Electrolyte /Acid Base Flashcards
1
Q
What percentage of the human body is composed of water?
A
66%
2
Q
What are the two main fluid compartments in the body?
A
Intracellular fluid (ICF) and Extracellular fluid (ECF)
3
Q
What condition results from excessive accumulation of fluid in the interstitial compartment?
A
Edema
4
Q
What role does the hypothalamus play in regulating water balance?
A
The hypothalamus senses intracellular differences and adjusts the release of AVP (antidiuretic hormone) to regulate water balance.
5
Q
What happens when the hypothalamus does not sense any intracellular drift in osmolality?
A
When the hypothalamus does not sense any intracellular drift in osmolality, it does not release AVP or reduces its production, leading to an increase in urine flow.
6
Q
How does AVP (antidiuretic hormone) influence water balance in the body?
A
AVP influences water balance by regulating the reabsorption of water in the kidneys, which affects urine concentration and volume.
7
Q
What is the relationship between osmolality and the release of AVP?
A
The release of AVP is regulated by changes in osmolality.
When osmolality increases, AVP is released to promote water reabsorption, and when osmolality is stable, AVP release is reduced.
8
Q
What is the average daily water intake and output for an adult?
A
2500 mL
9
Q
Which is the predominant extracellular cation and anion?
A
Cation: Sodium (Na+), Anion: Chloride (Cl-)
10
Q
Which is the predominant intracellular cation and anion?
A
Cation: Potassium (K+), Anion: Phosphates
11
Q
What hormone regulates sodium and potassium levels in the kidney tubules?
A
Aldosterone
12
Q
How does sodium concentration affect water movement between compartments? after graph
A
High sodium concentration draws water from intracellular to extracellular space due to osmotic pressure.
13
Q
What is the major cation in blood plasma and interstitial fluid?
A
Sodium (Na+)
14
Q
What are the major anions in blood plasma and interstitial fluid?
A
Chloride (Cl-) and Bicarbonate (HCO3-)
15
Q
What is the predominant cation in intracellular fluid (cell fluid)?
A
Potassium (K+)
16
Q
What is the major anion in intracellular fluid (cell fluid)?
A
Phosphate (HPO4^2-)
17
Q
What are examples of minor cations in body fluids?
A
Calcium (Ca^2+) and Magnesium (Mg^2+)
18
Q
What are “nonelectrolytes” in the context of this image?
A
Substances that do not dissociate into ions in solution (e.g., glucose, lipids, creatinine
19
Q
What does “meq/liter” stand for?
A
Milliequivalents per liter, a measure of the amount of electrolytes in a solution.
20
Q
What does the graph illustrate?
A
The electrolyte composition of body fluids (blood plasma, interstitial fluid, and intracellular fluid).
21
Q
Where is protein concentration highest?
A
Intracellular fluid (cell fluid).
22
Q
What is the significance of understanding electrolyte distribution in the body?
A
Electrolytes play crucial roles in maintaining fluid balance, nerve function, muscle contraction, and other essential physiological processes.
23
Q
What are the two main categories of causes for water depletion?
A
Inadequate intake and abnormal losses via lungs, skin, or renal tract.
24
Q
Give an example of inadequate water intake leading to depletion.
A
Infants, patients in coma, or those with nausea or dysphagia.
25
Give an example of abnormal water loss via the lungs.
Inadequate humidification in mechanical ventilation.
26
Give an example of abnormal water loss via the skin.
Fevers and hot climates.
27
Give an example of abnormal water loss via the renal tract.
Diabetes insipidus or lithium therapy.
28
What are the two main categories of causes for excess water?
Excessive intake and renal retention.
29
Give an example of excessive water intake (oral).
Psychogenic polydipsia.
30
Give an example of excessive water intake (parenteral).
Hypotonic infusions after operations.
31
Give an example of renal retention of water.
Excess vasopressin (SIADH), low adrenal functioning, hypothyroidism.
32
What are the main categories of causes for sodium depletion?
Inadequate oral intake and abnormal losses via skin, GI tract, or renal tract.
33
Give an example of abnormal sodium loss via the skin.
