Fluids and Electrolytes Flashcards
(121 cards)
1
Q
What do the body fluids consist of?
A
Water and dissolved solutes
2
Q
What are electrolytes?
A
Solutes that dissolved in body fluids and dissociate into ions
3
Q
How much of the human body mass does water account for?
A
45%-75%
4
Q
Describe distribution of body fluids in the average lean female
A
55% fluids but 45% solids
5
Q
Describe the distribution of body fluids of the average, lean male
A
40% solids
60% fluids
6
Q
Describe the chemical composition of total body fluid
A
2/3 intracellular fluids
1/3 extracellular fluids
7
Q
Describe the chemical composition of extracellular fluid
A
80% interstitial fluid
20% plasma
8
Q
What is fluid balance?
A
Water and solutes are in equivalent proportion in various body compartments
9
Q
____________ is the primary way in which water moves in and out of body compartments
A
Osmosis
10
Q
The concentration of ___________ mandates the direction of water movement and hence …
A
Solutes
…are the major determinants of fluid balance
11
Q
What is osmolarity?
A
The measure of solute concentration defined as number of moles per liter of solution
12
Q
What are the units of osmolarity?
A
Osmol/L
Or
Osm/L
13
Q
ICF and ECF normally have equal osmolarity so cells…
A
…neither shrink nor swell
14
Q
_____________ occurs if the osmolarity changes
A
Imbalance
15
Q
What happens due to an increase in osmolarity in interstitial fluid?
A
Will draw water out of the cell and cause the cell to shrink
16
Q
What happens when there is a decrease in osmolarity in the interstitium(ECF)?
A
Water will draw out of the cell and cause it to swell and can lead to water intoxication
17
Q
In the CNS, water intoxication/decrease in osmolarity in ECF causes
A
Convulsions
Coma
Death
18
Q
Convulsions, coma and death may result from water intoxication/decreased osmolarity in ECF unless…
A
… oral rehydration includes small amount of salt in water intake
19
Q
_____________ secretion shuts off after intake of water
A
ADH
20
Q
ADH secretion is increased if there is:
A
- Large decrease in blood volume
- Severe dehydration and drop in blood pressure
- Vomiting, diarrhea, heavy sweating or burns
21
Q
ADH does what in terms of fluid balance?
A
Stimulates thirst
Increases permeability of principle cells in collecting ducts to assist in water reabsorption
-Very concentrated urine is formed
22
Q
What is dehydration?
A
The loss of body fluids
23
Q
Describe the process of thirst stimulation to increase water intake
A
Dehydration
- > decreased saliva flow, increased blood osmolarity and decreased blood volume
- > dry mouth and pharynx due to decreased saliva flow
- > increased blood osmolarity leads to stimulation of osmolarity in the hypothalamus
- > decreased blood volume leads to decreased pressure, this causes renin to be secreted by juxtamedullary cells in kidney to produce angiotensin 2
-> angiotensin 2, dry mouth and pharynx and stimulation of osmoreceptors in hypothalamus stimulate thirst center in hypothalamus and increases thirst
24
Q
What is hyponatremia?
A
Decreased Na+ concentration of interstitial fluid and plasma
25
What hormones increase Na+ and Cl- reabsorption
Aldosterone and Angiotensinogen 2
26
What hormone increases Na+ and Cl- excretion?
Atrial naturiuretic peptide
27
What are the 4 general functions of electrolytes?
Control the osmosis of water between body compartments
Maintain acid base balance
Carry electrical current which allows for production of action potentials and graded potentials
Serve as cofactors needed for optimal activity of enzymes
28
Explain the series of events which can lead to coma, convulsions and possible death?
