Exam 1: Ch 8 Flashcards Preview

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Flashcards in Exam 1: Ch 8 Deck (107):
1

extracellular fluid

interstitial fluid and plasma

2

mEq

milliequivalents

mEq/L = # of millimoles of charges/L = (mg/L x valence) / AW

mMol/L = # of millimoles of particles/L = (mg/L) / AW = (mEq/l) / valence

3

is osmosis water moves to the side...

with more solute particles

measures as mOsm/L or osmolatity

4

extent of osmotic pressure measured by...

mOsmoles = mMol of non-diffusable particles

5

tonicity

effect of osmotic pressure on a cell

hypotonic solutions have > osmolarity than the cell (swell)

hypertonic solutions have < osmolarity than the cell (shrink)

6

distribution of body fluids

total body water: 60% of weight

intracellular fluid is 2/3, extracellular 1/3

interstitial fluid is 2/3 of extracellular (rest is plasma, and transcellular fluid)

7

transcellular fluid

CSF

peritoneal

pleural

8

capillary filtration pressure (hydrostatic pressure)

BP in a capillary

higher at arterial end than venous end

outward force - pushes blood into interstitium

9

interstitial fluid pressure

low but normally negative

outward force

10

interstitial colloid osmotic pressure

low

outward force

11

capillary colloid osmotic pressure

mostly from proteins (albumin made in liver) in plasma

electrolytes pass freely, no net pressure

inward force - pulls blood back into veins

12

exchange in capillaries

at arterial end out > in, net filtration

at venous end in > out, net reabsorption

fluid or protein not reabsorbed, returns to circulation in lymph

13

edema

swelling caused by excess interstitial fluid

increased capillary filtration (hydrostatic) pressure

more fluid leaves capillary space

usually from increased venous pressure (HF) or increased pressure at arterial end of capillary

14

decreased capillary colloid osmostic pressure

causes edema

less fluid returns to capillary (low albumin)

liver failure or heart disease

15

increased capillary permeability

causes edema

plasma proteins leak out of capillaries

inflammation

16

obstructed lymph flow

causes edema

prevents return of proteins and fluids to circulation

malignancy or surgery

17

assessment/treatment of edema

weight, visual assessment, measurement of affected part

elevate lower extremities, support stockings, diuretics

18

third space fluid accumulation

trapping in transcelular space

peritoneal, pleural, or pericardial

may require drainage

19

TBW of water in lean adults vs. infants

60% lean adults

75-80% in infants

20

how is water taken in and excreted?

intake: drink, food, metabolism

output: urine, respiratory, skin, feces

21

regulation of Na balance

most plentiful extracellular cation

intake: GI

output: renal, skin, lungs

22

RAAA system

renin angiotensin-aldosterone system

lowers sodium concentration, blood volume

BP activates

23

ADH stimulates ____ ____ while Aldosterone stimulates ____ ____

water retention

sodium retention

released together

24

aldo effect and ADH effects

aldo: increased urinary Na retention

ADH: increase thirst --> increase H2O intake & decreased urine water loss

25

if low BP (and low blood volume) due to ECF fluid loss and/or Na loss

renin and angiotensin II released and activated

increase aldo and ADH release

26

if high BP and high blood volume due to excess ECF and or Na gain

increased NP release

decrease aldo and ADH release

27

thirst controlled by

thirst center in hypothalamus, which has osmoreceptors

ADH released by hypothalamus to retain water if ECF is low or there is cellular dehydration

28

hypodipsia

decreased ability to sense thirst

lesions on hypothalamus

29

polydipsia

excessive thirst

CRF or HF from high angiotensin

30

true thirst

accompanies dehydration from blood loss or diabetes mellitus

31

psychogenic polydipsia

compulsive drinking in psychiatric disorders

32

2 ADH disorders

diabetes insipidus

syndrome of inappropriate ADH secretion

33

2 types of diabetes insipidus and definition in general

decreased ADH, leading to high urine output, dehydration, and high serum sodium (only losing H2O, not ions)

neurogenic

nephrogenic

34

neurogenic diabetes insipidus

caused by trauma, solve with ADH administration

decreased ADH, leading to high urine output, dehydration, and high serum sodium (only losing H2O, not ions)

35

nephrogenic diabetes insipidus

renal response off ADH decreased

decreased ADH, leading to high urine output, dehydration, and high serum sodium (only losing H2O, not ions)