Excessive sweating, dermatitis, burns.
34
Give an example of abnormal sodium loss via the GI tract.
Vomiting, aspiration, diarrhea, fistula, paralytic ileus, blood loss.
35
Give an example of abnormal sodium loss via the renal tract.
Diuretic therapy, osmotic diuresis, renal tubular disease, mineralocorticoid deficiency
36
What are the main categories of causes for excess sodium?
Excessive intake and renal retention.
37
Give an example of excessive sodium intake (oral).
Sea water (drowning), salt tablets, hypertonic NaCl infusion.
38
Give an example of excessive sodium intake (parenteral).
Post-operatively, infusion of hypertonic NaCl.
39
Give an example of renal retention of sodium.
Acute and chronic renal failure, primary and secondary hyperaldosteronism, Cushing's syndrome.
40
Why is sodium important in regulating water balance?
Sodium is the major companion in the extracellular fluid.
41
What are the causes and symptoms of hyponatremia (low sodium levels)?
Causes: Diuretics, GI fluid loss, excess water intake
Symptoms: Nausea, vomiting, confusion, seizures
42
What are the causes and symptoms of hypernatremia (high sodium levels)?
Causes: Dehydration, diabetes insipidus, hypertonic tube feeding
Symptoms: Thirst, hallucinations, lethargy
43
What are the ECG changes in hypokalemia (low potassium levels)?
Low, flat T-waves, ST depression, U waves
44
What are the ECG changes in hyperkalemia (high potassium levels)?
Peaked T waves, flat P waves, widened QRS, risk of ventricular fibrillation
45
What are some causes of hypocalcemia (low calcium levels)?
Hypoalbuminemia, pancreatitis, vitamin D deficiency, renal insufficiency
46
What are the classic signs of hypocalcemia?
Chvostek’s sign, Trousseau’s sign, prolonged QT interval on ECG
47
What are the symptoms of hypercalcemia (high calcium levels)?
Nausea, confusion, lethargy, kidney stones, muscle weakness
48
What are the causes of hypermagnesemia?
Renal insufficiency, excessive antacid use
49
What is the normal pH range of the blood?
7.35 - 7.45
50
what is the conc of H+ in our bloodstream?
7.4
51
What are acids in terms of proton(H+) donation?
Acids are H⁺ donors.
52
What are bases in terms of proton (H⁺) acceptance?
Bases are H⁺ acceptors or give up OH⁻ in solution.
53
How do strong acids and bases behave in solution?
They dissociate completely in solution.
54
How do weak acids and bases behave in solution?
They dissociate only partially in solution.
55
Give an example of a strong acid or base.
HCl (hydrochloric acid) or NaOH (sodium hydroxide).
56
Give an example of a weak acid.
Lactic acid or carbonic acid.
57
What concept relates to acids and bases releasing or absorbing H⁺?
The buffer system.
58
What is the pH level at which death occurs?
Below 6.8 or above 8.0
59
What is the condition called when blood pH drops below 7.35?
Acidosis (acidemia)
60
What is the condition called when blood pH rises above 7.45?
Alkalosis (alkalemia)
61
Why is pH balance important for enzymes?
Enzymes function at specific pH levels; changes in pH can alter their conformation and reduce catalytic activity.
62
How does pH affect oxygen transport in the blood?
Low pH causes hemoglobin to release more O₂ to tissues, while high pH reduces O₂ release, potentially leading to hypoxia.
63
How does acid-base balance affect electrolytes?
It can impact electrolyte levels such as Na⁺, K⁺, and Cl⁻, disrupting cellular functions.
64
What are three sources of acids in the body?
Acids from food, acids from metabolism of lipids and proteins, and CO₂ from cellular metabolism.
65
What reaction links CO₂ to acid production in the body?
CO₂ + H₂O ↔ H₂CO₃ ↔ H⁺ + HCO₃⁻
66
How is CO₂ removed from the body to help maintain pH?
Through respiration (exhalation of CO₂).
67
What happens if CO₂ is not properly exhaled?
It accumulates in the blood, forming carbonic acid, which lowers pH and can lead to acidosis.