1. Blood loss, sweating, vomiting or diarrhea coupled with intake of plain water
2. Decreased Na+ concentration of interstitial and plasma(hyponatremia)
3. Decreased osmolarity of interstitial fluid and plasma
4. Osmosis of water from interstitial fluid into intracellular fluid
5. Water intoxication(cells swell)
6. Convulsions, coma and possible death
29
Explain hormonal regulation of Na and Cl reabsorption
1. Increased intake of NaCl
2. Increased plasma concentrations of Na+ and Cl-
3. Increased osmosis of water from intracellular fluid to interstitial fluid to plasma
4. This leads to increased blood volume
5. In the heart: increased atrial stretching leads to release of atrial natriuretic peptide
6. Decreased renin, angiotensin 2 and aldosterone from increased blood pressure leads to increased glomerular filtration rate
7. Atrial natriuretic peptide, decreased aldosterone and increased glomerular filtration rate leads to reduced NaCl reabsorption in the kidneys
8. Increased loss of Na+ and Cl- in urine leads to increased water loss and decreased blood volume
30
How is the charge carried by ions in different solutions compared?(units)
Milliequivalents/liter (mEq/ liter)
31
What is expressed in milliequivalents/liter (mEq/Liter)?
- Cations(positively charge)
| - Anions (negatively charged) in a solution
32
What electrolytes does the extracellular fluid contain?
Na+ and Cl-
33
What does intracellular fluid contain?
K+ and phosphates
34
Contrast plasma and interstitial fluid in terms of contents
Plasma contains many proteins but interstitial fluid doesn’t
Interstitial fluid- Na+ and Cl-
35
What is the most abundant ion in the ECF?
Sodium, Na+
36
_________ accounts for half of the serum osmarility
Sodium
37
This electrolyte is the mist abundant in ECF and necessary for action potentials across cellular membranes
Sodium Na
38
What 3 hormones regulate Sodium and how?
Aldosterone increases sodium absorption
ADH secretion increases if Na+ level are less than 135 mEq
ANP excretes Na+ and water
39
What is the most prevalent anion in the ECF?
Chloride, Cl-
40
Why do chloride ions move easily between compartments?
Due to Cl leakage channels
41
Chloride anions help balance _________ in different compartments
Anions
42
Explain the regulation of Chloride
- Follows Na+ passively so it is indirectly regulated by aldosterone
- ADH helps regulate Cl in body fluids because it controls water loss in urine
43
How does chloride shift across red blood cells?
With buffer movement
44
What is the most abundant cation in the intracellular fluid?
Potassium cation
45
What is the function of potassium in the nervous system?
Helps establish resting potential and repolarization of membrane in nerve and muscle fibers
46
What is the function for K+ for pH regulation in the body?
K+ exchanged for H+
47
Explain the relationship between K+ and aldosterone
High levels of K+ stimulates secretion of aldosterone which increases K+ excretion in the kidneys
48
Abnormal plasma K+ levels adversely effect ________ and ______________________ function
Cardiac
Neuromuscular
49
What causes blood increase and decrease of bicarbonate? HCO3-
Major component of the plasma acid-base buffer system
- Concentration increases as blood flows through systemic capillariesbdue to carbon dioxide is released from cell metabolism
- concentration decreases as blood flows through pulmonary capillaries and carbon dioxide is exhaled
Intercalated cells excrete more if levels are low
Excess is excreted in urine
50
What are the main regulators of plasma levels?
Kidneys
51
What are the functions of calcium?
Structural component of bones and teeth
Important to blood clotting, neurotransmitter release, muscle tone and function and nerve function
52
What regulates calcium levels?
Parathyroid hormone (PTH)
Stimulates osteoclasts to release calcium from bone
Increases production of calcitrol(Ca2+ absorption from GI tract and reabsorption from glomerular filtration rate
53
What is the second most common intracellular cation?
Magnesium
54
How much of magnesium is found in bone matrix?
54%
55
What are the functions of magnesium?
- activates several enzyme systems involved in carb and protein metabolism
- needed for operation of sodium pump
- neuromuscular activity
- neural transmission within the central nervous system
Myocardial functioning
56
_________ accounts for half of the serum osmarility
Sodium
57
This electrolyte is the mist abundant in ECF and necessary for action potentials across cellular membranes
Sodium Na
58
What 3 hormones regulate Sodium and how?
Aldosterone increases sodium absorption
ADH secretion increases if Na+ level are less than 135 mEq
ANP excretes Na+ and water
59
What is the most prevalent anion in the ECF?
Chloride, Cl-
60
Why do chloride ions move easily between compartments?
