fluid and electrolytes Flashcards
1
Q
a delicate balance of fluids, electrolytes, and acids and bases maintained in the body
A
HOMEOSTASIS
2
Q
approximately 60% of average healthy adult’s weight (70% to 80% in infants and 50% to people older than 50)
A
Water
3
Q
Water is the primary
A
body fluid
3
Q
TWO COMPARTMENTS OF BODY’S FLUID
A
INTRACELLULAR FLUID (ICF)
EXTRACELLULAR FLUID (ECF)
4
Q
found within the cells of the body; 2/3 of the total body fluid in adults
A
INTRACELLULAR FLUID (ICF)
5
Q
found outside the cells; 1/3 of the total body fluid
A
EXTRACELLULAR FLUID (ECF)
6
Q
20% of the ECF; found within the vascular system
A
INTRAVASCULAR FLUID (PLASMA)
7
Q
75% of the ECF; surrounds the cells
A
INTERSTITIAL FLUID
8
Q
charged particles
A
ions
9
Q
ions that carry a positive charge
A
cations
10
Q
ions that carry a negative charge
A
anions
11
Q
minerals in the body that have electrical charge; chemicals from which ions are made
A
Electrolytes
12
Q
are generally measured in milliequivalents per Liter of water (mEq/L) or milligrams per 100 milliliters (mg/100mL)
A
electrolytes
13
Q
Sodium (Na+)
Potassium (K+)
Calcium (Ca++)
Magnesium (Mg++)
A
cations
14
Q
Chloride (Cl-)
Bicarbonate (HCO3-)
Phosphate (HPO4–)
Sulfate (SO4–)
A
anions
15
Q
selectively permeable/semi-permeable to solutes
A
membranes
16
Q
MOVEMENT OF BODY FLUIDS AND ELECTROLYTES
A
Osmosis
Diffusion
Filtration
Active Transport
17
Q
Movement of water across cell membranes, from the less concentrated solution to the more concentrated solution
A
osmosis
18
Q
substances
dissolved in a liquid
A
solute
19
Q
component that
can dissolve a solute
A
solvent
20
Q
the concentration of solutes in body fluids; solute per kilogram of water
A
OSMOLALITY
21
Q
power of a solution to draw water across a semipermeable membrane
A
OSMOTIC PRESSURE
22
Q
pulls water from the interstitial space into the vascular compartment
A
COLLOID OSMOTIC PRESSURE (ONCOTIC PRESSURE)
23
Q
solute and solvent are equal
A
Isotonic solution
24
higher osmolality than body fluids; cells shrink
Hypertonic solution
25
lower osmolality than body fluids; cells swell
Hypotonic solution
26
Movement of molecules through a semipermeable membrane from an area of higher concentration to an area of lower concentration
diffusion
27
Fluid and solutes move together across a membranes from an area of higher pressure to one of lower pressure.
filtration
28
pressure in the compartment that results in the movement.
Filtration pressure
29
pressure
exerted by a fluid within a
closed system on the walls
of the container in which it is
contained.
Hydrostatic pressure
30
Substances can move across cell membranes from a less concentrated solution to a more concentrated one
ACTIVE TRANSPORT
31
It differs from diffusion and osmosis
in that metabolic energy is expended
ACTIVE TRANSPORT
32
A substance combines with a carrier on the outside surface of the cell membrane.
ACTIVE TRANSPORT
33
Fluid Intake
Fluid Output
Maintaining Homeostasis
REGULATING BODY FLUIDS
34
An average adult needs 2,500 mL per day.
fluid intake
34
amount in oral fluids
1,200 to 1,500 mL
35
amount in Water in foods
1,000 mL
35
amount Water as by-product of food metabolism
200 mL
36
total amount intake
2,400 to 2,700 mL
37
it takes 30 minutes to 1 hour for the fluid to be absorbed and distributed throughout the body
Thirst mechanism
37
primary regulator of fluid intake
- thirst center is located in the hypothalamus of the brain.
