Acid Base And Fluids

Question 0

Which azotemia causes BUN increases more than serum creatinine andthere is an increased BUN/creatinine ratio (>20:1)?

Answer 0

Prerenal azotemia like in hypovolemia

Question 1

Vasodilation of renal arterioles, which leads to an increase in RBF, is produced by

Answer 1

prostaglandins E2 and I2, bradykinin, nitric oxide, and dopamine

Question 2

reabsorbs two-thirds, or 67%, of the filtered Na+ and H2O, more than any other part of thenephron.
■ is the site of glomerulotubular balance.

Answer 2

Proximal tubule

Question 3

reabsorbs 25% of the filtered Na+.
■ contains a Na+–K+–2Cl– cotransporter in the luminal membrane.
■ is the site of action of the loop diuretics (furosemide, ethacrynic acid, bumetanide),which inhibit the Na+−K+−2Cl− cotransporter.
■ is impermeable to water. Thus, NaCl is reabsorbed without water. As a result, tubular fluid+
[Na ] and tubular fluid osmolarity decrease to less than their concentrations in plasma(i.e., TF/PNa+ and TF/Posm

Answer 3

Thick ascending limb of henle

Question 4

reabsorbs NaCl by a Na+-Cl- cotransporter.■ is the site of action of thiazide diuretics.

Answer 4

Cortical diluting segment or early distal tubule

Question 5

reabsorb Na+ and H2O.
■ secrete K+.
■ Aldosterone increases Na+ reabsorption and increases K+ secretion. Like othersteroid hormones, the action of aldosterone takes several hours to develop+
because new protein synthesis of Na channels (ENaC) is required. About 2% ofoverall Na
+
reabsorption is affected by aldosterone.
■ Antidiuretic hormone (ADH) increases H2O permeability by directing the insertion ofH2O channels in the luminal membrane. In the absence of ADH, the principalcells are virtually impermeable to water.
■ K+-sparing diuretics (spironolactone, triamterene, amiloride) decrease K+ secretion

Answer 5

Principal cells of distal tubule and collecting ducts

Question 6

Causes of hyperkalemia?

Answer 6

Insulin deficiency

β-Adrenergic antagonists

Acidosis (exchange of extracellular 
\+
H
\+
for intracellular K )

Hyperosmolarity (H2O flows out of +
the cell; K diffuses out with H2O)

Inhibitors of Na –K
pump (e.g., digitalis) +
[when pump is blocked, K
up into cells]

Exercise

Cell lysis

Question 7

T or F.

Acidosis decreases K secretion

Answer 7

True

Question 8

Furosemide: treat hypercalcemia
Thiazide: treat hypercalciuria

Answer 8

True!

Question 9

↓ plasma [Ca2+]
↑ Fast
Basolateral
receptor
Adenylate cyclase
cAMP →urine
↓ phosphate reabsorption
(proximal tubule)
↑ Ca2+ reabsorption
(distal tubule)
Stimulates 1α-hydroxylase(proximal tubule)

Answer 9

PTH

Question 10

↑ Na+−H+ exchange and−HCO3 reabsorption

proximal tubule

Answer 10

Angiotensin II

Question 11

The major extracellular buffer is _____ which is produced from CO2 and H2O.

Answer 11

HCO3-

Question 12

most important as a urinary buffer, titatable acid

Answer 12

Phosphate

Question 13

ECF volume contraction results in increased HCO3 reabsorption

Answer 13

yes! Contraction alkalosis

Question 14

Hyperkalemia inhibits NH3+ synthesis, which produces a decrease in H excretion as NH4. The condition is noted in?

Answer 14

[type 4 renal tubular acidosis (RTA)]

Question 15

causes of respiratory alkalosis

Answer 15

Pneumonia; pulmonary embolusHigh altitude
Psychogenic
Salicylate intoxication

Question 16

Symptoms of hypocalcemia (e.g., tingling, numbness, muscle spasms) may occurbecause H+ and Ca2+ compete for binding sites on plasma proteins. Decreased [H ]causes increased protein binding of Ca2+ and decreased free ionized Ca2+. T or F?

Answer 16

true

Question 17

↑ K+ excretion (↑ distal
tubule flow rate)
↑ Ca2+ excretion (treat 
hypercalcemia)
↓ ability to concentrate urine 
(↓ corticopapillary gradient)↓ ability to dilute urine
(inhibition of diluting
segment)
What is the diuretic being described?

Answer 17

Loop diuretics like furosemide