LMP301 Lecture 3: Fluid Balance Flashcards Preview

LMP301 > LMP301 Lecture 3: Fluid Balance > Flashcards

Flashcards in LMP301 Lecture 3: Fluid Balance Deck (135)
0

ECF can be subdivided into...

- Plasma
- Interstitial fluid (ISF)

1

How much ICF is there?

28L

2

How much ECF is there?

14L

3

How much plasma is there?

3.5L

4

How much ISF is there?

10.5L

5

ACE inhibitor = ?

angiotensin converting enzyme inhibitor

6

What are ACE inhibitors used for and how do they work?

Used for hypertension
Work by dilating blood vessels

7

What are the common electrolytes measured?

Na+
K+
Bicarbonate
Ca++
Potassium phosphate

8

Where are electrolytes measured from?

Plasma

9

Plasma and electrolytes are most abundant in...

ICF

10

Is it harder to do ECF or ICF measurement?

ICF

11

What are extracellular ions?

Na+
Cl-
HCO3-
Ca++

12

What are intracellular ions?

K+
PO4
Anions

13

Define: concentration

amount of solute in a solvent

14

Define: osmolality

amount of solute particles in a solvent (weight)

mmol/kg
mOsm/kg

15

How to estimate osmolality?

Measure the most abundant solutes:

2[Na+] & [Glucose] & [Urea]

16

Define: osmolarity

amount of solute particles in 1kg of water (WATER IS SOLVENT)

17

When measuring dilute aqueous solutions, the appropriate unit is...concentration / osmolality / osmolarity

osmolarity

18

One weakness of concentration measurements

Must take into account total volume of solvent (dehydrated might affect measurement of electrolytes)

19

Osmolarity is a passive / active process?

passive

20

Define: oncotic pressure

Pressure in the capillaries

Walls of capillaries act as semi-permeable membrane, and proteins pull water into plasma.

21

Define: hydrostatic pressure

Pressure exerted by the heart when it pumps

Pushes fluid in vessels into ISF.

22

Oncotic pressure is balanced by...

Hydrostatic pressure

23

Hydrostatic pressure is balanced by...

Oncotic pressure

24

What might affect oncotic pressure?

- Injury: cause proteins in plasma to leak out

25

Typical input of water?

0.5 - 5L per day

26

Amount of output of water through renal processes?

0.5 - 4L per day

27

Amount of output of water through GI tract?

< 0.1 L per day

28

Amount of output of water through insensible loss?

0.5 - 1L per day

29

Define: insensible loss

Loss of fluid through sweat & respiration

30

Most of body fluids are lost through...

Renal processes (kidney)

31

Define: dehydration

Releasing more fluid than you're consuming

32

Define: overhydration

Taking in more fluid than you're releasing

33

Define: polyuria

A lot of pee

34

Define: polydipsia

Consuming a lot of water

35

Define: oligouria

Small amount of urine output

36

Define: anuria

no urine output

37

What medical term falls under dehydration?

polyuria

38

What medical terms fall under overhydration?

- polydipsia
- oligouria
- anuria

39

Features of dehydration (physical)

- increased pulse
- dry mucous membranes
- soft / sunken eyeballs
- decrease bld pressure
- decreased urine
- decreased skin turgor

40

Biochemical signs of dehydration

- increased plasma sodium
- increased bld urea
- increased hematocrit

41

Define: hematocrit

volume of RBC in blood

42

What is edema?

Accumulation of fluid in the ISF of your cells

43

Edema is a symptom of...

overhydration

44

Features of overhydration (physical)

- normal pulse
- normal mucous memb
- normal eyeballs
- normal / incr bld pressure
- normal / decr urine
- incr skin turgor

45

Symptoms of overhydration (biochem)?

- normal / decr plasma sodium
- normal / decr bld urea
- normal / decr hematocrit

46

How is water regulated in the body?