68
What are the three main mechanisms for pH regulation in the body?
chemicalBuffer systems, respiratory mechanisms, renal mechanisms
69
What is the first line of defense against pH shifts?
Chemical buffer systems
70
Name three types of chemical buffer systems.
Bicarbonate buffer system, Phosphate buffer system, Protein buffer system
71
What is the second line of defense against pH shifts?
Physiological buffer systems
72
What are the two physiological buffer mechanisms?
Respiratory mechanism (CO₂ excretion) and Renal mechanism (H⁺ excretion)
73
How do buffer systems resist changes in pH?
By taking up or releasing H⁺ ions as needed
74
What is the most important buffer system in the body?
Bicarbonate buffer system (HCO3- / H2CO3)
75
What are the components of the bicarbonate buffer system?
Sodium bicarbonate (NaHCO₃) and carbonic acid (H₂CO₃).
76
What is the ratio of HCO₃⁻ to H₂CO₃ in the bicarbonate buffer system?
20:1
77
What happens when HCl is added to the bicarbonate buffer system?
HCl reacts with NaHCO₃ to form H₂CO₃ and NaCl.
78
What happens when NaOH is added to the bicarbonate buffer system?
NaOH reacts with H₂CO₃ to form NaHCO₃ and H₂O.
79
What enzyme catalyzes the breakdown of H₂CO₃ into CO₂ and H₂O?
Carbonic anhydrase.
80
What is the main function of the phosphate buffer system?
It acts as a major intracellular buffer.
81
What is the chemical equation for the phosphate buffer system when it reacts with H⁺?
H⁺ + HPO₄²⁻ ↔ H₂PO₄⁻
82
What is the chemical equation for the phosphate buffer system when it reacts with OH⁻?
OH⁻ + H₂PO₄⁻ ↔ H₂O + HPO₄²⁻
83
What are the major protein buffers in the body?
Hemoglobin and plasma proteins.
84
How do carboxyl groups in proteins act as buffers?
They give up H⁺ ions when the pH increases.
85
How do amino groups in proteins act as buffers?
They accept H⁺ ions and become NH₃⁺ when the pH decreases.
86
How many amino acids in proteins have side chains that can act as buffers?
27 amino acids.
87
How does respiration help regulate pH?
By exhaling CO₂, which removes carbonic acid from the blood.
88
How does the respiratory system help regulate pH?
By adjusting CO2 levels through breathing rate and depth
89
What type of acids can respiratory mechanisms regulate?
Volatile acids (like carbonic acid).
90
What type of acids cannot be regulated by the respiratory system?
Fixed acids like lactic acid.
91
What is the chemical equation for CO₂ regulation in the blood?
CO₂ + H₂O ↔ H₂CO₃ ↔ H⁺ + HCO₃⁻
92
How do the kidneys help regulate pH?
By excreting acids and bases and conserving bicarbonate ions.
93
What happens if the kidneys fail?
pH balance in the body fails.
94
What ions do the kidneys conserve to regulate pH?
Bicarbonate ions (HCO₃⁻).
95
How fast do buffer systems work?
Almost instantaneously.
96
How long do respiratory mechanisms take to regulate pH?
Several minutes to hours.
97
How long do renal mechanisms take to regulate pH?
Several hours to days.
98
What pH value indicates acidosis?
pH < 7.35
99
What pH value indicates alkalosis?
pH > 7.45
100
What is the body's response to an acid-base imbalance called?
Compensation
101
What is the goal of compensation in an acid-base imbalance?
To eliminate H+ or HCO3- (bicarbonate) to restore pH balance.
102
What is complete compensation?
When the pH is brought back within normal limits.
103
What is partial compensation?
When the pH is still outside the normal range, but moving towards it.
104
What organ systems are involved in regulating acid-base balance, as shown in the diagram?
Lungs and Kidneys
105
How do the lungs contribute to acid-base balance?
By regulating the amount of CO2 given off through respiration (rate and depth).
106
How do the kidneys contribute to acid-base balance?
By regulating the rate of H+ secretion.
107
What is the role of erythrocytes (red blood cells) in the circulation diagram?
