Podcast
Questions and Answers
What is the main determinant of extracellular fluid (ECF) volume?
What is the main determinant of extracellular fluid (ECF) volume?
- Chloride (Cl-)
- Magnesium (Mg2+)
- Potassium (K+)
- Sodium (Na+) (correct)
What accounts for nearly all the osmotically active solute in plasma and interstitial fluid?
What accounts for nearly all the osmotically active solute in plasma and interstitial fluid?
- Potassium (K+)
- Calcium (Ca2+)
- Sodium (Na+) (correct)
- Chloride (Cl-)
What is the approximate total body content of Na+ in mmol?
What is the approximate total body content of Na+ in mmol?
- 4000 mmol (correct)
- 2000 mmol
- 3000 mmol
- 5000 mmol
How much of the total body Na+ content is intracellular?
How much of the total body Na+ content is intracellular?
Where is Na+ mainly reabsorbed in the nephron?
Where is Na+ mainly reabsorbed in the nephron?
Which hormone influences active Na+ absorption in the small intestine and colon?
Which hormone influences active Na+ absorption in the small intestine and colon?
What is the primary action of PTH when ionized Ca2+ levels decrease?
What is the primary action of PTH when ionized Ca2+ levels decrease?
What is the final step in the manufacture of active vitamin D (calcitriol)?
What is the final step in the manufacture of active vitamin D (calcitriol)?
What is the primary effect of hyperphosphatemia on calcium homeostasis?
What is the primary effect of hyperphosphatemia on calcium homeostasis?
What percentage of circulating calcium is in the biologically active ionized form?
What percentage of circulating calcium is in the biologically active ionized form?
What is one of the mechanisms that may lead to hyperkalemia in organic acidemia?
What is one of the mechanisms that may lead to hyperkalemia in organic acidemia?
What is the primary cellular action of magnesium (Mg2+) that highlights its diverse clinical applications?
What is the primary cellular action of magnesium (Mg2+) that highlights its diverse clinical applications?
Which cell type in the collecting ducts is responsible for the regulation of potassium (K+) secretion under the influence of aldosterone?
Which cell type in the collecting ducts is responsible for the regulation of potassium (K+) secretion under the influence of aldosterone?
How do principal cells influence potassium (K+) secretion in the collecting ducts?
How do principal cells influence potassium (K+) secretion in the collecting ducts?
What is the approximate percentage of total body magnesium found in the extracellular fluid (ECF)?
What is the approximate percentage of total body magnesium found in the extracellular fluid (ECF)?
What is the main reason for hypokalemia associated with diuretics that increase distal tubular Na+ content?
What is the main reason for hypokalemia associated with diuretics that increase distal tubular Na+ content?
How does acidemia affect the degree of albumin-protein binding of calcium?
How does acidemia affect the degree of albumin-protein binding of calcium?
How do intercalated cells respond in low potassium (K+) settings?
How do intercalated cells respond in low potassium (K+) settings?
What is the primary role of magnesium (Mg2+) in energy metabolism?
What is the primary role of magnesium (Mg2+) in energy metabolism?
Which hormone is essential for maintaining serum calcium concentrations between 4.5 and 5 mEq/L?
Which hormone is essential for maintaining serum calcium concentrations between 4.5 and 5 mEq/L?
What is the role of Ca2+ in coagulation processes?
What is the role of Ca2+ in coagulation processes?
How is cytoplasmic free Ca2+ kept low in cells?
How is cytoplasmic free Ca2+ kept low in cells?
What is the dominant intracellular cation in the body?
What is the dominant intracellular cation in the body?
What is the primary mechanism involved in excretion of total body excess Na+ mentioned in the text?
What is the primary mechanism involved in excretion of total body excess Na+ mentioned in the text?
How does low potassium intake combined with chronic action of digitalis-like factor contribute to hypertension?
How does low potassium intake combined with chronic action of digitalis-like factor contribute to hypertension?
What is the primary role of K+ in excitable tissues according to the text?
What is the primary role of K+ in excitable tissues according to the text?
Which process involves shifts in K+ between extracellular fluid (ECF) and intracellular fluid (ICF)?
Which process involves shifts in K+ between extracellular fluid (ECF) and intracellular fluid (ICF)?
