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Flashcards in Cardio V Deck (69):
1

What is the most metabolically active part of the nephron? Second?

Proximal convoluted tubule

Thick ascending

2

What is the order of the nephron? (7)

Proximal
Thick descending
Thin Descending
Think Ascending
Think ascending
Distal convoluted
Collecting duct

3

Where is most of the Na/potassium in the renal tubule reabsorbed? Is this regulated?

Proximal convoluted tubule

Not regulated

4

What is the primary process that is occurring in the thin descending loop of henle?

Water reabsorption passively

5

What is the primary process that is occurring in the thick ascending loop of henle?

Reabsorption of electrolytes, no water

6

What is the primary process that is occurring in the distal convoluted tubule?

Na Cl reabsorption--No K

7

What is the primary process that is occurring in the collecting duct?

NaCl reabsorption

8

Where does ADH work?

Collecting duct

9

What part of the tubule is regulated for K uptake?

Distal convoluted tubule

10

What are the processes that are occurring at the glomerulus?

Non

11

Where is glucose reabsorbed in the nephron?

Proximal convoluted tubule

12

What is the relative water permeability of the distal convoluted tubule?

Very low

13

What is the primary transporter at the: glomerulus?

None

14

What is the primary transporter at the: PCT?

Na/H exchanger
Carbonic anhydrase

15

What is the primary transporter at the: Straight segments of the proximal tubule

Acid and base transporters

16

What is the primary transporter at the: thin descending loop

aquaporins

17

What is the primary transporter at the: thick ascending

Na/K/Cl

18

What is the primary transporter at the: DCT

Na/Cl

19

What is the primary transporter at the: cortical collecting tubule

Na channels
K channels
Aquaporins

20

What is the primary transporter at the: medullary collecting duct

Aquaporins

21

What happens when there is an increase in [Na] of the filtrate when it gets to the distal convoluted tubule?

Increased K excretion

22

What is the prototypical carbonic anhydrase inhibitor?

Acetazolamide

23

What is carbonic anhydrase needed for in the kidney? Where is it found?

HCO3 reabsorption in the proximal convoluted tubule

24

What is the exchanger protein in the proximal convoluted tubule, that is responsible for the reuptake of Na? Which side of the tubular cell is this found on?

Na/H exchanger

Both lumenal and basolateral--pumps H+ from circulation all the way out to the tubule in exchange for Na

25

What happens to the H+ that is secreted into the lumen of the renal tubule?

Combines with HCO3- to form bicarb

26

What happens to the bicarbonate in the nephron lumen?

carbonic anhydrase converts it to CO2 and H2O. CO2 then goes back into the tubule cell, where it forms H2CO3 again in the cell

27

Inhibition of carbonic anhydrase causes a major loss of what chemical in the urine? What chemical is maintained in the tubule? What is the effect of this on the circulation?

HCO3- lost
NH4 maintained
metabolic acidosis

28

What happens when there is decreased HCO3 absorption by the PCT? What does this cause?

Increased solute delivery to the macula densa, increasing afferent arteriolar resistance, and decreasing renal blood flow

29

What is tubular glomerular feedback?

Increased solute delivery to the macula densa leads to increased afferent arteriolar resistance, and low GFR

30

What happens to Na/Cl when HCO3 flows out of the tubule?

Na and Cl follow

31

Why is it that when carbonic anhydrase is inhibited, there is an increase in K excretion?

Loss of HCO3 increases Na/Cl excretion. Higher Na in the filtrate will increase K excretion

32

Why are carbonic anhydrase inhibitors used in the treatment of glaucoma?

CA is present in the ciliary body, and plays a role in aqueous humor production

33

What is the most common indication for carbonic anhydrase inhibitors?

glaucoma

34

Why is carbonic anhydrase used in the treatment of acute mountain sickness?

CA is present in the choroid plexus. By decreasing CSF formation, and decreasing the pH of the CSF and brain, CA can increase ventilation and diminish symptoms of mountain sickness

35

Why is carbonic anhydrase used in the treatment of gout or drug clearance?

Increased excretion of uric acid in alkaline urine caused by CA inhibitors

36

Why is carbonic anhydrase used in the treatment of edema states?