They carry CO2 which can be converted to H+ and HCO3- ions.
108
Where is the respiratory center located that controls breathing?
Brain stem
109
What happens to CO2 in the presence of H2O inside an erythrocyte?
It forms H2CO3 (carbonic acid), which then dissociates into H+ and HCO3- ions.
110
How can the kidneys eliminate H+ ions?
By excreting them in urine.
111
What happens to carbonic acid (H2CO3) at high levels?
It dissociates, releasing H+ ions.
112
What happens to H+ ions when carbonic acid dissociates?
They cause acidosis.
113
Why does HCO3- (bicarbonate) decrease in acidosis?
Because the reaction shifts to form more H2CO3, using up bicarbonate. (Form reverse rxn)
114
What are the blood gas results in acidosis?
H+ is elevated (increased).
115
What are the blood gas results in alkalosis?
H+ is decreased.
116
What happens to HCO3- in metabolic acidosis?
HCO3- decreases.
117
What happens to HCO3- in metabolic alkalosis?
HCO3- increases.
118
What is the aim of hyperventilation during acidosis?
To accelerate the removal of CO2
119
What is compensation?
The body's response to an acid-base imbalance to restore pH balance.
120
What type of compensation occurs for a metabolic problem?
Respiratory compensation (hyperventilation or hypoventilation).
121
What type of compensation occurs for a respiratory problem?
Renal mechanisms (metabolic compensation).
122
What is the purpose of compensation?
To bring the pH back to normal by eliminating H+ or HCO3-.
123
How does hyperventilation help in acidosis?
It removes CO2, shifting the equilibrium to reduce H+ ions.
124
How does the body compensate for metabolic acidosis?
By hyperventilating to blow off CO2.
125
How does the body compensate for metabolic alkalosis?
By hypoventilating to retain CO2.
126
How do the kidneys compensate for respiratory acidosis?
By excreting more H+ and reabsorbing more HCO3-.
127
How do the kidneys compensate for respiratory alkalosis?
By reabsorbing more H+ and excreting more HCO3-.
128
What happens to PCO2 in metabolic acidosis?
PCO2 decreases.
129
What happens to H+ concentration in metabolic acidosis?
H+ concentration increases ([H+]↑).
130
What happens to HCO3- concentration in metabolic acidosis?
HCO3- concentration decreases ([HCO3-]↓).
131
formula for acid base disorder
[H+] = PCO2/ [HCO3-]
132
What compensatory mechanism occurs in metabolic acidosis?
Increased ventilation (respiratory compensation).
133
What happens to PCO2 in metabolic alkalosis?
PCO2 increases.
134
What happens to H+ concentration in metabolic alkalosis?
H+ concentration decreases ([H+]↓).
135
What happens to HCO3- concentration in metabolic alkalosis?
HCO3- concentration increases ([HCO3-]↑).
136
What compensatory mechanism occurs in metabolic alkalosis?
Decreased ventilation (respiratory compensation).
137
What is the principal effect of acidosis on the nervous system?
Depression of the CNS through decreased synaptic transmission.
138
What are some general symptoms of acidosis?
Generalized weakness, deranged CNS function.
139
What are some severe effects of acidosis?
Disorientation, coma, death.
140
Why is deranged CNS function the greatest threat in acidosis?
Because it can lead to severe neurological complications and death.
141
What does the diagram in Figure 21.2 illustrate?
Compensation in primary metabolic disorders (acidosis and alkalosis).
142
What is the speed of respiratory compensation in metabolic disorders?
It occurs quickly.
143
What is the relationship between PCO2 and ventilation?
In acidosis, PCO2 decreases with increased ventilation; in alkalosis, PCO2 increases with decreased ventilation.
144
What effect does alkalosis have on the nervous system?
Over excitability of the central and peripheral nervous systems.
145
What are some common symptoms of alkalosis?
Numbness, nervousness, lightheadedness.
146
What are some severe consequences of alkalosis?
Muscle spasms or tetany, convulsions, loss of consciousness, death.
147
What pH level is dangerously high in alkalosis?
pH goes above 8.
