Urinary System (quizlet)

• What is the normal ration of cortex to medulla in the kidney?

  1:2 or 1:3

  
  

  (Can reach 1:5 in dromedary camels)

  
• Desert dwellers have a longer (cortex/medulla)

  medulla
• Why do renal infarcts appear in the shape of a pyramid?


  Due to the nature of the blood supply

  
• Which species has prominent renal vasculature?

  Cats
• Which blood vessel runs along the cortico-medullary junction?

  Arcuate artery and vein
• Which artery do afferent arteries come off of?

  Interlobular arteries

  
• How many nephrons are dogs born with?

  1,000,000
• How many nephrons would have to be non-functional before clinical signs appear?

  75,000 (75%)
• What is an end artery?

  An artery that is the sole source of blood supply to a given tissue
• What is the pathologic implication of end arteries in the kidneys?

  If blood supply is compromised to a portion of the kidney, there is no collateral circulation. This makes renal tissues prone to ischemic injury and infarct if there is a thrombotic event.
• What does end-stage kidney disease look like grossly?

  Kidneys are small, pitted, and fibrotic

  
• How does end-stage kidney disease affect Vit D metabolism, Ca:P ratio, and parathyroid hormone production?

  Kidney disease causes renal retention of phosphorus and loss of calcium, which throws off the Ca:P ratio, which should normally be 2:1. (This is sometimes referred to as "renal rickets")

  
  

  The active form of vitamin D is produced in the kidney so renal dysfunction makes it hard for the animal to produce this Vit D, which is needed for absorption of dietary calcium.

  
  

  Low serum ionized calcium levels signal the release of parathyroid hormone from the PT gland. This causes release of calcium from the "storage depot", the bones.

  
  

  Now the animal is hypercalcemic and the may experience metastatic hypercalcemia.
• Name a musculoskeletal consequence of end stage kidney disease

  - Fibrous osteodystrophy (if too much calcium is taken from the bones)

  - Metastatic mineralization

  - Pleural crusting

  - Renal rickets

  
• Compare acute vs. chronic infarcts in most species

  Acute - Red, raised

  
  

  Chronic - shrunken, indented

  
• What is unique about infarcts in rabbits?

  Acute infarcts in rabbits are PALE and raised
• How can you differentiate between tubular change that is ischemic vs. hypoxic in nature?


  Ischemic - patchy, short lengths of tubular necrosis

  Toxic - extensive necrosis along PCT

  Both types of tubular disease- can see casts in the urine
• Nephrotic syndrome


  Protein loss (albumin,antithrombin III, etc) into the urine due to severe glomerular damage.

  Can result in a hyper- coagulable state.

  Findings include:

  - Hyperproteinuria

  - Hypoproteinemia

  - Hypercholesterolemia

  - Edema
• Which type of glomerulonephritis is most common in cats?

  Membranous

  
• Which type of glomerulonephritis is most common in dogs?

  Membranoproliferative

  
• What is a key clin path finding of glomerular disease (such as glomerulonephritis)?

  Proteinuria
• What is a common sequela of severe glomerular amyloidosis and proteinuria in dogs?

  Thrombosis
• What are possible causes of tubular injury?

  - ISCHEMIA

  - Hemolysis

  - Crystals

  - TOXINS

  - Bacteria (leptospira)
• What is a characteristic finding for nephrosis?

  Casts in urine

  
• What are some gross consequences of urinary obstruction?

  Unilateral ureter obstruction - unilateral hydronephrosis

  
  

  Urethral obstruction - bilateral hydronephrosis
• How does diabetes predispose patients to recurrent lower UTI?

  There are valves in the ureters that prevent backflow of urine. In diabetic patients, these valves don't function properly and this makes it easier to them to get ascending UTIs. Glucose-rich urine also makes a good medium for bacterial growth.
• How does urolithasis relate to UTIs?

  Urase-producing bacterial can change the pH of urine and cause inflammation, predisposing animals to urolithiasis
• __________________ is an inherited, autosomal dominant condition seen in Persian cats, dogs, pigs, and lambs

  Polycystic kidney disease

  
• Mutations in what results in polycystic kidney disease?

  polycystin 1, 2 or fibrocystin

  
• How can an animal get polycystic kidneys (acquired)?

  Chronic inflammation
• You are doing a necroposy on a persian with polycystic kidney disease. What are two other organs of interest to check for cysts?

  Pancreas and liver
• Explain how excess antigen (from chronic infection, ear infection, dental disease, etc) can lead to glomerulonephritis?

  Excess antigen sticks to the glomeruli, recruiting immune cells that cause local inflammation. This inflammation damages podocytes and glomerular tufts, so proteins can leak out of glomeruli. This is why we see proteinuria with glomerular disease.
• What is glomerular amyloidosis?


  When amyloid, an insoluble B-pleated sheet protein deposits in glomeruli, disrupting renal filtration

  
• Renal tubules can recover from toxic insult, but cannot recover from ischemic insult
• Which part of the kidney is most prone to NSAID toxicity?

  Papillary (medullary) crest
• A lame horse has been given phenylbutazone for months. Which three areas are we concerned about?

  - Papillary crest

  - Cartilage

  - GI tract
• Which areas of the kidney do you expect to be most affected by an ascending bacterial infection that causes pyelonephritis?

  Poles of the kidney

  
• Describe the gross appearance you'd expect for hematogenous embolic nephritis


  Diffuse, milliary pattern

  
• Give examples of urinary system developmental anomalies that can result in disease?

  - ureteral aplasia (agenesis)

  - Hypoplasia

  - Ectopic ureters

  - Patent urachus (urine leaking from umbilicus)
• Obstructive urinary disease are most commonly due to what?

  Urolithiasis

  
• Which animals are more prone to bladder rupture in the case of urolithiasis?

  Young animals