Thirst mechanism
37
Fluid losses that counterbalance the adult’s 2,500-mL average fluid intake.
fluid output
38
amount in urine
1,400 to 1,500 mL
39
amount in Insensible Losses
Lungs (water vapor in the expired air)
Skin
350 mL to 400 mL
39
amount in Sweat
100 mL
40
amount in Feces
100 mL to 200 mL
41
total amount output
2,300-2,600 mL
42
Homeostatic regulators/mechanisms:
1. Kidneys
2. Antidiuretic Hormone
3. Renin-Angiotensin-Aldosterone System
4. Atrial Natriuretic Factor
43
Primary regulator of body fluids and electrolyte balance.
kidneys
44
Regulates water and electrolyte secretion
kidneys
44
Plays a significant role in acid-base regulation, excreting hydrogen ion (H+) and retaining bicarbonate.
kidneys
45
Regulates water excretion from the kidney
Antidiuretic Hormone (ADH)
46
Produced when serum osmolality rises; conversely, ADH is suppressed when serum osmolality decreases
Antidiuretic Hormone (ADH)
47
Synthesized in the anterior portion of the hypothalamus
Antidiuretic Hormone (ADH)
48
Restore blood volume (and renal perfusion) through sodium and water retention
Renin-Angiotensin-Aldosterone System
49
1. When blood flow or pressure to kidneys decreases, renin is released.
2. Renin causes the conversion of angiotensin to angiotensin I, which is converted to angiotensin II by angiotensin-converting enzyme.
3.Angiotensin II acts directly on the nephrons to promote Sodium and water retention.
4.Stimulates the release of Aldosterone from the adrenal cortex. It promotes sodium retention.
Renin-Angiotensin-Aldosterone System
50
Released from cells in the atrium of the heart in response to excess blood volume and stretching the atrial walls.
Atrial Natriuretic Factor (ANF)
51
Promotes sodium wasting and acts as a potent diuretic, thus reducing vascular volume.
Atrial Natriuretic Factor (ANF)
51
Reduces thirst, reducing fluid intake
Atrial Natriuretic Factor (ANF)
52
Importance of electrolytes:
Maintaining fluid balance
Contributing to acid-base regulation
Facilitating enzyme reactions
Transmitting neuromuscular reactions
53
Electrolytes
Sodium (Na+)
Potassium (K+)
Calcium (Ca++)
Magnesium (Mg++)
Chloride (Cl-)
Phosphate (PO4-)
Bicarbonate (HCO3-)
54
Most abundant cation in the ECF and a major contribution to serum osmolality.
Sodium (Na+)
55
Normal value: 135-145 mEq/L
Sodium (Na+)
56
Aids in transmitting nerve impulses and contracting muscles
Sodium (Na+)
57
Major cation in ICF, with only small amount found in ECF.
Potassium (K+)
58
Normal serum levels: 3.5 to 5.0 mEq/L
Potassium (K+)
59
Vital electrolyte for skeletal, cardiac, and smooth muscle activity.
Potassium (K+)
60
Must be consumed everyday because the body cannot conserve it.
Potassium (K+)
61
Sources: avocado, raw carrot, spinach, dried fruits, banana, apricot, orange, beef, pork, milk
Potassium (K+)
62
found in the skeletal system, with a relatively small amount in the ECF.
Calcium (Ca++)
63
Vital in regulating muscle contraction and relaxation, neuromuscular function, and cardiac function
Calcium (Ca++)
64
Normal total serum levels: 8.5-10.5 mg/dL
Calcium (Ca++)
65
Normal ionized serum levels: 4-5 mg/dL
Calcium (Ca++)
66
decreases serum levels
calcitonin
66
Parathyroid hormone and calcitriol increase serum
Calcium (Ca++)
67
Daily intake should be 1,000-1,500 mg
Calcium (Ca++)
68
Primarily found in the skeleton and in ICF
Magnesium (Mg++)
69
Second most abundant ICF cation
Magnesium (Mg++)
69
Sources: cereal grains, nuts, dried fruits, legumes, green, leafy vegetables, dairy products, meat, fish
Magnesium (Mg++)
70
Normal serum levels: 1.5 to 2.5 mEq/L
Magnesium (Mg++)
71
Aids in relaxing muscle contractions, transmitting nerve impulses, regulating cardiac function, and intracellular metabolism.
Magnesium (Mg++)
72
Major anion of the ECF
Chloride (Cl-)
73
Normal serum levels: 95 to 108 mg/dL
Chloride (Cl-)
74
When sodium is reabsorbed in the kidney, chloride usually follows.
Chloride (Cl-)
75
Major component of gastric juice (HCl), and is involved in regulating acid-base balance.