How does insulin influence intracellular levels of Na+ and K+?
How does insulin influence intracellular levels of Na+ and K+?
How do catecholamines influence K+ handling in muscles?
How do catecholamines influence K+ handling in muscles?
What is the primary function of cell membrane Na+/K+ ATPase according to the text?
What is the primary function of cell membrane Na+/K+ ATPase according to the text?
What is the primary role of Mg2+ in maintaining normal transmembrane electrochemical gradients?
What is the primary role of Mg2+ in maintaining normal transmembrane electrochemical gradients?
How does Mg2+ antagonize the effects of Ca2+ physiologically (physiologic competitive antagonism of Ca2+)?
How does Mg2+ antagonize the effects of Ca2+ physiologically (physiologic competitive antagonism of Ca2+)?
How does Mg2+ antagonize NMDA receptors in the central nervous system?
How does Mg2+ antagonize NMDA receptors in the central nervous system?
What is the primary mechanism of Mg2+ absorption ?
What is the primary mechanism of Mg2+ absorption ?
What is the main determinant of total body Mg2+ levels?
What is the main determinant of total body Mg2+ levels?
How do catecholamines and glucagon affect the intracellular-extracellular balance of magnesium distribution?
How do catecholamines and glucagon affect the intracellular-extracellular balance of magnesium distribution?
What is the primary function of phosphate in energy metabolism?
What is the primary function of phosphate in energy metabolism?
Which molecule is formed with the help of phosphate?
Which molecule is formed with the help of phosphate?
Where is the majority of total body phosphorus stored?
Where is the majority of total body phosphorus stored?
How is GI uptake of phosphate primarily achieved?
How is GI uptake of phosphate primarily achieved?
Which form of inorganic phosphate predominates in the plasma at normal pH?
Which form of inorganic phosphate predominates in the plasma at normal pH?
What happens to postprandial increases in serum phosphate levels according to the text?
What happens to postprandial increases in serum phosphate levels according to the text?
What is the primary regulator of phosphate (PO43-) absorption in the intestine and kidneys?
What is the primary regulator of phosphate (PO43-) absorption in the intestine and kidneys?
What is the primary role of chloride (Cl-) in the body?
What is the primary role of chloride (Cl-) in the body?
How is chloride (Cl-) primarily excreted from the body?
How is chloride (Cl-) primarily excreted from the body?
Which cells in the distal nephron are responsible for regulated control of chloride (Cl-) excretion?
Which cells in the distal nephron are responsible for regulated control of chloride (Cl-) excretion?
What is the primary action of parathyroid hormone (PTH) on phosphate (PO43-) handling?
What is the primary action of parathyroid hormone (PTH) on phosphate (PO43-) handling?
What is the primary mechanism by which gastrointestinal (GI) secretions are formed?
What is the primary mechanism by which gastrointestinal (GI) secretions are formed?
what is the normal sodium concentration gradient between the intracellular and extracellular compartments
what is the normal sodium concentration gradient between the intracellular and extracellular compartments
sodium concentration gradient between the intracellular and extracellular compartments is maintained by: ATPases and is vital for
sodium concentration gradient between the intracellular and extracellular compartments is maintained by: ATPases and is vital for
maintaining SODIUM concentration gradient is vital for the function of:
maintaining SODIUM concentration gradient is vital for the function of:
daily Na+ intake is
daily Na+ intake is
which route is the predominant for Na loss
which route is the predominant for Na loss
what is the correct matching for systems involved in the control of circulating volume
what is the correct matching for systems involved in the control of circulating volume
what is the correct matching for systems involved in the control of circulating volume
what is the correct matching for systems involved in the control of circulating volume
Daily requirements of K?
Daily requirements of K?
daily K+ intake is a similar magnitude to ?
daily K+ intake is a similar magnitude to ?
Transmembrane potentials particularly depend on K+ permeability. how Transmembrane potentials achieved ?
Transmembrane potentials particularly depend on K+ permeability. how Transmembrane potentials achieved ?
what is the function of skeletal muscle in the presence of hypokalemia
what is the function of skeletal muscle in the presence of hypokalemia
Other factors that may influence ECF to ICF K+ balance ?
