Fluid Balance and Electrolytes / Acid and Base Balances

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Questions and Answers

What is the normal range for potassium levels in mmol/L?

3.5-5.0 (correct)

2.5-3.0

5.0-7.0

4.0-6.0

What condition is indicated by a potassium level greater than 5.0 mmol/L?

Hypochloremia

Hyperkalemia (correct)

Hypokalemia

Hyponatremia

Which of the following symptoms is associated with hypernatremia?

Lethargy

Seizures

Muscle weakness

Thirst (correct)

What term describes a sodium level lower than 135 mmol/L?

Hyponatremia Signup and view all the answers

Which type of solution is considered isotonic?

0.9% saline Signup and view all the answers

What effect does a hypertonic solution have on cells?

Causes cells to shrink Signup and view all the answers

What is a common cause of edema due to increased capillary hydrostatic pressure?

Heart failure Signup and view all the answers

What comprises the majority of total body water (TBW)?

Intracellular Fluid Signup and view all the answers

What is the primary force that pulls water into an area of higher solute concentration?

Osmotic Pressure Signup and view all the answers

What is associated with both hyperchloremia and hyponatremia?

Loss of plasma proteins Signup and view all the answers

What is the role of renin in the Renin-Angiotensin System (RAAS)?

It activates angiotensin I from angiotensinogen. Signup and view all the answers

Which of the following best describes Starling Forces?

They comprise capillary hydrostatic pressure and plasma oncotic pressure. Signup and view all the answers

In what situation would you expect a systemic increase in H+ concentration?

Metabolic Acidosis Signup and view all the answers

What initiates the release of antidiuretic hormone (ADH)?

An increase in plasma osmolality. Signup and view all the answers

What is the normal pH range for human blood?

7.35-7.45 Signup and view all the answers

What causes respiratory acidosis?

Hypoventilation causing increased carbon dioxide levels. Signup and view all the answers

What is one effect of aldosterone in the kidneys?

It promotes potassium secretion. Signup and view all the answers

Which condition is characterized by an increase in bicarbonate or excessive loss of metabolic acids?

Metabolic Alkalosis Signup and view all the answers

What happens to water balance when angiotensin II is produced?

Sodium and water reabsorption is enhanced. Signup and view all the answers

What pH level indicates metabolic acidosis?

Less than 22 mmol/L of bicarbonate Signup and view all the answers

Study Notes

Normal Electrolyte Values and Imbalances

Potassium (K+): Normal range 3.5-5.0 mmol/L
- Hyperkalemia: > 5.0 mmol/L causing muscle weakness, cramping, and cardiac arrhythmias
- Hypokalemia: < 3.5 mmol/L causing muscle weakness, fatigue, and heart dysrhythmias
Sodium (Na+): Normal range 135-145 mmol/L
- Hypernatremia: > 145 mmol/L causing thirst, confusion, muscle twitching, and increased BP
- Hyponatremia: < 135 mmol/L causing lethargy, seizures, and confusion due to cerebral edema
Chloride (Cl-): Normal range 98-106 mmol/L
- Hyperchloremia: > 106 mmol/L, usually linked to hypernatremia
- Hypochloremia: < 98 mmol/L, often linked to hyponatremia

Solution Osmolality

Isotonic: Solutions with the same osmolality as body cells, like 0.9% saline, used for fluid replacement without affecting fluid balance
Hypertonic: Solutions with higher osmolality than body cells, like 3% saline, draw water out of cells causing them to shrink
Hypotonic: Solutions with lower osmolality than body cells, like 0.45% saline, cause water to move into cells, potentially leading to cell swelling

Edema

Edema is the fluid accumulation in interstitial spaces, caused by:
- Increased capillary hydrostatic pressure (e.g., venous obstruction, heart failure)
- Loss of plasma proteins (e.g., kidney disease)
- Increased capillary permeability (e.g., inflammation)
- Lymphatic obstruction (e.g., tumors)

Intracellular Fluid (ICF) and Extracellular Fluid (ECF)

ICF: Fluid inside cells, comprising two-thirds of the body's total body water (TBW)
ECF: Fluid outside cells, including interstitial fluid, plasma, and other body fluids, comprising one-third of the TBW
TBW varies with age, gender, and body composition

Osmotic and Hydrostatic Pressure / Starling Forces

Osmotic Pressure: The force pulling water into an area of higher solute concentration
Hydrostatic Pressure: The force pushing water out of the capillaries into interstitial spaces
Starling Forces: Capillary hydrostatic pressure, plasma oncotic pressure, interstitial hydrostatic pressure, and interstitial oncotic pressure, controlling fluid movement between capillaries and tissues

Water Balance: Renin-Angiotensin System (RAAS) and Antidiuretic Hormone (ADH)

RAAS: Activated when blood pressure or sodium levels drop.
- Kidneys release renin, activating angiotensin I.
- Angiotensin I converts to angiotensin II, causing vasoconstriction and stimulating aldosterone release, increasing sodium and water reabsorption by the kidneys
ADH: Secreted when plasma osmolality increases, promoting water reabsorption by the kidneys, reducing urine output

Acid-Base Balance

Normal pH: 7.35-7.45
Acidosis: Systemic increase in H+ concentration or a loss of bicarbonate
- Respiratory Acidosis: Caused by hypoventilation (PaCO2 > 45 mmHg, pH < 7.35)
- Metabolic Acidosis: Caused by an increase in noncarbonic acids or loss of bicarbonate (HCO3 < 22 mmol/L, pH < 7.35)
Alkalosis: Systemic decrease in H+ concentration or an increase in bicarbonate
- Respiratory Alkalosis: Caused by hyperventilation (PaCO2 < 35 mmHg, pH > 7.45)
- Metabolic Alkalosis: Caused by an increase in bicarbonate or excessive loss of metabolic acids (HCO3 > 26 mmol/L, pH > 7.45)

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Description

This quiz covers the normal ranges for key electrolytes such as potassium, sodium, and chloride, along with their respective imbalances. Understand the causes and effects of hyperkalemia, hypokalemia, hypernatremia, and other conditions. Test your knowledge on electrolyte management and solution osmolality.