4.02 Understand the Functions and Disorders of the Urinary System

1. 4.02 Understand the Functions and Disorders of the Urinary System

2. 4.02 Understand the functions and disorders of the urinary system Essential Questions • What are the functions of the urinary system? • What are some disorders of the urinary system? • How are disorders of the urinary system treated? • How do you relate the body’s hormone control to the urinary system? 4.02 Understand the functions and disorders of the urinary system

3. Understand the functions of the urinary system Functions: • Excretion • Formation of urine • Fluid and electrolyte balance • Elimination of urine 4.02 Understand the functions and disorders of the urinary system

4. Understand the functions of the urinary system Excretion – process of removing waste and water excess from blood • Composition of wastes – mostly nitrogenous waste and some salts • If these aren’t removed from blood, they would build up and become toxic 4.02 Understand the functions and disorders of the urinary system

5. Understand the functions of the urinary system Formation of urine happens by three processes: Filtration of blood by glomerulus Reabsorption back into blood within the renal tubules Secretion of substances from blood into the urine in the tubules 4.02 Understand the functions and disorders of the urinary system

6. 1. Filtration • Blood from renal artery enters glomerulus • High pressure in glomerulus filters blood by forcing fluid and small particles into Bowman’s capsule • Proteins and blood cells are too large to pass through semi-permeable membrane, so they stay in the blood 4.02 Understand the functions and disorders of the urinary system

7. 1. Filtration • Bowman’s capsule filters out 125 ml of fluid/min. • That’s 7,500 ml/hour • Or 180 L/day 4.02 Understand the functions and disorders of the urinary system

8. 2. Reabsorption • As the urinary filtrate continues through nephron, 99% of water is reabsorbed back into blood • About 80% in proximal convoluted tubule • About 15% in distal convoluted tubule • Responsible for correcting water imbalance of dehydration • Failure to reabsorb = polyuria • Some of other useful substances are also reabsorbed back into blood (some sugar, vitamins, salts…) • If blood levels of certain substances are high, the substances will not be reabsorbed. • How does this help maintain homeostasis? 4.02 Understand the functions and disorders of the urinary system

9. 2. Reabsorption • Because of reabsorption, instead of 180 liters a day, we only produce about 1 – 1.5 liters of urine a day 4.02 Understand the functions and disorders of the urinary system

10. 3. Secretion • Secretion – transports excessive substances in the blood into the distal and collecting tubules • Under chemical and nervous control • opposite direction of reabsorption

11. Understand the functions of the urinary system Fluid and electrolyte balance • Electrolytes are selectively secreted (last step of urine formation) to maintain body’s acid-base balance. • Electrolytes = salts/minerals with electrical charge that help control fluid and acid-base balance 4.02 Understand the functions and disorders of the urinary system

12. Understand the functions of the urinary system Fluid and electrolyte balance - fluid (reabsorption) and electrolyte (secretion) balance are controlled two way • Chemical control • ADH – antidiuretic hormone • Aldosterone • Nervous control 4.02 Understand the functions and disorders of the urinary system

13. Understand the functions of the urinary system FLUID and electrolyte balance - Chemical control -ADH (antidiuretic hormone) – hormone that causes increased reabsorption of water from tubules into blood • Remember: Diuretic = causing an increase passing of urine • So… ANTIdiuretic hormone makes you reabsorb more water. • ADH (antidiuretic hormone) is released by the posterior pituitary gland in response to increased salt concentration in blood 4.02 Understand the functions and disorders of the urinary system

14. Understand the functions of the urinary system Fluid and electrolyte balance - Chemical control -Aldosterone – hormone that causes reabsorption of sodium and water and the secretion of potassium and hydrogen • Specialized cells in nephron detect drop in BP and cause the kidneys to release renin (hormone)  • starts process that ends with adrenal glands (sit on top of your kidneys) secreting aldosterone • Aldosterone increases BP by reabsorbing more water

15. Understand the functions of the urinary system Fluid and electrolyte balance Nervous control • Nerves control blood vessels leading to and inside of the kidneys 4.02 Understand the functions and disorders of the urinary system

16. Understand the functions of the urinary system review • What do you predict will happen to blood pressure when the blood volume increases? • What if blood volume decreases? • What will happen with increased ADH and aldosterone? • What will happen with decreased ADH and aldosterone? 4.02 Understand the functions and disorders of the urinary system

17. Understand the functions of the urinary system • Diuretics = increase output of urine • Some decrease amount of water reabsorbed back into blood • Some increase amount of sodium secreted (water follows salt) • Cause urine to be more diluted • Examples of diuretics: • BLOOD PRESSURE MEDICINES • Caffeine • Alcohol 4.02 Understand the functions and disorders of the urinary system

18. Understand the functions of the urinary system review Dehydration – • When you’re dehydrated, your body reabsorbs more water back into blood • So less water is leaving as urine  • Urine is more concentrated 4.02 Understand the functions and disorders of the urinary system

19. Understand the functions of the urinary system Elimination of urine • Emptying bladder, or voiding, is done by involuntary contraction of the bladder muscle • Two sphincters in urethra have to be open. First is involuntary. Second is voluntary. • Incontinence = involuntary urinating • Babies before they have external sphincter control, spinal cord injury that has lost nerve control to external sphincter • Urinary retention = inability to completely empty bladder. • ex: nerve damage to nerve controls bladder

