Diuretics pt. 1 (Exam III) Flashcards

1
Q

Differentiate a diuretic from a natriuretic.

A

Diuretic = ↑ Urination
Natriuretic = ↑ Na⁺ secretion → ↑ H₂O secretion.

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2
Q

What’s the name of a drug that specifically targets H₂O loss?

A

Aquaretic

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3
Q

What are the end goals for diuretics in general?

A

↓ Blood volume = ↓ HTN
or ↓ edema

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4
Q

What component of our blood buffer system can be lost through diuretic use?
What can occur when imbalances of this component occur?

A
  • HCO₃⁻
  • Metabolic Acidosis/Alkalosis
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5
Q

What are the 5 classes of diuretics?

A
  1. Carbonic Anhydrase Inhibitors
  2. Loop Diuretics
  3. Thiazides
  4. K⁺-Sparing Diuretics
  5. H₂O Excretion Altering Agents
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6
Q

How many nephrons does a normal human kidney contain?

A

800,000 - 1,000,000

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7
Q

What are the 3 prinicipal activities of nephrons in producing urine?

A
  1. Filtration
  2. Reabsorption
  3. Secretion
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8
Q

The Glomerulus, Bowman’s Capsule, Proximal Convoluted Tubule (PCT) and Distal Convoluted Tubule (DCT) are all located in what major region of the kidney?

A

Renal Cortex

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9
Q

Differentiate Glomerulus and Bowman’s Capsule.

A
  • Glomerulus = capillary network inside Bowman’s Capsule
  • Bowman’s Capsule = Nephron tissue surrounding glomerulus. (collects filtrate from glomerulus)
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10
Q

Where is the first space where blood “interacts” with urine and where the majority of fluid absorption into the urinary system occurs?

A

Glomerulus and Bowman’s Capsule

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11
Q

What are the components of the renal corpuscle?

A

Glomerulus and Bowman’s Capsule

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12
Q

What are the three components of the renal tubule?

A
  1. Proximal Convoluted Tubule (PCT)
  2. Loop of Henle
  3. Distal Convoluted Tubule (DCT)
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13
Q

What is the name of the area where afferent and efferent arterioles enter/exit the renal corpuscle?

A

Vascular Pole

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14
Q

Dilation of afferent arterioles results in _________.

A

↑ GFR

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15
Q

What is the urinary pole?

A

Area where filtrate in Bowman’s Capsule enters the PCT.

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16
Q

The capillary networks that wraps around the PCT and DCT is called what?

A

Peritubular Capillaries

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17
Q

The capillary network that wraps around the Loop of Henle is known as what?

A

Vasa Recta

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18
Q

How much of our urinary filtrate is produced in the Bowman’s Capsule?

A

100%

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19
Q

How much of filtrate is reabsorbed in the PCT?

A

80%

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20
Q

How much of filtrate is reabsorbed in the Loop of Henle?

A

6%

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21
Q

How much of filtrate is reabsorbed in the DCT?

A

9%

22
Q

How much of filtrate is reabsorbed in the Collecting Tubule?

A

4%

23
Q

For every 100ml of blood that is filtered, how much urine is created?

A

1ml of urine

24
Q

What are the three components of the Juxtaglomerular Apparatus?

A
  1. Macula Densa
  2. Juxtaglomerular Cells
  3. Extraglomerular Mesanginal Cells
25
Q

Where is the Juxtaglomerular Apparatus located?

A

Vascular Pole of the Renal Corpuscle.

26
Q

Where are the Macula Densa cells located? What other structure do they touch?

A
  • Ascending Limb of the Loop of Henle
  • Juxtaglomerular cells of the afferent arteriole
27
Q

What do the Macula Densa cells do?

A
  1. Monitor Osmolality and fluid volume of DCT
  2. Transmit signals to JG cells.
28
Q

Where are our juxtaglomerular cells located?
What type of cell are they?
What do they do in response to stimuli?

A
  • Afferent arteriole of the renal corpuscle.
  • Modified smooth muscle cell
  • Synthesize Renin
29
Q

Though the PCT reabsorbs many different parts of the filtrate, in lecture we were told to focus on two specific things. What are these two things that the PCT reabsorbs?

