Bioquímica Clínica 03/05

Summary

This lesson focuses on electrolyte imbalances and their impact on the human body, particularly in relation to hydration and metabolism. It covers the balance of key electrolytes like sodium, potassium, and bicarbonate in maintaining cell function. Disturbances like hyponatremia, hypernatremia, and changes in blood pH (such as acidosis and alkalosis) are explained, emphasizing their effects on vital organs and overall health. The importance of proper fluid and electrolyte balance is highlighted, as well as the clinical significance of gasometric tests in diagnosing and managing these imbalances.

Takeaways

• 😀 Water makes up 60-70% of the human body, essential for the proper functioning of vital organs and metabolism.
• 😀 The body maintains a balance between intracellular (60%) and extracellular (30%) water compartments for optimal function.
• 😀 Disruptions in water balance, such as dehydration or overhydration, can lead to serious health complications.
• 😀 The blood volume, part of the extracellular compartment, is influenced by sodium concentration, which helps regulate water balance.
• 😀 Isotonic, hypotonic, and hypertonic states affect cell behavior: isotonic keeps balance, hypotonic causes cell swelling, and hypertonic leads to dehydration.
• 😀 Electrolytes like sodium, potassium, bicarbonate, and chloride are key in maintaining water and electrolyte balance in the body.
• 😀 Hyponatremia (low sodium) is diagnosed when serum sodium levels fall below 135 mmol/L, leading to potential neurological and cardiovascular issues.
• 😀 Hypernatremia (high sodium) occurs when serum sodium levels exceed 145 mmol/L and is often linked to conditions of water loss or dehydration.
• 😀 Hypokalemia (low potassium) is a serious electrolyte imbalance with dangerous effects, including muscle weakness and heart arrhythmias.
• 😀 Gasometries are used to assess acid-base balance in the body, measuring pH and the levels of carbon dioxide, bicarbonate, and hydrogen ions.
• 😀 Metabolic acidosis and alkalosis, along with respiratory acidosis and alkalosis, refer to disturbances in the blood's acid-base balance, with significant physiological consequences on cardiac, renal, and cellular function.

Q & A

What is the role of water in the human body?

Water constitutes 60-70% of the human body, with the majority found in the intracellular compartment. It is essential for the proper functioning of organs and metabolism, and dehydration can disrupt cellular and organ function.

What happens to a cell in an isotonic solution?

In an isotonic solution, the water content inside and outside the cell is balanced, meaning there is no net movement of water. The cell remains in a normal state, functioning properly.

What occurs to a cell in a hypotonic solution?

In a hypotonic solution, more water enters the cell than leaves it, causing the cell to swell. This can lead to hemolysis (rupture) if the swelling is severe.

What is a hypertonic solution and how does it affect cells?

In a hypertonic solution, water leaves the cell, causing the cell to shrink and become dehydrated. This dehydration impairs cellular function and can lead to cell death.

What is hyponatremia, and when is it considered severe?

Hyponatremia is a condition where the sodium concentration in the blood is too low, below 135 mmol/L. It is considered severe when the sodium level drops below 120 mmol/L, potentially leading to serious health complications.

How does hypernatremia affect the body?

Hypernatremia occurs when sodium levels exceed 145 mmol/L, often due to dehydration. This condition leads to hyperosmolarity, causing cells to lose water and leading to cell dysfunction.

What are the risks of hypokalemia and hyperkalemia?

Hypokalemia (low potassium) can cause muscle weakness, cramps, and arrhythmias, while hyperkalemia (high potassium) can be fatal, especially if potassium levels exceed 7.5 mmol/L, affecting the heart's electrical function.

What is the role of bicarbonate in acid-base balance?

Bicarbonate helps maintain the pH balance in the blood by neutralizing excess hydrogen ions. A decrease in bicarbonate leads to acidosis, while an increase leads to alkalosis.

What is the significance of a blood gas test in diagnosing acid-base imbalances?

A blood gas test measures the pH, CO2 levels, and bicarbonate concentrations in the blood, providing key information for diagnosing acid-base disturbances like metabolic acidosis, respiratory acidosis, and alkalosis.

What happens during metabolic acidosis?

Metabolic acidosis occurs when there is an excess of hydrogen ions or a loss of bicarbonate in the blood, leading to a decrease in blood pH. This condition can affect cardiac function and lead to complications like hyperkalemia and calcium mobilization.