Chloride (Cl-)
76
Found in the same foods as Sodium
Chloride (Cl-)
77
Major anion of ICF
Phosphate (PO4-)
77
Also found in the ECF, bone, skeletal muscle, and nerve tissue
Phosphate (PO4-)
78
Normal serum levels: 2.5 to 4.5 mg/dL
Phosphate (PO4-)
79
Aids in metabolizing Carbohydrate, Protein, and Fat; it is absorbed in the intestines
Phosphate (PO4-)
80
Sources: meat, fish, poultry, milk products, legumes
Phosphate (PO4-)
81
Present in both ICF and ECF
Bicarbonate (HCO3-)
82
Primary function is to regulate acid-base balance (major body buffer)
Bicarbonate (HCO3-)
83
Regenerated by the kidneys
Bicarbonate (HCO3-)
84
ECF bicarbonate levels are regulated by the kidney
Bicarbonate (HCO3-)
85
Produced through metabolic processes
Bicarbonate (HCO3-)
86
substance that releases hydrogen ions (H+)
acid
87
have a low hydrogen ion
concentration and can accept hydrogen ions in
solution.
Bases (Alkalis)
87
the relative acidity or alkalinity of a solution
- reflects the hydrogen ion concentration of the solution (inversely proportional)
PH
88
normal pH:
7.35-7.45
89
REGULATION OF ACID-BASE BALANCE
Buffers
Respiratory Regulation
Renal Regulation
89
prevent excessive changes in pH by removing or releasing hydrogen ions.
BUFFERS
90
Major buffer systems in the ECF:
Bicarbonate (HCO3-)
Carbonic acid (H2CO3)
91
weak acid
Carbonic acid (H2CO3)
92
acid buffer; opponent of acids
Bicarbonate (HCO3-)
93
TO ACHIEVE NORMAL pH
1 part Carbonic Acid (1.2 mEq/L) : 20 parts bicarbonate (24 mEq/L)
94
adding a strong acid in the ECF, depleting the bicarbonate and lowering the pH levels.
acidosis
95
adding a strong base to the ECF, depleting carbonic acid as it combines with the base, increasing the pH levels.
alkalosis
96
The lungs help regulate acid-base balance by eliminating or retaining Carbon Dioxide (CO2), a potential acid.
RESPIRATORY REGULATION
97
Carbon Dioxide (CO2) + Water (H2O) =
Carbonic acid (H2CO3)
98
High Carbonic acid (H2CO3) and CO2 levels =
respiration rate and depth increases, exhaling CO2 and decreasing carbonic acid levels
99
High Bicarbonate (HCO3-) levels =
the respiration rate and dept are reduced, retaining CO2 and increasing carbonic acid levels
100
are the ultimate long-term regulator of acid-base balance, although slower to respond to changes.
Kidneys
101
regulate pH by reabsorbing and regenerating bicarbonate and hydrogen ions
kidneys
102
Carbonic acid (H2CO3) =
Hydrogen ion (H+) + Bicarbonate (HCO3-)
103
kidneys reabsorb and regenerate bicarbonate and excrete hydrogen ions
H2CO3 >> H+ (excreted) and HCO3- (retained)
High H+ ions (acidic)
104
FACTORS AFFECTING BODY FLUID, ELECTROLYTES, AND ACID-BASE BALANCE:
Age
Gender and Body Size
Environmental Temperature
Lifestyle
105
two types of Fluid Imbalances
isotonic
osmolar
106
excess bicarbonate is excreted and H+ ion is retained
H2CO3 >> H+ (retained) and HCO3- (excreted)
Low H+ ions (alkalosis)
107
water and electrolytes are lost or gained in equal proportions
isotonic
108
loss or gain of only water, so that the osmolality of the serum is altered (electrolytes are concentrated)
osmolar
108
Four Categories of Fluid Imbalances
Fluid Volume Deficit
Fluid Volume Excess
Dehydration (hyperosmolar imbalance)
Overhydration (hypo-osmolar imbalance)
109
The body loses both water and electrolytes from the ECF (intravascular compartment) in similar proportions, so it often is called
hypovolemia
110
Causes of hypovolemia
Abnormal losses through the skin, GI tract, kidney
Movement of fluid in a third space (area that deems the fluid unavailable for us)
111
The body retains both water and sodium in similar proportions to normal ECF, often called
hypervolemia
112
Increased intake of NaCl (sodium level is still normal, since both water and sodium are equally retained)
Infusion of sodium-containing fluids rapidly
Disease processes (heart failure, kidney failure, liver cirrhosis)
causes of hypervolemia