Other factors that may influence ECF to ICF K+ balance ?
In addition to mechanisms involving aldosterone in a feedback loop, it is likely that feed-forward mechanisms also exist, what is the main function of feed-forward mechanisms.
In addition to mechanisms involving aldosterone in a feedback loop, it is likely that feed-forward mechanisms also exist, what is the main function of feed-forward mechanisms.
where its found the calcium major storage
where its found the calcium major storage
calcium play important role in?
calcium play important role in?
Increases in cytoplasmic Ca2+ concentration is
Increases in cytoplasmic Ca2+ concentration is
the kidney covert 25-hydroxy-calciferol to 1,25-dihydroxycalciferol (calcitriol) under the influence of PTH. wha is the main action of the active vit D(calcitriol) ?
the kidney covert 25-hydroxy-calciferol to 1,25-dihydroxycalciferol (calcitriol) under the influence of PTH. wha is the main action of the active vit D(calcitriol) ?
which other electrolytes can affect Ca2+ homeostasis ?
which other electrolytes can affect Ca2+ homeostasis ?
you are in the OR and the surgeon ask if you can take a blood sample to check the calcium level ? what is the best way to take the sample?
you are in the OR and the surgeon ask if you can take a blood sample to check the calcium level ? what is the best way to take the sample?
what is the primary intracellular anion
what is the primary intracellular anion
why the Free ionized Mg2+ levels within the cytoplasm and ECF are low ?
why the Free ionized Mg2+ levels within the cytoplasm and ECF are low ?
Within the plasma, where is the majority of Mg2+ is found
Within the plasma, where is the majority of Mg2+ is found
magnesium Excretion is via?
magnesium Excretion is via?
75% of magnesium is freely filtered at the glomerulus, what is the primary tubule for reabsorption.
75% of magnesium is freely filtered at the glomerulus, what is the primary tubule for reabsorption.
what is the effect of adrenergic stimulation on magnesium?
what is the effect of adrenergic stimulation on magnesium?
of total body magnesium, majority found in?
of total body magnesium, majority found in?
another important function of phosphate in body
another important function of phosphate in body
which type of phosphate normally found in plasma?
which type of phosphate normally found in plasma?
which type of phosphate normally found intracellular ?
which type of phosphate normally found intracellular ?
typical daily intake of phosphate is
typical daily intake of phosphate is
what is the main mechanism of GI uptake
what is the main mechanism of GI uptake
Plasma inorganic PO43− is freely filtered at the glomerulus, at which tubule occur the majority of reabsorption
Plasma inorganic PO43− is freely filtered at the glomerulus, at which tubule occur the majority of reabsorption
what is the main effect of vitamin D on phosphate absorption
what is the main effect of vitamin D on phosphate absorption
what is the main effect of PTH on phosphate absorption
what is the main effect of PTH on phosphate absorption
chloride is the second most abundant electrolyte in the extracellular compartment, therefore responsible for?
chloride is the second most abundant electrolyte in the extracellular compartment, therefore responsible for?
Most Cl− intake is derived from dietary NaCl, and the GI tract absorbs and secretes large amounts of Cl− in the form of?
Most Cl− intake is derived from dietary NaCl, and the GI tract absorbs and secretes large amounts of Cl− in the form of?
how is the GI secretions formed?
how is the GI secretions formed?
What is the normal range for anion gap in the plasma?
What is the normal range for anion gap in the plasma?
In cases of excess organic acids, what leads to an increase in the anion gap?
In cases of excess organic acids, what leads to an increase in the anion gap?
Which model places changes in plasma HCO3− at the core of plasma acid-base balance?
Which model places changes in plasma HCO3− at the core of plasma acid-base balance?
Which ions are represented by 'unmeasured' anions in the anion gap model
Which ions are represented by 'unmeasured' anions in the anion gap model
In the presence of excess Cl− administration, what happens to the anion gap even if HCO3− falls?
In the presence of excess Cl− administration, what happens to the anion gap even if HCO3− falls?
According to the Stewart model, which of the following is NOT an independent variable that determines plasma pH?
According to the Stewart model, which of the following is NOT an independent variable that determines plasma pH?