Due to Cl leakage channels
61
Chloride anions help balance _________ in different compartments
Anions
62
Explain the regulation of Chloride
- Follows Na+ passively so it is indirectly regulated by aldosterone
- ADH helps regulate Cl in body fluids because it controls water loss in urine
63
How does chloride shift across red blood cells?
With buffer movement
64
What is the most abundant cation in the intracellular fluid?
Potassium cation
65
What is the function of potassium in the nervous system?
Helps establish resting potential and repolarization of membrane in nerve and muscle fibers
66
What is the function for K+ for pH regulation in the body?
K+ exchanged for H+
67
Explain the relationship between K+ and aldosterone
High levels of K+ stimulates secretion of aldosterone which increases K+ excretion in the kidneys
68
Abnormal plasma K+ levels adversely effect ________ and ______________________ function
Cardiac
Neuromuscular
69
What causes blood increase and decrease of bicarbonate? HCO3-
Major component of the plasma acid-base buffer system
- Concentration increases as blood flows through systemic capillariesbdue to carbon dioxide is released from cell metabolism
- concentration decreases as blood flows through pulmonary capillaries and carbon dioxide is exhaled
Intercalated cells excrete more if levels are low
Excess is excreted in urine
70
What are the main regulators of plasma levels?
Kidneys
71
What are the functions of calcium?
Structural component of bones and teeth
Important to blood clotting, neurotransmitter release, muscle tone and function and nerve function
72
What regulates calcium levels?
Parathyroid hormone (PTH)
Stimulates osteoclasts to release calcium from bone
Increases production of calcitrol(Ca2+ absorption from GI tract and reabsorption from glomerular filtration rate
73
What is the second most common intracellular cation?
Magnesium
74
How much of magnesium is found in bone matrix?
54%
75
What are the functions of magnesium?
- activates several enzyme systems involved in carbohydrate and protein metabolism
- needed for operation of sodium pump
- neuromuscular activity
- neural transmission within the central nervous system
Myocardial functioning
76
What factors regulate magnesium ion concentration in plasma?
Hypo- or hyperglycemia
Hypo or hypermagnesemia
Increase or decrease in extra cellular fluid volume
An increase or decrease in the parathyroid hormone
Acidosis or alkalosis
77
In what form is phosphate present in bones and teeth?
Calcium phosphate?
78
What regulates phosphate levels in the plasma?
Parathyroid hormone and calcitriol
79
How do parathyroid hormone and calcitriol regulate phosphate plasma levels?
Reabsorption of bone releases phosphate
In the kidney, PTH increase phosphate excretion
Calcitriol increases GI absorption of phosphate
80
People at risk for electrolyte Imbalance include:
Dependents in others for fluid and food needs
Undergoing medical treatment using intravenous infusions, drainage or suction and urinary catheters
Receiving diuretics
Post-operative individuals
Burn victims
Patients with chronic disease and with altered states of consciousness
81
High protein diets tend to ___________ the blood
Acidify
82
The overall acid-base balance is maintained by controlling the _______________ of body fluids, especially ECF
Proton concentration
83
What are the 3 major mechanisms to regulate pH in body fluids?
1. Buffer systems
2. Exhalation of Carbon Dioxide(respiratory system)
3. Kidney excretion of protons (urinary system)
84
Why is HPO4- an important buffer?
Acts as a buffer of protons in body fluids and urine.
Mono and dihydrogenphosphate act as buffers in the blood
85
What are the functions of buffer systems?
Prevent rapid, drastic changes in pH
Change either strong acid or base into a weaker one
Work in fractions of a second
86
What are the 3 principle buffer systems?