20. Understand the functions of the urinary system Elimination of urine • Urinary output • Average urinary output = 1500 ml per day • What effects the color of your urine? 4.02 Understand the functions and disorders of the urinary system

21. Urinalysis An examination of urine • What does normal urine look like? • What is an abnormal finding? • What’s the term for blood in the urine and what could that mean? • What about glucose? 4.02 Understand the functions and disorders of the urinary system

22. Disorders of the Urinary system 4.02 Understand the functions and disorders of the urinary system

23. Disorders of the urinary system Cystitis -cyst= sac • Cystitis – inflammation of the lining of the bladder • Most common cause: E. Coli • Enters through the urethra • Most common in women. Why? • Symptoms: • Dysuria • Frequent urination • Hematuria • Cloudy, smelly urine • Treatment: • Antibiotics and increased fluids • Prevention: • Toileting hygiene (front to back) 4.02 Understand the functions and disorders of the urinary system

24. Disorders of the urinary system Glomerulonephritis - • Inflammation of the glomerulus in the nephron • FILTRATION is affected  proteins (like albumin) and red blood cells let through  so found in urine • Symptoms: hematuria, foamy urine (r/t proteins), swelling, high BP • Can be: • ACUTE: usually after strep infection. Treated with antibiotics. Usually recover. May lead to  • CHRONIC: often idiopathic or autoimmune disease related. Treatment to control symptoms. Can lead to kidney failure.

25. Disorders of the urinary system Renal calculi / nephrolithiasis “Kidney Stones” – stones formed in the kidneys • Form when more crystal-forming substances than the fluid in your urine can dilute • Usually no one cause, but related to: calcium, bacteria, high protein diet • Crystals stick together and form stones, can get big enough to fill renal pelvis and block ureter

26. Disorders of the urinary system Renal calculi • Symptoms: (not until big enough) • Extreme flank/back pain • Hematuria • N/V, fever • Hydronephrosis (swelling of kidney r/t blocked outflow of urine) • Diagnosed: symptoms, ultrasound, x-ray with dye) 4.02 Understand the functions and disorders of the urinary system

27. Disorders of the urinary system Renal calculi • Treatment: • Increase fluids • Pain meds • Meds that relax ureters to help the stone pass • Lithotripsy – uses shock waves to break up stones • Ureteroscope – lighted tube with camera to break up stone • Surgery 4.02 Understand the functions and disorders of the urinary system

28. Disorders of the urinary system Renal failure • Acute – kidneys become suddenly unable to filter blood (reversible) • Caused by: • Decreased blood flow to kidneys (bleeding, shock, heart failure) • Damage to kidneys (glomerulonephritis, injury, infection) • Urine blockage in the kidneys (bladder/prostate cancer, kidneys stones) • Symptoms: • Oliguria – anuria: cause swelling, BP issues • Uremia (waste products build up in blood)  HA, N/V, dyspnea, even coma and death • Treatment: • Treat cause and symptoms

29. Disorders of the urinary system Renal failure Chronic – gradual loss of kidney function (over months/years) (often irreversible) • Causes: • Diabetes, high BP, recurrent infections… • Symptoms: • often none in early stages, urinalysis may show proteinuria – why? • Oliguria  anuria: causing swelling, high BP • Uremia causing: • Fatigue • N/V • Itchy skin • Urine smell to breath • Confusion  coma  death • Treatment: (depending on cause- usually no cure) • Treat complications • Dialysis (passes blood through semi-permeable membrane to mimic filtration function of kidneys)

30. Disorders of the urinary system Chronic Renal Failure treatment – types of dialysis • Hemodialysis – a machine passes your blood through a semi-permeable membrane to FILTER out waste products and fluid • Done 2 or 3 times a week. Usually lasts 2-4 hours. • Accessed through AV fistula or AV graft 4.02 Understand the functions and disorders of the urinary system

31. Disorders of the urinary system Chronic Renal Failure treatment – types of dialysis • Peritonealdialysis – uses patient’s peritoneum (semi-permeable membrane in abdomen) to filter out waste and fluid from the blood instead of using a machine. • can be done multiple times a day or overnight (both usually at home) • Dialysis VIDEO (stop at 6 min) 4.02 Understand the functions and disorders of the urinary system

32. Disorders of the urinary system How does hemodialysis mimic glomerular function? 4.02 Understand the functions and disorders of the urinary system

33. Disorders of the urinary system Renal transplant • Transplanting one kidney from a living or deceased donor • If no living matches, go on waiting list for deceased donor • Anti-rejection medicines for rest of life • If kidney fails • Back on dialysis • Attempt second transplant • Stop treatment 4.02 Understand the functions and disorders of the urinary system

34. 4.02 Understand the functions and disorders of the urinary system • Essential Questions • What are the functions of the urinary system? • What are some disorders of the urinary system? • How are disorders of the urinary system treated? • How do you relate the body’s hormone control to the urinary system? 4.02 Understand the functions and disorders of the urinary system