The Urinary System

1. The Urinary System

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

3. Kidneys as Filters • Diuretic- loose water; coffee, alcohol • Antidiuretic- 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. The Urinary System Maintaining Chemical Homeostasis

6. The Urinary System

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

8. Nitrogenous Wastes urea uric acid ammonia

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

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

11. nephron renal artery renal vein Kidney Anatomy

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

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

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

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

16. Composition of Glomerular Filtrate • Water • Small Soluble Organic Molecules • Mineral Ions

17. Proximal Convoluted Tubule Reabsorbs: water, glucose, amino acids, and sodium. • 65% of Na+ is reabsorbed • 65% of H2O is reabsorbed • 90% of filtered bicarbonate (HCO3-) • 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. Urine • Water- 95% • Nitrogenous waste: • urea • uric acid • creatinine • Ions: • sodium • potassium • sulfate • phosphate From the original 1800 g NaCl, only 10 g appears in the urine

22. Hormonal Control of Kidney Function

23. heart receptors hypothalamus Hormonal Control of Kidney Function high plasma solute concentration low blood volume

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

25. Hormonal Control of Kidney Function

26. juxtaglomerular apparatus renin Hormonal Control of Kidney Function reduced blood pressure and glomerular filtrate

27. angiotensinogen angiotensin I angiotensin II Hormonal Control of Kidney Function renin

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

29. ureters internal sphincters external sphincters urethra Urinary Bladder

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

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

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

33. Distension of the Urinary Bladder

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

35. Odor odor- normal is ammonia-like diabetes mellitus- smells fruity or acetone like due to elevated ketone levels diabetes insupidus- yucky asparagus---

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

37. Color 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- bright yellow Infection- cloudy

38. Specific Gravity 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

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

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

41. Abnormal Constitutes of Urine Ketone bodies- normal in urine but in small amts Ketonuria- find during starvation, using fat stores Ketonuria is couples w/a finding of 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

42. Abnormal Constitutes of Urine 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

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

44. Moment of Zen KIDNEY