148
What are some reasons for metabolic acidosis?
Increased H+ production or ingestion, impaired H+ excretion, loss of HCO3-.
149
What are some reasons for metabolic alkalosis?
Loss of H+ in vomit, alkali ingestion, potassium deficiency.
150
What happens to the reaction direction when there is metabolic acidosis?
The reaction goes in a forward direction.
151
What does Figure 21.3 illustrate?
Reasons for metabolic acidosis and alkalosis.
152
What are some specific causes of increased H+ production or ingestion?
diabetic ketoacidosis, lactic acidosis, aspirin overdose
153
What are some specific causes of impaired H+ excretion?
kidney failure or certain medications
154
What are some specific causes of alkali ingestion?
Taking too much antacid or bicarbonate overdose
155
How does potassium deficiency contribute to metabolic alkalosis?
It can lead to increased renal H+ excretion and increased HCO3- reabsorptio
156
What causes acidosis?
Accumulation of acids or loss of bases, leading to increased concentration of H+.
157
What causes alkalosis?
Loss of acids or accumulation of bases, leading to decreased concentration of H+.
158
What is respiratory acidosis?
Carbonic acid excess caused by blood levels of CO2 above 45 mm Hg.
159
What is hypercapnia?
High levels of CO2 in blood.
160
What are some chronic conditions that can lead to respiratory acidosis?
Depression of respiratory center in the brain (drugs or head trauma), paralysis of respiratory or chest muscles, emphysema.
161
What is the normal range of CO2 in the blood?
below 45 mm Hg
162
What is hypercapnia?
High levels of CO2 in blood.
163
What are some chronic conditions that can lead to respiratory acidosis?
Depression of respiratory center in the brain (drugs or head trauma), paralysis of respiratory or chest muscles, emphysema.
164
How does depression of the respiratory center lead to respiratory acidosis?
It reduces breathing rate, leading to CO2 retention.
165
How does paralysis of respiratory or chest muscles lead to respiratory acidosis?
It impairs the ability to exhale CO2 effectively.
166
How does emphysema lead to respiratory acidosis?
It damages the lungs, impairing gas exchange and leading to CO2 retention.
167
What is the primary acid involved in respiratory acidosis?
Carbonic acid (H2CO3)
168
What is the relationship between CO2 levels and carbonic acid?
Increased CO2 leads to increased carbonic acid.
169
What is the role of the respiratory center in the brain?
Controls breathing rate.
170
Can respiratory acidosis be temporary?
Yes
171
What are some acute conditions that can cause respiratory acidosis?
Adult Respiratory Distress Syndrome (ARDS), pulmonary edema, pneumothorax.
172
How do the kidneys compensate for respiratory acidosis?
They eliminate hydrogen ions (H+) and retain bicarbonate ions (HCO3-
173
Why do the kidneys retain bicarbonate ions in respiratory acidosis?
So that bicarbonate can be continuously available to bind to excessive H+.
174
What is Adult Respiratory Distress Syndrome (ARDS)?
severe lung condition causing fluid buildup in the air sacs, impairing gas exchange.
175
What is pulmonary edema?
fluid accumulation in the lungs, making it difficult to breathe
176
What is pneumothorax?
collapsed lung due to air leaking into the space between the lung and chest wall.
177
What is the role of hydrogen ions in acidosis?
They increase the acidity of the blood.
178
What is the role of bicarbonate ions in buffering acidity?
They act as a buffer by binding to excess hydrogen ions.
179
Why is compensation important in respiratory acidosis?
To restore the pH balance of the blood.
180
What is the primary problem in respiratory acidosis?
Increased CO2 levels in the blood.
181
How does increased CO2 lead to increased H+?
CO2 combines with water to form carbonic acid, which dissociates into H+ and bicarbonate ions.
182
183
184
What are the signs and symptoms of respiratory acidosis?
Breathlessness
Restlessness
Coma
Respiratory rate rapid, then gradually depressed
Skin warm and flushed due to vasodilation caused by excess CO2
185
What are the treatments for respiratory acidosis?
Restore ventilation
IV lactate solution
Treat underlying dysfunction or disease
186
Why does respiratory acidosis cause skin to be warm and flushed?
