Lecture 12: Renal Physiology (Rogers) Flashcards Preview

Year 1: 09. CPR Exam 2 > Lecture 12: Renal Physiology (Rogers) > Flashcards

Flashcards in Lecture 12: Renal Physiology (Rogers) Deck (43)
Loading flashcards...
1
Q

In the body, how is water distributed?

A

⅔ of water in ICF

⅓ of water in ECF

2
Q

In the ECF how, is water distributed?

A

80% interstitial fluid

20% plasma (capillary wall)

3
Q

What is the 60-40-20 rule?

A

60% of body weight is body water
40% of body weight is body water in ICF
20% of body weight is body water in ECF

4
Q

How do constituents between the ICF and external world interact with each other?

A

Through ECF

-water always enters ECF compartment first and fluid leaves body via ECF

5
Q

Describe “third spacing”

A

Most fluids should be in intravascular, intracellular, or interstitial spaces

  • However, fluid can shift into nonfunctional areas of cells: b/t tissues and organs of abdomen, ascites, areas around pulmonary edema
  • problematic
6
Q

Why must ECF volume be closely regulated?

A

To maintain blood pressure

  • salt balance
  • prevent shrinking and swelling of cells
7
Q

What ions are in higher concentration in the ECF?

A

Sodium
Chloride
Bicarbonate

8
Q

What ions are in higher concentration in the ICF?

A

Potassium

Phosphate

9
Q

What is an electrolyte?

A

Solutes that dissociate into ions

  • have higher osmotic power
  • greater ability to cause fluid shift
10
Q

What can cause polyuria?

A

Increased intake of fluids
Increased GFR
Increased output of solutes
Inability of kidney to reabsorb water

11
Q

Regarding polyuria, what is the difference between water and solute diuresis?

A

Water diuresis: increased water excretion w/o corresponding increase in salt excretion

Solute diuresis: increased water excretion with corresponding increase in salt excretion

12
Q

What can cause oliguria?

A

Dehydration
Blood loss
Diarrhea
Kidney disease

13
Q

What can cause anuria?

A

Kidney failure

Obstruction

14
Q

How do you calculate free water clearance?

A

Clearance = Urine Flow Rate - [(Urine Osmolarity x Urine Flow Rate) / Plasma Osmolarity]

15
Q

What does it mean if free water clearance is positive?

A

Dilute urine

16
Q

What does it mean if free water clearance is negative?

A

Concentrated urine

17
Q

How is plasma (serum) osmolarity measured?

A

Osmolarity = (Sodium x 2) + (Glucose/18) + (BUN/2.8)

Rough Calculation: 2 x plasma Sodium

18
Q

Describe the Gibbs-Donnan Effect.

A

Unequal distribution of permeant charged ions on either side of a semipermeable membrane

  • favors movement of water into cell
  • only ions can move into cell not proteins
19
Q

What counteracts the Gibbs-Donnan Effect?

A

Na/K+ ATPase pumps

20
Q

What promotes plasma colloid osmotic pressure?

A

Albumin in blood vessels

21
Q

What causes edema?

A

1) Increased net filtration: fluid moving from vascular space to interstitium)
2) Expansion of ECF volume

22
Q

What happens to cells placed in hypertonic solution?

A

Cells will shrink

-water moves out of cell into concentrated solution

23
Q

What happens to cells placed in hypotonic solution?

A

Cells will swell

-water moves into cell from dilute solution

24
Q

Describe crystalloid replacement therapy.

A

Does not cross plasma membrane (in ECF)

  • distributed evenly in ECF
  • common solutes: glucose and NaCl
25
Q

Describe colloid replacement therapy.

A

Large molecules that don’t pass semipermeable membranes

  • remain in intravascular compartment
  • expand intravascular volume by drawing fluids from extravascular spaces via oncotic pressure
26
Q

Describe hypotonic/hyponatremic dehydration.

A

More sodium is lost than water in ECF

  • ICF has greater sodium concentration so water shifts from ECF to ICF (cellular swelling)
  • low serum sodium and serum osmolality
27
Q

Describe hypertonic/hypernatremic dehydration.

A

More water is lost than sodium in ICF

  • ECF has greater sodium concentration so water shifts from ICF to ECF (cellular shrinking)
  • high serum sodium and serum osmolality
28
Q

Describe isosmotic volume contraction.

A

ECF volume: Decrease
ICF volume: Stays same
Osmolality: Stays same

29
Q

What causes isosmotic volume contraction?

A

Hemorrhage
Diarrhea
Vomiting

30
Q

Describe hyperosmotic volume contraction.

A

ECF volume: Decrease
ICF volume: Decreases
Osmolality: Increases

31
Q

What causes hyperosmotic volume contraction?

A
Dehydration
Diabetes Insipidus
Alcoholism
Sweating
Fever
32
Q

Describe hyposmotic volume contraction.

A

ECF volume: Decrease
ICF volume: Increases
Osmolality: Decreases

33
Q

What causes hyposmotic volume contraction?

A

Adrenal insufficiency due to loss of aldosterone

-excessive loss of NaCl in urine

34
Q

Describe isosmotic volume expansion.

A

ECF volume: Increase
ICF volume: Stays same
Osmolality: Stays same

35
Q

What causes isosmotic volume expansion?

A

Isotonic saline injection of NaCl

36
Q

Describe hyperosmotic volume expansion.

A

ECF volume: Increase
ICF volume: Decrease
Osmolality: Increases

37
Q

What causes hyperosmotic volume expansion?

A

High NaCl intake

38
Q

Describe hyposmotic volume expansion.

A

ECF volume: Increase
ICF volume: Increase
Osmolality: Decreases

39
Q

What causes hyposmotic volume expansion?

A

Excessive water-drinking

SIADH

40
Q

People with congestive heart failure retain sodium, ______ ECF volume.

A

People with congestive heart failure retain sodium, INCREASING ECF volume.

41
Q

IF ECF volume is _____, renal NaCl and water excretion are increased.

A

IF ECF volume is EXPANDED, renal NaCl and water excretion are increased.

42
Q

IF ECF volume is _____, renal NaCl and water excretion are reduced.

A

IF ECF volume is CONTRACTED, renal NaCl and water excretion are reduced.

43
Q

Renin is stimulated by ____ blood pressure and by ______ receptor activation.

A

Renin is stimulated by DECREASED blood pressure and by BETA-1 ADRENERGIC receptor activation.