Chapter 05: Fluids and Electrolytes, Acids and Bases

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Questions and Answers

What is the primary mechanism by which water moves between the intracellular and extracellular fluid compartments?

Osmosis (correct)

Active transport

Diffusion

Filtration

Which factor is NOT associated with the pathophysiological process leading to edema?

Increased vascular volume

Arterial dilation

Increased capillary permeability

Decreased blood pressure (correct)

How is sodium balance primarily regulated in the body?

By the action of aldosterone (correct)

Via antidiuretic hormone

Through natriuretic peptides

Through the sensation of thirst

What occurs as a result of increased hydrostatic pressure in the capillaries?

Increased movement of fluids into the interstitial space Signup and view all the answers

Which of the following describes a situation with hypotonic fluid alterations?

Decreased extracellular fluid osmolality Signup and view all the answers

What hormone is secreted in response to an increase in plasma osmolality?

Antidiuretic hormone Signup and view all the answers

What condition is characterized by an accumulation of fluid in interstitial spaces?

Edema Signup and view all the answers

Which of the following accurately describes the relationship between sodium and chloride levels?

Chloride levels are generally proportional to sodium levels. Signup and view all the answers

What role do renin and angiotensin play in sodium regulation?

They promote secretion of aldosterone. Signup and view all the answers

Which statement regarding edema is true?

It can result from venous obstruction. Signup and view all the answers

What is hypernatremia primarily associated with?

Increased concentration of ECF sodium or deficit of ECF water Signup and view all the answers

What defines hyponatremia in terms of sodium concentration?

Serum sodium concentration of less than 135 mmol/L Signup and view all the answers

Which condition is characterized by an excess of sodium or a deficit of plasma bicarbonate?

Hyperchloremia Signup and view all the answers

Which electrolyte imbalance may lead to an increase in the level of noncarbonic acids or loss of bicarbonate?

Metabolic acidosis Signup and view all the answers

What condition can result from hypokalemia?

Normal plasma potassium levels despite depletion Signup and view all the answers

Which of the following is TRUE regarding hypercalcemia?

Can lead to bone metastases or is related to vitamin D excess Signup and view all the answers

How does the body primarily regulate potassium balance?

Through the kidney, aldosterone, and insulin secretion Signup and view all the answers

What is the role of buffers in the body regarding pH?

They can absorb excessive acid or base without significant pH change Signup and view all the answers

Which is a likely cause of hyperphosphatemia?

Chronic kidney failure leading to loss of glomerular filtration Signup and view all the answers

Which system primarily compensates for changes in blood pH?

Renal and respiratory systems Signup and view all the answers

Study Notes

Distribution of Body Fluids and Electrolytes

Total Body Water (TBW) varies by age and body fat percentage.
Body fluids are categorized into intracellular fluid (ICF) and extracellular fluid (ECF).
Osmosis primarily governs the movement of water between ICF and ECF.
Plasma and interstitial fluid exchange occurs via osmosis and hydrostatic pressure across the capillary membrane, termed net filtration.
Starling forces describe this filtration process, balancing hydrostatic and osmotic pressures.

Alterations in Water Movement

Edema results from excess fluid in interstitial spaces.
Causes of edema include increased fluid filtration from capillaries, arterial dilation, venous or lymphatic obstruction, elevated vascular volume, and increased capillary permeability.
Symptoms of edema include weight gain, swelling, tighter clothing, and restricted movement.

Sodium, Chloride, and Water Balance

Sodium and water balance are closely linked; chloride levels typically parallel sodium levels.
Thirst sensation and antidiuretic hormone (ADH) control water balance, responding to plasma osmolality and blood volume changes.
Aldosterone regulates sodium by enhancing reabsorption through the kidneys.
Renin and angiotensin stimulate aldosterone secretion, thus influencing sodium and water balance.
Natriuretic peptides promote sodium excretion and reduce tubular reabsorption.

Alterations in Sodium, Water, and Chloride Balance

Changes in sodium and water can be isotonic, hypertonic, or hypotonic.
Isotonic alterations manifest as equal changes in TBW and electrolytes.
Hypertonic alterations occur with elevated ECF osmolality due to high sodium or low water levels.
Hypernatremia (sodium > 145 mmol/L) results from acute sodium increases or water loss, presenting as isovolemic, hypovolemic, or hypervolemic.
Hyponatremia (sodium < 135 mmol/L) leads to water influx into cells, caused by sodium loss, inadequate intake, or excessive water.
Hypochloremia is typically a consequence of hyponatremia or high bicarbonate.

Alterations in Potassium and Other Electrolytes

Potassium, the main ICF ion, regulates osmolality and maintains the resting membrane potential.
Kidney function, aldosterone, insulin, and pH levels control potassium balance.
Hypokalemia (potassium < 3.5 mmol/L) reflects total potassium loss; can arise from reduced intake, shifts to ICF, increased secretion, or alkalosis.
Hyperkalemia (potassium > 5.0 mmol/L) results from excess intake, shifts from ICF, or reduced renal function.
Calcium is essential for bone formation, blood coagulation, and cellular functions; regulated by parathyroid hormone (PTH), vitamin D, and calcitonin.
Hypocalcemia (< 2.1 mmol/L) can stem from poor absorption, tissue deposition, or reduced PTH/vitamin D.
Hypercalcemia (> 2.6 mmol/L) may be linked to conditions like hyperparathyroidism or excess vitamin D.
Phosphate, crucial for energy and buffering, can cause hypophosphatemia (reduced absorption) or hyperphosphatemia (renal failure).
Magnesium is primarily intracellular; hypomagnesemia (< 0.75 mmol/L) often results from malabsorption, while hypermagnesemia (> 1.25 mmol/L) is rare and linked to renal failure.

Acid–Base Balance

Hydrogen ion concentration ([H+]) is crucial for enzymatic reactions and is represented by pH, where values < 7.4 are acidic and > 7.4 are alkaline.
Acid–base balance is regulated by the renal and respiratory systems and buffered by substances like carbonic acid and bicarbonate.
Compensation regulates pH by adjusting ventilation and urine acidity, while correction restores normal buffer pairs.
Acidosis and alkalosis arise from shifts in hydrogen ion concentration and bicarbonate levels.
Metabolic acidosis results from noncarbonic acid accumulation or bicarbonate loss; metabolic alkalosis arises from bicarbonate retention.
Respiratory acidosis occurs from decreased ventilation (hypercapnia), while respiratory alkalosis stems from hyperventilation (hypocapnia).

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Description

Test your understanding of fluids and electrolytes based on Chapter 05 of Huether's 'Understanding Pathophysiology'. This quiz covers the distribution of body fluids, the differences between intracellular and extracellular fluid, and the principles of osmosis. Perfect for students eager to reinforce their knowledge in pathophysiology.