1. Control osmolality
2. Control bld volume

47

Which is the direct route of water regulation?

control of osmolality

48

which is the indirect route of water regulation?

control of bld volume

49

How is osmolality controlled in the body? (via ADH)

1. Hypothalamus senses bld osmolality
2. Hypothalamus tells p. pituitary to make ADH
3. ADH goes to kidney collecting tubules
4. Kidney absorbs more water

50

more Na+ in the bld indicates... (in terms of osmolality)

higher bld osmolality

51

Less Na+ in the bld indicates ____ osmolality

lower

52

How is osmolality controlled in the body?

1. ADH
2. Thirst

53

How is osmolality controlled in the body? (Thirst)

1. Hypothalamus tells you to drink water
2. When homeostasis is reached, hypothalamus tells p. pituitary to stop secreting ADH

54

SIADH

syndrome of inappropriate ADH secretion

55

What does SIADH do?

Secrete too much ADH

Too much water reabsorbed

56

DI

Diabetes Insipidus

57

What is the symptoms of DI?

Not enough ADH secreted

Water not reabsorbed-> dehydration

58

How is sodium stored in the body?

25% in bones / tissues
75% in ECF

59

How is sodium regulated?

1. Aldosterone
2. ANP

60

Aldosterone is secreted by...

adrenal gland

61

Aldosterone is secreted in response to...

ATII (angiotensin II)

62

What does aldosterone cause?

Na+ resorption in kidney (but H+ and K+ secreted as a result)

63

ANP

atrial naturetic peptide

64

ANP is secreted by...

atria of heart

65

What stimulates ANP secretion?

Amount of stretch of tissues in the heart (incr. stretch stimulates release)

66

ANP causes...

Na+ secretion in kidney (also get rid of water because it carries the Na+)

67

How is bld volume controlled?

1. Renin (from kidney) converts angiotensinogen -> ATI
2. ACE converts ATI -> ATII
3. ATII causes vasoconstriction, Na+ resorption in kidney, aldosterone release
4. Aldosterone stimulate Na resorption

68

What is renin?

enzyme secreted by kidney

69

What stimulates renin secretion?

low blood pressure

70

What converts ATI -> ATII?

ACE (angiotensin converting enzyme)

71

Aldosterone increases plasma Na+ at the expense of...

K+

72

What are the effects of aldosterone on K+?

- Decrease bld K+
- Increase urine K+

73

What is the effect of aldosterone on Na+?

- Increase bld Na+
- Decr. urine Na+

74

Define: hypernatremia

Increased serum [Na+]

75

What is the value for hypernatremia?

>145 mmol/L

76

What are some causes of hypernatremia?

1. Decr. body water
2. Water loss > Na+ loss (hypotonic)
3. Excess Na+ intake

77

What causes decreased body water?

1. Decreased water intake
2. Excess water loss (DI)

78

What causes water loss > Na+ loss?

.

79

What is osmotic diuresis?

Things that draw water out along with it

e.g. excretion of glucose in urine will cause water to also be excreted

80

What causes excess Na+ intake?

1. Diet
2. IV
3. Hyperaldosteronism (Conn's syndrome, Cushing's syndrome)

81

Conn's syndrome

too much aldosterone

82

Cushing's syndrome

Too much cortisol
(act like aldosterone in terms of Na+ reabsorption)

83

What is hyponatremia?

Low serum [Na+]

84

What causes hyponatremia?

1. Increased water in body
2. Na+ loss > water loss (hypertonic urine)
3. Decreased Na+ in body

85

What causes increased water in body?

1. excess water intake
2. SIADH
3. Renal failure
4. Edema (nephrotic syndrome, heart failure)
5. IV

86

2 things that cause edema

1. Nephrotic syndrome
2. Heart failure

87

What is nephrotic syndrome?

Non-specific kidney disease

???

88

What causes Na+ loss > water loss in urine?

1. Diarrhea
2. Sweating
3. Burns
4. Diuretics

89

What causes decreased body Na+?

1. Adrenal insufficiency / not enough aldosterone (Addison's disease)

90

Addison's disease

Too little aldosterone

91

Which symptom of hyponatremia & hypernatremia is the same?

