Urinary System

Question 1

Water only moves _______ in the kidney

Answer 1

Passively

Question 2

Thick asending limb (loop of henle)

Answer 2

Impermeable to water and actively removes Na and Cl from urine

Question 3

Distal tubule and collecting duct

Answer 3

Selectively permeable to water (vasopressin/ ADH opens pumps so water can be reabsorbed)

Question 4

Urea in the kidney

Answer 4

In the collecting duct, recycled into the medulla passively down a concentration gradient (helps with concentration)
Acquired from diet (through liver)

Question 5

How the kidney concentrates urine:

Answer 5

Glomerulus → proximal renal tubule→ Loop of Henle → collecting tubules

Question 6

Glomerulus

Answer 6

Blood supply, filtration (small molecules) and supplies the kidney with nutrients

Question 7

Normal SG

Answer 7

300 osmol= 1.008-1.012
Less than= dilute

Question 8

Proximal renal tubule

Answer 8

Absorbs water and electrolytes (non-selectively)

Question 9

Loop of Henle

Answer 9

Separates water from electrolytes : Na, Cl- pumps from ascending limb → renal interstitial
Dilutes urine

Question 10

Dilution

Answer 10

Remove solutes in excess of water (urine less concentrated)

Question 11

How does the renal medulla become hyperosmotic?

Answer 11

@ the Loop of Henle (ascending limb)
Na/Cl pumping electrolytes out of limb into the central medulla

Question 12

Counter current multiplier

Answer 12

Forming a concentrated urine
Loop of henle generates an hyperosmotic medulla for separation of water an solutes
Requires energy, hairpin configuration and separation of water from solute

Question 13

How is the hyperosmotic medulla maintained after water enters

Answer 13

Vasa recta: water moves in to dilute hyperosmotic medulla → collects water from medulla and brings it back to the urinary system circulation (prevents solute washout)

Question 14

Vasa recta (counter current exchanger)

Answer 14

Blood supply to the medulla bringing nutrients and O2 and removing waste
OG from JG nephrons

Question 15

Requirements for the counter current exchanger

Answer 15

Hairpin configuration
High permeability to water and solutes
Slow circulation to allow diffusion

Question 16

What 2 things are required to form a concentrated urine?

Answer 16

Hyperosmotic renal medulla and ADH (vasopressin)

Question 17

Water deficit

Answer 17

↑ extracellular osmolality, ADH secretion, plasma ADH, H2O and urea permeability, H2O and urea reabsorption and ↓ H2O excretion
done to conserve water

Question 18

Water excess

Answer 18

↓extracellular osmolality, ADH secretion, plasma ADH, H2O and urea permeability, H2O and urea reabsorption and ↑H2O excretion
excreting water and diluting urine

Question 19

Kidney function (maintaining homeostasis)

Answer 19

Filter our metabolic waste
Maintain hydration and electrolyte balance (P,K, Na)
Prevent plasma protein loss
Acid base and calcium balance
BP control
RBC production

Question 20

33% kidney function

Answer 20

Concentrating function is impaired
<1.025-1.030 in dogs
<1.035 and 1.040 in cats

Question 21

25% of kidney function

Answer 21

Impaired kidney function and azotemic

Question 22

Primary Renal azotemia

Answer 22

Elevation or buildup of nitrogenous products (BUN< creatinine, SDMA) in the blood due to ↓ kidney function
Ex: acute and chronic kidney disease

Question 23

Kidney failure

Answer 23

Failure to maintain homeostasis, destruction of 3/4 of functional mass of both kidneys
Creatinine >1.5 mg/dl or BUN >33mg/dl
SG: 1.008-1.030 (1.035 in cats)

Question 24

T/F: When the creatinine is almost normal (little ↑), there’s a big drop in GFR

Answer 24

TRUE
important for kidney disease

Question 25

T/F: Large reductions of high creatinine minimally affect GFR

Answer 25

TRUE *kidney function not affected much*

Question 26

Prerenal azotemia

Answer 26

↑ creatinine and BUN SG adequate: >1.030 in dogs and >1.035 in cats

Question 27

Renal Azotemia

Answer 27

↑ creatinine and BUN SG inappropriate: 1.007-1.029 in dogs and 1.007-1.034 in cats Kidney not functioning well

Question 28

Postrenal azotemia

Answer 28

↑ creatinine and BUN SG variable Detection of urinary obstruction or rupture (clinically sick)

Question 29

All manifestations of disease are the result of two processes:

Answer 29

1. What the disease induces 2. The body's compensatory response

Question 30

Disease induced → body's response

Answer 30

Polyuria → polydipsia Polydipsia → polyuria Trauma → inflammation Systemic infection → fever Hypoxemia → tachypnea

Question 31

If chronic kidney disease is driving PU/PD, what happens to serum sodium? (↓ 25% kidney function/ azotemia)

Answer 31

Primary polyuria Serum [Na+] is higher because more water is urinated out first (hemoconcentrated)

Question 32

If hyper-anxiety is driving PU/PD, what happens to the serum sodium?

Answer 32

Primary polydipsia Diluting out the components in your blood Serum [Na+] is lower because more water consumed

Question 33

Proteinuria

Answer 33

Lab abnormality implying urine protein excretion in excess

Question 34

Pre-renal proteinuria

Answer 34

Detected if ↑ concentration of small proteins in blood, functional (Hb, myoglobin)

Question 35

When does pre-renal proteinuria happen?

Answer 35

Intravascular hemolysis Myoglobinemia Myeloma

Question 36

Pre-renal proteinuria urinalysis

Answer 36

Red color High protein (could be 2 or 3 +)

Question 37

Renal proteinuria

Answer 37

Glomerular (can lead to renal failure, chronic)- albumin Renal tubular disease and interesital disease (mild and not as common)

Question 38

Renal proteinuria urinalysis

Answer 38

Protein in the urine (1+ ...) No RBCs and WBCs Low SG *run urine protein creatinine ratio*

Question 39

Post-renal proteinuria

Answer 39

Ureter, bladder, urethra disease Urinary obstruction or leakage in the body Most common, doesn't relate to kidney disease

Question 40

Post-renal proteinuria urinalysis

Answer 40

Protein (norm) Color: red TNTC WBCs, RBCs, and epithelial cells

Question 41

Tests for proteinuria

Answer 41

Urine dipstick (urinalysis- albumin) Urine protein to creatinine ratio (renal proteinuria) Sulfasalycyclic acid turbidity and electrophoresis)

Question 42

Components to uroliths (urinary stones)

Answer 42

Nidus (Ca++ oxalate how stone formed)* Stone Shell Surface crystals

Question 43

Why stones form?

Answer 43

Precipitation crystallization** Matrix nucleation Crystallization inhibition Homogenous or heterogenous nucleation

Question 44

Homogenous or heterogenous nucleation

Answer 44

Homo: requires energy and forms initiation of crystal Hetero: Something initiates it

Question 45

Struvite stones

Answer 45

Magnesium amonium phosphate pH causes stone to from (↑ urine alkalinity) Acidify urine to reverse stones

Question 46

What causes urolith formation?

Answer 46

Hepatic disease UTI Genetic abnormalities Hypercalemic disorders Altered pH Vitamin and Mineral Excesses in Diet Sequela to drug admin Hypovolemic disorders