Diuretic aspect

37

Chronic reduction of HCO3 stores by CA inhibitors leads to what?

Hyperchloremic metabolic acidosis

38

How does CA inhibitors lead to renal stones?

Increased excretion of Na leads to the build up of Ca salts

39

How does renal K wasting occur with CA inhibitors? How can this effect be counteracted?

Increasing the lumen negative electrical potential in the collecting tubule enhances K excretion


Administer KCl

40

What diseases contraindicate CA inhibitors? Why?

Cirrhosis, hyperammonemia, and hepatic encephalopathy, because NH4 levels are increased with CA inhibitor

41

What is the MOA of osmotic diuretics?

Osmotic agents that stay in the filtrate and cause water to be pulled into it

42

What are the four osmotic diuretics?

Mannitol
Glycerin
Isosorbide
Urea

43

What is the main site of action of osmotic diuretics?

Thin loop of henle

44

Why is there an increased loss of K with osmotic diuretics?

Increased distal flow in the distal tubule stimulates K secretion

45

How do osmotic diuretics reduce acute tubular necrosis?

maintain flow through the tubule
2. Remove obstructing tubular casts
3. Dilution of nephrotoxic substances
4. Reduction of swelling of tubular elements

46

Why are osmotic diuretics used in the treatment of cerebral edema?

Alter starling's forces to pull water out of cells

47

What is dialysis disequilibrium syndrome?

Too rapid of a removal of solutes from ECF by hemodialysis results in a reduction of osmolality of the ECF, causing a fluid shift into the intracellular compartment

48

How do osmotic diuretics help in dialysis disequilibrium syndrome?

Osmotic diuretics increase the osmolality of the extracellular fluid compartment and thereby shift water back into the extracellular compartment

49

How do osmotic diuretics help with acute attacks of glaucoma?

Increasing osmotic pressure of the plasma, extract water from the eye

50

What are the three adverse effects of osmotic diuretics?

Expand extracellular fluid volume
Hyponatremia
Hypernatremia

51

What pts are particularly at risk for expansion of ECF volume d/t osmotic diuretics?

heart failure

52

How do osmotic diuretics cause hyponatremia?

Increased extraction of water

53

How do osmotic diuretics cause hypernatremia?

Loss of water in excess of electrolytes

54

Why should pts with impaired liver function not be given urea as an osmotic diuretic?

Increases ammonia level

55

Why should pts with an active cranial bleed not be given mannitol or urea?

Diuretic will leak out of the intravascular compartment

56

Why should hyperglycemic pts not be given glycerin?

Glycerin can be metabolized and cause hyperglycemia

57

What is the MOA of loop diuretics?

Selectively inhibit NaCl reabsorption in the thick ascending loop of henle (NKCC inhibition)

58

Why are loop diuretics so efficacious?

huge absorptive capacity of NaCl in the tubules

59

What are the three loop diuretics?

1. Furosemide
2. Bumetanide
3. Ethacrynic acid

60

What is the effect of loop diuretics on the veins?

Decreased venous pressure

61

Why is it that you lose Ca and Mg with loop diuretics?

Decreasing the lumen positive potential that promotes Ca/Mg reabsorption

62

Why are loop diuretics used for acute pulmonary edema?

Rapid increase in venous capacity and fast natriuresis relieved pressure on the heart

63

Why are loop diuretics used to treat chronic congestive heart failure?

Minimizes pulmonary and venous congestion

64

Why are loop diuretics used for nephrotic syndrome?

Loop diuretics are the only drugs that are able to draw off fluid from the kidneys

65

What are loop diuretics used in liver cirrhosis?

Draw of edema/ascites caused by liver failure

66

Why are loop diuretics used in drug overdoses?

Induce a forced diuresis for rapid renal elimination of the offending drug

67

What are loop diuretics used in hypercalcemia?

Will maintain Ca in the lumen of the nephron, causing loss in the urine

68

Why are loop diuretics used to treat hyponatremia?

they interfere with the kidney's capacity to produce concentrated urine.

Using hypertonic saline + loop diuretics

69

What is THE major adverse effect of loop diuretics?

Hypokalemia