Na+ loss > or < than water loss

(Sweating, diarrhea)

92

What happens if the kidney can't respond to aldosterone?

Problems with Na+ reabsorption

93

What does kidney disease cause?

Kidney can't respond to aldosterone

94

What does diuresis cause?

kidney secreting more Na+ / secreting more Na+ and K+

-> diuretics

95

What is the effect of adrenal disease?

Too much / little production of aldosterone

96

ADH and aldosterone have the [same / different] effects in terms of Na+?

Same

97

How does the body respond to edema?

1. Release aldosterone
2. Release ADH

98

Edema causes a ___ in effective circulating volume

decrease

99

Things that may cause edema:

1. heart failure
2. hypoalbuminemia

100

How does heart failure contribute to edema?

Fluid in vessels accumulate instead of pumped by the heart-> goes into ISF

101

How does hypoalbuminemia contribute to edema?

Less albumin -> less oncotic pressure -> more fluid in ISF

102

How to examine Na+ disorders?

1. Examine serum [Na+] (hypo / hypernatremia)
2. Examine bld volume (de / overhydrated)
3. Examine input / output of water & Na+
4. Consider organ dysfunction (kidney, p. pituitary, adrenal gland)

103

Aldosterone is secreted by...

adrenal gland

104

IV

Intravenous Fluid Therapy

105

What is IV used for?

correct imbalances in the body

106

IV can contain...

1. 5% dextrose
2. 0.9% saline (NaCl)
3. Plasma

107

Dextrose in IV

- Correct overall dehydration (ECF & ICF)
- Isotonic w/ plasma, glucose quickly metabolized so only water remains

108

Why can't water be directly given as IV to rehydrate someone?

Water is very hypotonic, and will cause cells to explode

109

Saline (NaCl) in IV

- For dehydration in ECF
- Isotonic to plasma

110

Plasma in IV

- Correct dehydration in vessels (vascular compartment)
- Given by donor
- Contains electrolytes & protein
- Protein -> oncotic pressure -> more water in vessels

111

Role of potassium?

1. Maintain membrane potential
2. Heart beat & contraction
3. Acid-base balance

112

What role does K+ play in acidosis?

1. H+ may get in cells
2. K+ has same charge-> pushed out of cells int vessels
3. High K+ in bld = hyperkalemia

113

Severe kyperkalemia causes...

Irregular heart beat
Death

114

How is K+ stored?

99% in ICF
1-2% in ECF

115

Main loss of K+?

Renal

116

What causes hyperkalemia?

1. Acidosis
2. Cells break
3. Excess intake
4. Renal failure
5. Mineralocorticoid deficiency

117

What is the cutoff for hyperkalemia?

> 6 mmol/L

118

How does mineraldocorticoid deficiency lead to hyperkalemia?

1. Adrenal gland doesn't produce aldosterone
2. Drugs that inhibit aldosterone production

119

What is the cutoff for hyponatremia?

< 135 mmol/L

120

What is the cutoff for hypokalemia?

< 3 mmol/L

121

What causes hypokalemia?

1. alkalosis
2. renal loss
3. drugs
4. gastrointestinal loss (diarrhea & vomiting)

122

Define: alkalosis

Bld pH is basic

123

How does alkalosis affect K+?

K+ goes into cells -> hypokalemia

124

[More / less] aldosterone causes hypokalemia

More

125

What drugs causes hypokalemia?

Thiazide diuretics
Corticosteroids

126

What does thiazide diuretics do?

Excrete Na+ and K+

127

What is pseudohyperkalemia?

Falsely high plasma K+

128

What leads to pseudohyperkalemia?

1. Hemolysis during venipuncture
2. Too long tourniquet
3. Disease (too much WBC, platelets)

129

What is released during clotting?

K+

130

What is tourniquet?

Tying off the arm when getting a shot

131

What is venipuncture?

getting a shot

132

Renin and aldosterone are sensitive to ____

Posture

133

What is something you have to make sure when doing a recumbent sample?

Compare with the right range (recumbent range)

134

Recumbent

Sample lying down