36

what does ADH do cellularly

inserts aquaporins that are impermeable to ions

causes H2O to leave urine and enter the blood, causing low serum Na (diluted by the H2O)

decreases urine output

37

syndrome of inappropriate ADH secretion

causes dilutional hyponatremia

tumor can secrete extra ADH

treat with diuretics and fluid restriction

38

physiological effects of dilutional hyponatremia caused by syndrome of inappropriate ADH secretion

reabsorb H2O so low urine output

low serum sodium

high BP

39

isotonic fluid volume deficit

loss of isotonic fluid from ECF

ICF not impacted

40

causes, symptoms, and treatment of isotonic fluid volume deficit

causes: vomiting, diarrhea, NG suction

symptoms: thirst, weight loss, oliguria, increased urine specific gravity

treatment: correct problem and administer isotonic fluid

41

isotonic fluid volume excess

gain of isotonic fluid into ECF

ICF not impacted

42

causes, symptoms, and treatment of isotonic fluid volume excess

causes: renal or HF, corisol excess

symptoms: weight gain, edema, distended neck veins, pulmonary edema, ascites

treatment: sodium restriction and diuretics

43

hyponatremia

low serum Na of less than 135 mEq/L and low serum osmolarity

results from loss of Na in excess of (or without) H2O loss and gain of H2O without sodium

44

causes, symptoms, and treatment of hyponatremia

SIADH, renal disease that increases water retention

neuro (headache, disorientation), muscle cramps, weakness

limit H2O intake, give hypertonic sodium solutions if sever

45

water enters ICF by _____

osmosis

produces cellular edema (includes cerebral edema)

46

hypernatremia

serum Na less than 145 mEq/L and serum osmolarity > 295 mOsm/L

results from gain of sodium or loss of H2O

47

causes, symptoms, and treatment of hypernatremia

lack of H2O access, hypodypsia, excess sodium bicarb

weight loss, polycythemia, thirst, neuro symptoms

give rehydration fluids --> slowly to avoid cerebral edema

48

water leaves ICF by ____

osmosis

causes cellular dehydration

49

normal serum volume of potassium

3.5-4.5 mEq/L

50

regulation of potassium balance

renal regulation: K+ filtered and partially reabsorbed

excretion fine tuned by aldosterone-sensitive sodium reabsorption/potassium secretion in DCT

51

how are Na/K gradients maintained

Na/K ATPase pump

cellular dehydration --> increase K shift out of cells

intracellular acidosis --> increase K shift out of cells

Insulin and Epi stimulate pump --> increase K movement into cells

52

2 disorders of potassium imbalance

hyperkalemia

hypokalemiaq

53

hyperkalemia effect on resting membrane potential

reduces ratio so RMP is closer to threshold for AP

54

hypokalemia effect on resting membrane potential

increases ratio so RMP is further from threshold for AP

55

hyperkalemia

K+ > 5 mEq/L

causes: decreased renal elimination (CRF), increased movement from ECF (acidosis)

symptoms: peaked T wave, short QT, wide QRS!!!! weakness and muscle cramps

treat: CaCl2 to reverse ECG changes, beta-agonists, insulin

56

hypokalemia

K+ < 3.5 mEq/L

causes: decreased intake, vomiting, diarrhea, renal loss (diuretics), shifts into cells (epi & insulin), treatment of ketoacidosis

symptoms: PR prolonged, premature ventricular contractions, weakness, fatigue, muscle cramps

treat: replace with IV rapidly if needed

57

2 regulators of calcium

PTH increases calcium

calcitonin decreases calcium

58

PTH

increases calcium

increased absorption by gut (Vit D)

decreases renal elimination

stimulates osteoclasts (breakdown of bone)

59

calcitonin

decreases calcium

60

2 PTH disorders

hyperparathyroidism

hypoparathyroidism

61

hyperparathyroidism

excess PTH --> high calcium

parathyroid adenoma

skeletal abnormalities that may be asymtomatic

62

hypoparathyroidism

PTH deficit so low calcium

congenital absence of gland, acquired (surgery or radiation)

symptoms: tetany, prolonged QT

treat: IV calcium gluconate, Vit D

63

most calcium stored in ____

bone

64

calcium in ECF

1/2 calcium bound to albumin and 1/2 free

65

hypocalcemia

serum calcium less than 8.5 mg/dL

treat: replace calcium

66

causes and symptoms of hypocalcemia

causes: renal loss (failure) and hypoparathyroidism

symptoms: nerve and muscle excitability, tingling, spasms, and seizures b/c Ca stabilizes membranes