- protein buffer system
- carbonic acid-bicarbonate buffer system
- phosphate buffer system
87
Explain the protein buffer system
Some side chains buffer protons
-Amino acids have at least one carboxyl group (COOH) and releases a protein when pH is high(in alkaline solution)
-Amino acids also contain an amino group
Which acts as a base and accepts a protein when is in an acidic solution/ or pH is low
88
Explain the carbonic acid buffer system(use equations)
Carbonic acts as an extracellular and intracellular buffer system
- bicarbonate acts as a weak base if there is too much acid= H+ and HCO3- -> H2CO3 -> CO2 + H2O
carbonic acid(H2CO3) can act as a weak acid if there is too little
H2CO3 -> H+ and HCO3-
89
The phosphate buffer system is most important _______________ but also acts to buffer acids in _______________
Intracellularly
Urine
90
Explain the phosphate buffer system(using equations)
Dihydrogen phosphate acts as a weak acid that can buffer a strong base
OH- + H2PO4 -> H2O + H2PO4 ^2-
Mono hydrogen phosphate acts as a weak base by buffering the H+ released by a strong acid
H+ and HPO4 ^2- -> H2PO4 ^-
91
Explain regulation of pH by exhaling Carbon Dioxide
- Increasing breathing rate increases blood pH
- Slow breathing rage causes pH to drop
- Kidneys excrete H+ and absorb HCO3^- to aid in maintaining pH(slower)
- H+ detected by chemoreceptors in medulla oblangata, carotid and aortic bodies
- Respiratory centers inhibited or stimulated by changes is pH
92
Go back to chart
Go back to chart
93
Kidneys eliminate excess __________ or _______
Acids
Bases
94
Why can renal failure cause death very rapidly?
Due to its role in pH balance
95
How much nonvolatile acid is produced by metabolic reactions?
1 mEq/liter of nonvolatile acid for every kilogram of body weight
96
What are the 2 types of cells that make up the intercalated cells in the kidney
Beta cells
Alpha cells
97
What is the responsibility of the alpha cells in intercalated cells?
Secrete excess protons and reabsorb bicarbonate ions
98
What is the responsibility of beta cells in the intercalated cells?
To secrete bicarbonate ions and reabsorb protons
99
What cells are responsible for acid-base homeostasis that are in the kidneys?
Alpha cells and beta cells
100
Ammonia and mono hydrogen phosphate are _______ _________
Urinary buffers
101
How do ammonia and mono hydrogen phosphate act as urinary buffers?
They both accept protons
Ammonia becomes ammonium
Monohydrogen phosphate becomes adihydrogen phosphate
102
What is acidosis?
Blood pH below 7.35
103
What is alkalosis?
pH above 7.45
104
What is the principle effect of. Acidosis?
The depression of the central nervous system through depression of synaptic transmission
105
What is the principle effect of alkalosis?
The principle effect is the over-excitability of the central nervous system through facilitation of synaptic transmission
106
What is compensation?
An attempt to correct an acid base imbalance
107
What are the 2 types of compensation?
Renal compensation
Respiratory compensation
108
Acidosis causes...
Depression of CNS and coma
109
Alkalosis causes …
Excitability of nervous tissue leading to spasms convulsions and death
110
How is acid base balance diagnosed/ evaluated?
Systemic arteriole blood pressure
Concentration of bicarbonate( too low or too high)
Partial pressure of carbon dioxide( Too low or too high)
111
What are respiratory acidosis and alkalosis?
Disorders involving changes in partial pressure if carbon dioxide in blood. Supposed to be (35- 45mEq/L)
112
What are metabolic acidosis and alkalosis?
Disorders due to changes bicarbonate ion concentration in blood. Supposed to be 22-36 mEq/L
113
Why do infants produce more metabolic wastes?
Higher metabolic rate
114
In infants kidneys cannot __________ _______ nor remove excess _________
Concentrate urine
Protons/H+
115
Why do infants lose more water through skin?
Because surface area to volume ratio is greater
116
Why do infants have a higher breathing rate?
Due to increased water loss from lungs
117
Compare ion concentration in infants to adults
Higher K+ and Cl- concentrations than adults
118
Compare the amount of body water in ECF of infants to adults
Infants have more body water in ECF
119
Compare fluid intake between infants and adults
Rate of fluid intake/output is 7 times higher than adults
120
Compare K+ concentration in elderly to younger adults
Decreased total body K+ due to loss of muscle tissue or potassium depleting diuretics for treatments of hypertension or heart disease
121
Why do the elderly experience decreased renal function and respiratory function?
- Slowing of exhalation of CO2
- decreased blood flow and glomerular filtration rate
- reduced sensitivity to ADH and impaired ability to produce dilute urine
- Renal tubule cells produce less ammonia to combine with H+ and excrete as NH4^+
