1. The Urinary System

2. Function 1.Remove nitrogenous wastes 2.Maintain electrolyte, acid-base, and fluid balance of blood 3.Homeostatic organ 4.Acts as blood filter 5.Release hormones: calcitriol & erythropoietin

3. Kidneys as Filters Diuretic- you lose water; coffee, alcohol Antidiuretic- you retain water; ADH Aldosterone- sodium & water reabsorption, and K + excretion GFR= 180 liters (50 gal) of blood/day 178-179 liters are reabsorbed back into blood Excrete a protein free filtrate

5. Maintaining Chemical Homeostasis The Urinary System

7. urine blood filtration tubular reabsorption and secretion General Functioning of the Kidney “refreshed” blood

8. Nitrogenous Wastes ammonia urea uric acid

9. Organs of the Urinary System kidneys ureters urinary bladder urethra

10. renal capsule renal cortex renal medulla renal pelvis renal pyramids ureter Kidney Anatomy

11. renal artery renal vein nephron

12. urine blood filtration tubular reabsorption and secretion Nephron Functioning “refreshed” blood

13. vein artery afferent arteriole efferent arteriole glomerulus peritubular capillaries Bowman’s capsule proximal convoluted tubule distal convoluted tubule loop of Henle collecting duct

14. renal cortex renal medulla Each kidney contains over 1 million nephrons and thousands of collecting ducts Collecting duct Loop of Henle PCT DCT Glomerulus

15. Glomerular Filtration afferent arteriole glomerulus efferent arteriole Bowman’s capsule Filters blood; proteins can’t pass through

16. Composition of Glomerular Filtrate WaterWater Small Soluble Organic MoleculesSmall Soluble Organic Molecules Mineral IonsMineral Ions

17. Proximal Convoluted Tubule Reabsorbs: water, glucose, amino acids, and sodium. 65% of Na + is reabsorbed 65% of H 2 O is reabsorbed 90% of filtered bicarbonate (HCO 3 - ) 50% of Cl - and K +

18. Loop of Henle Creates a gradient of increasing sodium ion concentration towards the end of the loop within the interstitial fluid of the renal pyramid. 25% Na+ is reabsorbed in the loop 15% water is reabsorbed in the loop 40% K is reabsorbed in the loop

19. Distal Convoluted Tubule Under the influence of the hormone aldosterone, reabsorbs sodium and secretes potassium. Also regulates pH by secreting hydrogen ion when pH of the plasma is low. only 10% of the filtered NaCl and 20% of water remains

20. Collecting Duct Allows for the osmotic reabsorption of water. ADH (antidiuretic hormone)- makes collecting ducts more permeable to water-- produce concentrated urine

21. From the original 1800 g NaCl, only 10 g appears in the urine Urine Water- 95% Nitrogenous waste: urea uric acid creatinine Ions: sodium potassium sulfate phosphate

22. Hormonal Control of Kidney Function

23. low blood volume high plasma solute concentration hypothalamus heart receptors

24. Hormonal Control of Kidney Function hypothalamus posterior pituitary antidiuretic hormone collecting ducts

25. Hormonal Control of Kidney Function

26. reduced blood pressure and glomerular filtrate juxtaglomerular apparatus renin

27. Hormonal Control of Kidney Function reninangiotensinogen angiotensin I angiotensin II

28. Hormonal Control of Kidney Function adrenal cortex aldosterone angiotensin II convoluted tubules

29. Urinary Bladder ureters internal sphincters external sphincters urethra

30. Bladder 1.Mucosa (transitional epithelium) 2.Muscular layer (detrusor muscle): 3 layers of smooth muscle 3.Fibrous adventia

31. Internal urethral sphincter: Smooth muscle Involuntary control More superiorly located External Urethral sphincter: Skeletal muscle Voluntary control Posteriorly located Sphincter Muscles on Bladder

32. When bladder fills with 200 ml of urine, stretch receptors transmit impulses to the CNS and produce a reflex contraction of the bladder (PNS) Diuresis (Micturition) When is incontinence normal?

33. Distension of the Urinary Bladder

34. Why do doctors ask for a urine sample? Urinalysis characteristics: smell- ammonia-like pH- 4.5 to 8, average is 6.0 specific gravity– more than 1.0; usually about 1.001-1.003 color- affected by what we eat: salty foods, vitamins

35. odor- normal is ammonia-like diabetes mellitus- smells fruity or acetone-like due to elevated ketone levels diabetes insupidus- yucky Food can also alter urine odor (asparagus) Odor

36. pH- range 4.5 to 8, average 6.0 vegetarian diet- urine is alkaline protein rich and wheat diet- urine is acidic

37. Color- pigment is urochrome Yellow color due to metabolic breakdown of hemoglobin (by bile or bile pigments) Beets or rhubarb- might give a urine pink or smoky color Vitamins: vitamin C makes urine bright yellow Infection makes urine cloudy Color

38. Water: s.g. = 1g/liter; Urine: s.g. ~ 1.001 to 1.030 Pyelonephritus- urine has high s.g.; form kidney stones Diabetes insipidus- urine has low s.g.; drinks excessive water; injury or tumor in pituitary Specific Gravity

39. Glucose- when present in urine, the condition is called glycosuria (nonpathological) [glucose not normally found in urine] Indicative of: Excessive carbohydrate intake Stress Diabetes mellitus Abnormal Constitutes of Urine

40. Albumin-abnormal in urine; it’s a very large molecule, too large to pass through glomerular membrane > so its presence indicates an abnormal increase in permeability of membrane Albuminuria- nonpathological conditions- excessive exertion, pregnancy, overabundant protein intake-- leads to physiologic albuminuria Pathological condition- results from kidney trauma due to blows, heavy metals, bacterial toxin Abnormal Constitutes of Urine

41. Ketone bodies- normal in urine but only in small amounts Ketonuria- occurs during starvation, fat stores are used. Ketonuria is coupled with glycosuria-- which is usually diagnosed as diabetes mellitus RBC-hematuria Hemoglobin- Hemoglobinuria- due to fragmentation or hemolysis of RBC; conditions: hemolytic anemia, transfusion reaction, burns or renal disease Abnormal Constitutes of Urine

42. Bile pigments- Bilirubinuria (bile pigment in urine)- liver pathology such as hepatitis or cirrhosis WBC- Pyuria- urinary tract infection; indicates inflammation of urinary tract Casts- hardened cell fragments, cylindrical, flushed out of urinary tract WBC casts- pyelonephritus RBC casts- glomerulonephritus Fatty casts- renal damage Abnormal Constitutes of Urine

43. INQUIRY 1.List several functions of the kidneys. 2.What does the glomerulus do? 3.What are several constitutes you should not find in urine? 4.What is specific gravity? 5.What two hormones effect fluid volume and sodium concentration in the urine? 6. Where are the pyramids located in the kidney? 7.What vessel directs blood into the glomerulus? 8.Where does most selective reabsorption occur in the nephron?