What is the normal range for the apparent Strong Ion Difference (SID) in plasma?
What is the normal range for the apparent Strong Ion Difference (SID) in plasma?
How does a reduction in the Strong Ion Difference (SID) affect plasma pH according to the Stewart model?
How does a reduction in the Strong Ion Difference (SID) affect plasma pH according to the Stewart model?
What is the primary advantage of the Stewart model of acid-base balance compared to the traditional approach?
What is the primary advantage of the Stewart model of acid-base balance compared to the traditional approach?
intravascular fluid therapy may affect acid-base by?
intravascular fluid therapy may affect acid-base by?
What did a meta-analysis of studies comparing saline with balanced perioperative fluid regimes confirm?
What did a meta-analysis of studies comparing saline with balanced perioperative fluid regimes confirm?
What was associated with significant hyperkalemia in a trial involving patients undergoing renal transplants?
What was associated with significant hyperkalemia in a trial involving patients undergoing renal transplants?
In the emergency department and intensive care settings, which group of patients showed the greatest effect from receiving saline compared to balanced crystalloid?
In the emergency department and intensive care settings, which group of patients showed the greatest effect from receiving saline compared to balanced crystalloid?
What is the primary cause of hyperchloremic acidosis during high-volume saline infusion?
What is the primary cause of hyperchloremic acidosis during high-volume saline infusion?
How does lactated Ringer's solution differ from normal saline in terms of its effect on acid-base balance?
How does lactated Ringer's solution differ from normal saline in terms of its effect on acid-base balance?
Which of the following is a potential deleterious effect of saline-induced hyperchloremic acidosis?
Which of the following is a potential deleterious effect of saline-induced hyperchloremic acidosis?
According to the Stewart model, what is the primary determinant of plasma pH?
According to the Stewart model, what is the primary determinant of plasma pH?
Which of the following solutions has an effective strong ion difference (SID) closest to that of plasma?
Which of the following solutions has an effective strong ion difference (SID) closest to that of plasma?
What is the primary mechanism by which saline infusion causes a reduction in plasma bicarbonate concentration?
What is the primary mechanism by which saline infusion causes a reduction in plasma bicarbonate concentration?
IV NaHCO3 to treat metabolic acidosis should be
IV NaHCO3 to treat metabolic acidosis should be
What negative effect does IV HCO3− administration bring due to its significant Na+ content?
What negative effect does IV HCO3− administration bring due to its significant Na+ content?
What is the major challenge posed by the conversion of HCO3− to CO2 when administered in excess?
What is the major challenge posed by the conversion of HCO3− to CO2 when administered in excess?
What role does acidosis play during strenuous exercise according to the text?
What role does acidosis play during strenuous exercise according to the text?
What is the primary reason for HCO3− administration being disputed in critically ill patients?
What is the primary reason for HCO3− administration being disputed in critically ill patients?
What is one of the potential negative effects of administering IV NaHCO3 to treat metabolic acidosis?
What is one of the potential negative effects of administering IV NaHCO3 to treat metabolic acidosis?
What is one potential reason why the clinical benefit of HCO3- administration may not be apparent in many situations?
What is one potential reason why the clinical benefit of HCO3- administration may not be apparent in many situations?
What is one of the negative effects of IV HCO3- administration mentioned in the text?
What is one of the negative effects of IV HCO3- administration mentioned in the text?
What is the main challenge posed by the conversion of administered HCO3- to CO2 according to the text?
What is the main challenge posed by the conversion of administered HCO3- to CO2 according to the text?
when the treatment with bicarbonate should be stoped?
when the treatment with bicarbonate should be stoped?
In situations in which HCO3− administration is required, the total dose required to correct the base deficit can be calculated using
In situations in which HCO3− administration is required, the total dose required to correct the base deficit can be calculated using
treatment with HCO3− due to metabolic acidosis can lead in certain situations to “overshoot” toward metabolic alkalosis. when dose this can occur ?
treatment with HCO3− due to metabolic acidosis can lead in certain situations to “overshoot” toward metabolic alkalosis. when dose this can occur ?
HCO3− total dose required to correct the base deficit can be calculated using the equation: Dose (mEq) =0.3 × weight(kg) × base deficit(mEq/L).