A
  1. NaHCO₃
  2. NaCl
30
Q

What is the mechanism of action of Carbonic Anhydrase Inhibitors?

A

Blocking reabsorption of NaHCO₃ in the PCT.

31
Q

How does caffeine affect urine output?

A
  1. Caffeine weakly blocks adenosine receptors in PCT
  2. Blocked adenosine receptors = ↑ UO
32
Q

What does adenosine binding to receptors in the PCT do?

A

Adenosine binding in the PCT will ↓ UO.

(Because adenosine presence means we need to conserve energy, creating urine is energy intensive.)

33
Q

Which transporter(s) starts the cycle in the PCT to preserve HCO₃⁻ ?

How does it start the above stated cycle?

A

NHE3 Apical Surface Transporter

NHE3 exchanges Na⁺ for H⁺

34
Q

In the HCO₃⁻ Retention cycle of the PCT, what occurs to the H⁺ once its placed into the urine by the NHE3 transporter?

A

H⁺ binds to HCO₃⁻ forming H₂CO₃

35
Q

What enzyme cleaves H₂CO₃ into CO₂ + O₂ ?

What occurs if this enzyme is inhibited?

A

CA (Carbonic Anhydrase)

  • HCO₃⁻ is lost to the urine
  • NHE3 affected = Na⁺ loss
36
Q

What is the only CA Inhibitor still in use?

A

Acetazolamide

37
Q

What are Acetazolamides effects on:
1. NaCl
2. NaHCO₃
3. K⁺
4. pH

A
  1. ↓ serum NaCl
  2. ↓↓↓ NaHCO₃
  3. ↓ K⁺
  4. Metabolic Acidosis ( HCO₃⁻ loss )
38
Q

What is normal serum osmolality?

What is the osmalality in the deepest parts of the renal medulla?

A

300 mOsm/kg

1200 mOsm/kg

39
Q

What is the osmolality of the renal cortex?

A

Variable: 100-300 mOsm/kg

40
Q

Which drug is an impermeable solute that works by drawing H₂O to it throughout the nephron?

When is this drug reabsorbed from the urine into the blood stream?

A

Mannitol

Mannitol does not get reabsorbed.

41
Q

What does the S2 segment of the PCT have in comparison to other parts of the nephron?

A

Protein Transporters

42
Q

What occurs in the descending limb of the Loop of Henle?

What characteristic does the tissue have that makes this occur here?

A

H₂O reabsorption

Hypertonic medullary interstitium

43
Q

Which portion of the Loop of Henle is impermeable to H₂O ?

A

Thick Ascending Limb (TIL)

44
Q

How are Mg⁺⁺ and Ca⁺⁺ reabsorbed in the Thick Ascending Limb?

A
  1. K⁺ is moved from ICF to urine.
  2. K⁺ excess makes urine + charged.
  3. Positively (+) charged urine drives Mg⁺⁺ and Ca⁺⁺ through pericellular route to blood interstitium.
45
Q

Would the loop of Henle have a relatively low or high osmolality?

A

↑ Osmolality

46
Q

Which transporter moves NaCl and K⁺ into the ICF of the Thick Ascending Limb?

A

NKCC2

47
Q

Which diuretic class inhibits NaCl reabsorption in the Thick Ascending Limb (TAL) ?

Which transporter is blocked to achieve this effect?

A

Loop Diuretics (Furosemide)

NKCC2

48
Q

Which diuretics can’t be used if one is allergic to -sulfa drugs?
What might be a good alternative to this class if a -sulfa allergy is present?

A

Loop Diuretics (Furosemide, etc.)

Ethacrynic Acid (Loop diuretic w/ no sulfa)

49
Q

Which diuretic class is useful as it is the most efficacious class and also does not cause metabolic acidosis?

A

Loop Diuretics

50
Q

How does furosemide increase secretion (loss through urine) of Mg⁺⁺ and Ca⁺⁺ ?

A
  1. ↓ NaCl reabsorption
  2. K⁺ ICF concentration ↓
  3. Urine + decreases
  4. No + urine = ↓ movement of Mg⁺⁺ and Ca⁺⁺
51
Q

What type of bodily pH might result from Loop diuretic administration?

Is there HCO₃⁻ loss from this drug class?

A

Slight Alkalosis

No HCO₃⁻ loss