40 Questions
What percentage of water content do healthy males typically have?
60%
Where is interstitial fluid found?
In spaces between cells
What is the main fluid compartment contained in cells?
Intracellular fluid (ICF)
What factor contributes to the difference in total water content between healthy males and healthy females?
Higher body fat
What percentage of water content do infants have?
73% or more
What is the fluid portion of the blood called?
Plasma
What is the cause of acidosis in the context of respiratory acid-base imbalance?
High PCO2
How do the kidneys respond to correct respiratory acid-base imbalance?
By retaining bicarbonate to offset the acidosis
What is the water content of the body at adulthood?
About 58%
What slows down with age according to the text?
Homeostatic mechanisms
Who are at risk of dehydration according to the text?
Elders
What reflects problems with fluid, electrolyte, and acid-base balance in the young?
High metabolic rate yielding more metabolic wastes
What triggers thirst according to the text?
Decline in plasma volume or increases in plasma osmolality
What is the primary source of water intake mentioned in the text?
Ingested fluid, solid food, and metabolic water
What is the role of ADH release according to the text?
Regulates water reabsorption in collecting ducts
What is the consequence of dehydration according to the text?
Negative fluid balance
What is hypotonic hydration according to the text?
Result from excessive water intake or renal insufficiency
What is the central position held by sodium according to the text?
In fluid and electrolyte balance
What is the main function of amphoteric molecules in acid-base balance?
Acting as both a weak acid and a weak base
How does the respiratory system regulate acid-base balance?
Through a reversible equilibrium between dissolved carbon dioxide and water, carbonic acid, and hydrogen and bicarbonate ions
What is the ultimate acid-base regulatory organ in the body?
The kidneys
What is the process by which type A intercalated cells generate new bicarbonate ions?
Renal excretion of acid and excretion of hydrogen ions or ammonium ions
What occurs during metabolic alkalosis?
Rising blood pH and bicarbonate levels
When does respiratory alkalosis commonly occur?
As a common result of hyperventilation
What is the role of estrogens in electrolyte balance?
Enhancing NaCl reabsorption by renal tubules
What is the effect of excessive extracellular potassium?
Decreasing membrane potential
How does aldosterone influence potassium ion secretion?
Stimulating potassium ion secretion by principal cells in the cortical collecting ducts
What controls the balance of ionic calcium in extracellular fluid?
Parathyroid hormone (PTH) and calcitonin
How is filtered phosphate reabsorbed in the proximal tubules regulated?
By its transport maximum and influenced by ECF calcium levels
What is the role of the respiratory center in the regulation of hydrogen ions?
Involvement in chemical buffer systems
Acidosis is characterized by low PCO2 and low bicarbonate levels.
False
Elders are more responsive to thirst clues compared to young individuals.
False
Respiratory acid-base imbalance is corrected by renal mechanisms stepping up.
True
The very young and the very old are the least frequent victims of fluid, acid-base, and electrolyte imbalances.
False
Alkalosis is characterized by high PCO2 and low pH.
False
The kidneys eliminate bicarbonate from the body by actively secreting it.
True
Water content of the body is greatest at birth and declines until adulthood.
True
Alkalosis is caused by high bicarbonate levels.
True
The role of the respiratory system in acid-base balance is to eliminate excess hydrogen ions.
True
The kidneys retain bicarbonate to offset acidosis in the body.
True
Study Notes
Regulation of Electrolyte Balance in the Body
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Estrogens enhance NaCl reabsorption by renal tubules and may cause water retention during menstrual cycles and edema during pregnancy.
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Regulation of potassium balance is crucial for maintaining a cell’s resting membrane potential and preventing disruptions in electrical conduction in the heart.
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Excessive extracellular potassium can decrease membrane potential, while low levels of potassium can cause hyperpolarization and nonresponsiveness.
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Cortical collecting ducts play a key role in regulating potassium balance by changing the amount of potassium secreted into the filtrate, with less than 15% of filtered K+ lost to urine regardless of need.
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Plasma potassium concentration influences potassium secretion by the collecting ducts, favoring principal cells to secrete K+ in high ECF K+ content and depresses its secretion in low K+ or accelerated K+ loss.
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Aldosterone stimulates potassium ion secretion by principal cells in the cortical collecting ducts, and increased ECF K+ levels result in the release of aldosterone and potassium secretion.
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Ionic calcium in extracellular fluid is important for blood clotting, cell membrane permeability, and secretory behavior, and its balance is controlled by parathyroid hormone (PTH) and calcitonin.
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PTH promotes an increase in calcium levels by targeting bones, small intestine, and kidneys, with calcium reabsorption and phosphate excretion going hand in hand.
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Filtered phosphate is actively reabsorbed in the proximal tubules, and its reabsorption is regulated by its transport maximum, with high or normal ECF calcium levels inhibiting PTH secretion.
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Chloride is the major anion accompanying sodium in the extracellular fluid, with 99% of chloride reabsorbed under normal pH conditions, and acidosis leading to fewer chloride ions being reabsorbed.
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The normal pH of body fluids is crucial, with arterial blood at 7.4, venous blood and interstitial fluid at 7.35, and intracellular fluid at 7.0, and acidosis or alkalosis can have significant physiological effects.
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The regulation of hydrogen ions involves chemical buffer systems, the respiratory center in the brain stem, and renal mechanisms, with chemical buffer systems including the bicarbonate buffer system, phosphate buffer system, and protein buffer system.
Test your knowledge of the regulation of electrolyte balance in the body with this informative quiz. Explore the roles of hormones, renal mechanisms, and chemical buffer systems in maintaining the balance of sodium, potassium, calcium, phosphate, and chloride ions. Understand the impact of electrolyte imbalances on physiological functions and health.
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