HCO3− total dose required to correct the base deficit can be calculated using the equation: Dose (mEq) =0.3 × weight(kg) × base deficit(mEq/L).
Flashcards are hidden until you start studying
Study Notes
Acid-Base Balance
- Stewart's model proposes that plasma pH is dependent on three independent variables:
- pCO2 (plasma CO2 tension)
- Atot (total plasma concentration of nonvolatile buffers)
- SID (strong ion difference)
- SID is the difference between the total charge of plasma-strong cations (Na+, K+, Mg2+, Ca2+) and strong anions (Cl-, lactate, sulfate, and others)
- Normal plasma SID is approximately 42 mEq/L, and reductions in SID lead to a fall in plasma pH
Henderson-Hasselbach Equation
- Represents the HCO3- buffer system
- Plasma HCO3- concentration is an independent determinant of plasma pH
Anion Gap
- Defined as the difference between the most abundant measured cation and anion concentrations in the plasma ([Na+] + [K+]) - ([Cl-] + [HCO3-])
- Normal anion gap is 4 to 11 mEq/L
- In the presence of excess organic acids, the accumulation of unmeasured anions is accompanied by a reduction in HCO3- to buffer the excess H+ ions, leading to an increase in the anion gap
Hyperchloremic Acidosis
- Caused by the administration of fluid with Cl- concentration higher than that of plasma
- Leads to a metabolic acidosis due to the Cl- content
- Can be explained by the Henderson-Hasselbach model (dilution of bicarbonate and a resultant base deficit) or the Stewart model (reduction of apparent SID and therefore reduction of plasma pH)
Bicarbonate Administration
-
Should be reserved for the emergency treatment of select conditions, such as severe hyperkalemia and arrhythmias associated with tricyclic antidepressant overdose
-
Has negative effects, including:
- Carbon dioxide production
- Osmotic load and hyperosmolar hypernatremia
- ECF expansion and volume overload### Sodium Physiology
-
Serum Na+ concentrations are maintained within a tight range (138-142 mEq/L) despite variations in water intake.
-
The excretion of total body excess Na+ relies on inefficient passive mechanisms, particularly the pressure-volume effect.
-
Long-term ingestion of excess salt combined with low potassium ingestion contributes to hypertension.
Potassium Physiology
- K+ is the dominant intracellular cation in the body, with a total body content of approximately 4000 mmol, 98% of which is intracellular.
- The ratio of ICF to ECF K+ balance is vital in maintaining cellular resting membrane potential.
- Daily requirements reflect age and growth, with more K+ required at higher metabolic rates.
- Transmembrane potentials depend on K+ permeability, with K+ egress occurring through ion channels down its concentration gradient.
Acute K+ Distribution
- Acute K+ distribution involves shifts in K+ between the ECF and ICF, performed by ion transport systems under the influence of insulin, catecholamines, and ECF pH.
- The cell membrane Na+/K+ ATPase exports three Na+ for every two K+ imported and is the means by which the gradients of these ions are maintained.
Magnesium Physiology
- Mg2+ helps maintain normal transmembrane electrochemical gradients, effectively stabilizing cell membranes and organelles.
- Mg2+ also antagonizes Ca2+ and N-methyl-d-aspartate (NMDA) receptors within the central nervous system.
- Mg2+ is absorbed from the GI tract by a saturable transport system and passive diffusion, with excretion via the GI tract and kidneys.
Phosphate Physiology
- PO43− is the most abundant intracellular anion and helps form biologic molecules such as ATP, DNA, and RNA, membrane phospholipids, and hydroxyapatite in bone.
- PO43− is required for energy metabolism, cellular signaling, cellular replication, and protein synthesis.
- Normal plasma inorganic phosphates are maintained at 3 to 5 mg/dL, with most intracellular PO43− being organic.
Chloride Physiology
- Chloride (Cl−) has a key role in maintaining plasma osmolality, preserving electrical neutrality, and acid-base status.
- Normal plasma values are 97 to 107 mEq/L, with Cl− responsible for nearly a third of plasma osmolality and two thirds of plasma negative charge.
- Most Cl− intake is derived from dietary NaCl, and the GI tract absorbs and secretes large amounts of Cl−.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
