.
Size & weight: approximately 150 grams (about 5 ounces) each and 12 cm x 10 cm x 4 cm.
Shaped like a bean (or are beans shaped like kidneys?)

6. The Position of the Kidneys
Figure 26–2

7. Gross Anatomy of the Urinary System
Figure 26–3

8. The Structure of the Kidney
Figure 26–4

9. Blood Supply to Kidneys
Kidneys receive 20–25% of total cardiac output
ml of blood flows through kidneys each minute
Kidney receives blood through renal artery

10. Blood Supply to the Kidneys
Figure 26–5

11. A slice of kidney
Cortex
Medulla
Glomeruli
Capsule

12. The Nephron: functional unit of the kidney
Interlobular artery
Afferent Arteriole
Glomeruli

13. Functional Anatomy of Nephron and Collecting System
Figure 26–6

14. Renal Corpuscle

15. Filtrate & Urine flow

16. Cortical and Juxtamedullary Nephrons
Figure 26–7

17. The renal corpuscle and the Juxtaglomerular apparatus

18. The renal filtration membrane: Podocytes and fenestrated capillaries

19. Filtration slits
Pedicles

20. The filtration membrane

21. An Overview of Urine Formation
Figure 26–9 (Navigator)

22. Filtration pressures: NFP must be positive for U2P

23. Formation of dilute urine

24. After the Kidneys: the bladder & urethra

25. Male
Figure 26–18a

26. Female v
Figure 26–18c

27. It can hold a maximum of 800 – 1000 ml!

28. Histology

29. Composition of Urine Abnormal Normal Glucose “glycosuria” Urea
Proteins “proteinuria” or
“albuminuria”
Ketones “ketonuria”
Hemoglobin “hemoglobinuria”
Erythrocytes “hematuria”
Bile pigments “bilirubinura”
Leukocytes “pyruia”
Normal
Urea
Uric acid
Creatinine Na K
Phosphates
Sulfates
Bicarbonate Ca Mg
Abnormally low output = oliguria
No output = anuria
Abnormally high output = polyuria
Diuresis = increased urine output
Diuretic = substance that leads to diuresis

30. Kidney stones

31. “Well Mr. Osborne, I don’t think that it’s kidney stone after all”