67

2 signs of hypocalcemia

Chvostek: contracture of facial muscles from light tap

Trousseau: carpal spasms from inflating BP cuff

68

hypercalcemia

serum calcium greater than 10.5 mg/dL

causes: bone resorption (cancer) and hyperparathyroidism

symptoms: decreased neural exitability

69

regulation of magnesium balance

reabsorption in DCT stimulated by PTH

70

hypomagnesemia

serum Mg less than 1.8 mg/dL

caused by diarrhea, malabsorption, laxatives

symptoms: tachycardia and HTN

71

hypermagnesemia

serum Mg greater than 2.6 mg/dL

caused by renal disease, and magnesium containing meds like antacids

symptoms: hypotension and cardiac arrest

72

why is pH important

enzymes are sensitive

cardiac and neural function is decreased when pH is low

73

acids are generated by ________

metabolism

74

fixed acids

sulfuric

phosphoric

lactic

ketone bodies

75

sulfuric and phosphoric acid

produced in metabolism of AA, NA, and phospholipids

excreted by kidney

76

lactic acid

from pyruvic acid in anaerobic metabolism

77

ketone bodies

from fat and protein during catabolism

78

volatile acid

CO2

end product of aerobic metabolism

H2O + CO2 --> H2CO3 --> H+ + HCO3-

79

high pCO2

acidosis

80

low pCO2

alkalosis

81

3 lines of defense against acidosis/alkalosis

1: chemical buffering

2: respiratory response by breathing out CO2

3: renal response

82

CO2 is produced in ____ and diffuses into ____

cells, plasma

83

CO2 in RBC and enzyme

H2O + CO2 --> H2CO3 --> H+ + HCO3-

by carbonic anhydrase

84

CO2 is carried in 3 forms

bicarb 70%

dissolved in plasma 10%

bound to hemoglobin 20%

85

calculation of pH

Henderson-Hasselbach

rate of bicarb to CO2 determines pH

pH = 6.1 + log [HCO3-] / (.03 * pCO2)

86

the log of a bigger # = a

bigger #

87

causes of acidosis bicarb/CO2

low biarb

high CO2

88

causes of alkalosis bicarb/CO2

high bicarb

low CO2

89

buffer systems

1st line of def

bicarbonate buffer system most important

H2O + CO2 --> H2CO3 --> H+ + HCO3-

if high pH, moves to right to release H+

if low pH, moves to left to absorb H+

90

protein buffer systems

albumin and globulins (major plasma proteins)

91

potassium H+ ion exchange

in metabolic acidosis H+ inc. in cells so K+ moved out

treatment of ketoacidosis requires K+ replacement

92

respiratory control of CO2

2nd line of def

increased production of metabolic acids or CO2 stimulates chemoreceptors

respiratory centers are stimulated to increase minute respiration (breathe more CO2 out to inc. pH)

rapid response... 12-24 hrs

93

acidosis means you breathe...

harder

94

alkalosis means you breathe

slower

95

renal control mechanisms

3rd line of def

kidney changes excretion of acid or base to compensate for pH changes

H+/bicarb exchange (requires carbonic anhydrase)

96

H+/bicarb exchange

H+ ions secreted into tubular fluid in exchange for Na

bicarb reabsorbed into blood

stimulated by acidosis

97

diamox

diuretic and carbonic anhydrase inhibitor

moves Na into urine and H2O follows

98

tubular buffer systems

prevent urine from becoming too acidic (excretes H+ ions)

phosphate buffer system

ammonia buffer system.... NH4+ produced and secreted and NH3 acts as buffer

99

lab tests for acid/base abnormalities

use arterial blood

pH and pCO2 measured, bicarb calculated

100

interpretation of lab acid/base tests

pH determines acidosis or alkalosis

if abnormal CO2, problem is respiratory

if abnormal HCO3-, problem is metabolic

101

_____ system can adjust CO2 to compensate for a _____ disorder

respiratory, metabolic

102

_____ system can adjust HCO3- to compensate for a _____ disorder

renal, respiratory

103

is mixed acidosis/alkalosis possible?

yes

104

anion gap

serum concentration of unmeasured anions (phosphate, sulfate, organic acids, protein)

calculated as sodium - (chloride + bicarb)

use to confirm diagnosis

105

anion gap is increased in...

lactic acidosis

ketoacidosis

b/c large amounts of lactate and ketone present (anions)

106

anion gap is normal from ______

diarrhea

Cl retained as bicarb is lost

107

anion gap is decreased in...

hypoalbuminemia