Due to vasodilation caused by excess CO2.
187
What happens to the respiratory rate in respiratory acidosis?
It initially increases rapidly, then gradually becomes depressed.
188
What happens to the pCO2 levels in respiratory alkalosis?
pCO2 levels decrease to less than 35 mm Hg (hypocapnea)
189
What is the most common acid-base imbalance condition?
Respiratory Alkalosis
190
What is the underlying deficit in respiratory alkalosis?
Carbonic acid deficit
191
List some conditions that stimulate the respiratory center and can lead to respiratory alkalosis
Fever
Oxygen deficiency
192
How does hyperventilation lead to respiratory alkalosis?
Hyperventilation causes excessive removal of CO2 from the body, leading to a decrease in carbonic acid and an increase in pH (making the blood more alkaline).
193
How do the kidneys compensate for respiratory alkalosis?
Conserve hydrogen ions (H+) - does not excrete H+ (a mechanism to retain H+)
Excrete bicarbonate ions (HCO3-)
194
What is the defining characteristic of metabolic acidosis?
Bicarbonate deficit - blood concentrations of bicarb drop below 22 mEq/L.
195
What are the main causes of metabolic acidosis?
Loss of bicarbonate through diarrhea or renal dysfunction
Accumulation of acids (lactic acid or ketones)
Failure of kidneys to excrete H+
196
What are the symptoms of metabolic acidosis?
Diarrhea
197
How does diarrhea lead to metabolic acidosis?
Diarrhea causes a loss of bicarbonate from the body, leading to a decrease in blood bicarbonate levels and metabolic acidosis.
198
How can renal dysfunction cause metabolic acidosis?
The kidneys are responsible for regulating bicarbonate levels and excreting acids.
If they fail to function properly, they can't excrete H+ or reabsorb bicarbonate, leading to acidosis.
199
What are the potential consequences of untreated metabolic acidosis?
Coma and death.
200
How does the body compensate for metabolic acidosis?
Increased ventilation
Renal excretion of hydrogen ions (H+) if possible
Potassium (K+) exchanges with excess hydrogen ions (H+) in the extracellular fluid (ECF) (H+ into cells, K+ out of cells)
201
Why does increased ventilation help compensate for metabolic acidosis?
Increased ventilation helps blow off excess CO2, which reduces the amount of carbonic acid in the blood, helping to raise the pH.
202
How do the kidneys compensate for metabolic acidosis?
By excreting hydrogen ions (H+) if possible.
203
Explain the potassium (K+) and hydrogen ion (H+) exchange in metabolic acidosis compensation.
In metabolic acidosis, excess hydrogen ions (H+) in the extracellular fluid (ECF) move into cells, and potassium ions (K+) move out of cells into the ECF to maintain electrical neutrality.
204
What is the defining characteristic of metabolic alkalosis?
Bicarbonate excess - concentration in blood is greater than 26 mEq/L.
205
What are the common causes of metabolic alkalosis?
Excess vomiting (loss of stomach acid)
Excessive use of alkaline drugs
Certain diuretics
206
Why does excess vomiting lead to metabolic alkalosis?
Vomiting causes a loss of stomach acid (hydrochloric acid), leading to an increase in bicarbonate levels in the blood.
207
Why is the renal compensation for metabolic alkalosis often ineffective?
Metabolic alkalosis most commonly occurs with renal dysfunction, so the kidneys cannot effectively regulate bicarbonate levels.
208
Why is respiratory compensation for metabolic alkalosis difficult?
Respiratory compensation (hypoventilation) is limited by hypoxia (low oxygen levels). The body's drive to breathe is primarily controlled by oxygen levels, so significant hypoventilation is difficult to achieve.
209
How can severe dehydration contribute to metabolic alkalosis?
Severe dehydration can lead to a relative increase in bicarbonate concentration in the blood, contributing to metabolic alkalosis.
210
Why are slow and shallow respirations a symptom of metabolic alkalosis?
The body attempts to compensate for the alkalosis by retaining CO2, which is achieved through decreased ventilation.