113
excess interstitial fluid
edema
114
leaves a small depression or pit after finger pressure is applied
pitting edema
115
Water is lost from the body, leaving the client with excess sodium
Sodium levels are increased
Cells are dehydrated/shrunk
Dehydration (Hyperosmolar imbalance)
116
causes of Dehydration (Hyperosmolar imbalance)
Diabetic Ketoacidosis (DKA)
Osmotic diuresis
Administration of hypertonic solutions
116
Water is gained in excess of electrolytes, resulting in low serum osmolality and low serum Na+ levels
Cells are swollen
Can lead to cerebral edema and impaired neurologic function
Overhydration (hypo-osmolar imbalance)
117
causes of Overhydration (hypo-osmolar imbalance)
Syndrome of Inappropriate Anti-Diuretic Hormone (SIADH)
Head Injury
118
Less than 135 mEq/L
Severe cases: <110 mEq/L
Can lead to neurological damage (cerebral edema) due to low serum osmolality
Causes: burns, GI losses, diuretics, head injury
Hyponatremia
119
Higher than 145 mEq/L
Cells are dehydrated
Primary manifestations are neurological in nature
Causes: water deprivation, diabetes insipidus, excessive use of NaCl
Hypernatremia
120
Less than 3.5 mEq/L
Causes:
GI losses (vomiting, diarrhea)
Potassium-wasting diuretics
Poor intake of Potassium
- S/Sx: muscle weakness, lethargy, cardiac dysrhythmias
Hypokalemia
121
More than 4.5 mEq/L
More dangerous than hypokalemia – can lead to cardiac arrest
Causes:
1. Renal Failure
2. High Potassium Intake
3. Burns
- S/Sx: confusion, muscle weakness, bradycardia, irregular pulse, numbness in extremities
hyperkalemia
122
Total calcium: <8.5 mg/dL
Ionized calcium: <4 mg/dL
SEVERE HYPOCALCEMIA CAN CAUSE TETANY WITH MUSCLE SPASMS AND PARESTHESIAS AND CAN LEAD TO CONVULSIONS. Other manifestations include: decreased cardiac output, hyperactive DTR
Two signs:
Chvostek’s sign
Trousseau’s sign
Causes: total thyroidectomy, hypomagnesemia, chronic alcoholism
hypocalcemia
123
Total calcium: >10.5 mg/dL
Ionized calcium: >5 mg/dL
Calcium is mobilized from the skeleton due to malignancy or prolonged immobilization
S/Sx: depressed DTR, cardiac dysrhythmias, hypercalciuria, flank pain secondary to urinary calculi
hypercalcemia
124
when a carpopedal spasm of the hand and wrist occurs after an individual wears a blood pressure cuff inflated over their systolic blood pressure for 2 to 3 minutes
Trousseau’s sign
124
increased irritability of the facial nerve, manifested by twitching of the ipsilateral facial muscles on percussion over the branches of the facial nerve,
Chvostek’s sign
124
Less than 1.5 mEq/L
Common cause: chronic alcoholism
Other causes: GI losses, burns, pancreatitis
S/Sx: Chvostek’s and Trousseau, increased reflexes, respiratory difficulties, cardiac dysrhythmias
hypomagnesemia
125
More than 2.5 mEq/L
Often iatrogenic (result of overzealous magnesium therapy)
S/Sx: depressed DTR, bradycardia, lethargy, respiratory depression, cardiac arres
hypermagnesemia
126
Below 95 mEq/L
Causes: GI/kidney losses, sweating
S/Sx: muscle twitching, tremors, tetany
Hypochloremia
127
Above 108 mEq/L
Causes: excess replacement of NaCl or KCl
S/Sx: acidosis, weakness, lethargy, dysrhythmias, coma
Hyperchloremia
128
Below 2.5 mg/dL
Causes: GI losses, use of phosphate-binding antacids, alcohol withdrawal
S/Sx: paresthesias, muscle weakness and pain, metal changes, and possible seizures
Hypophosphatemia
129
Above 4.5 mg/dL
Causes: tissue trauma, chemotherapy, renal failure, increased ingestion/administration of phosphate
- S/Sx: numbness, tingling around the mouth and fingertips, muscle spasms, tetany
Hyperphosphatemia
130
Acid-base imbalances classified as
respiratory or metabolic
131
normally regulated by the lungs through the retention/excretion of CO2 (respiratory acidosis or alkalosis)
carbonic acid levels
132
are regulated by the kidneys (metabolic acidosis or alkalosis)
Bicarbonate and Hydrogen ion levels
133
134
