Acid Base Balance

What is pH?

A scale used to specify the acidity or alkalinity of an aqueous solution.

Neutral pH value

7.0, where H⁺ and OH⁻ concentrations are equal.

Acidic Solution

A solution with pH less than 7.0, indicating higher H⁺ concentration.

Basic (Alkaline) Solution

A solution with pH greater than 7.0, indicating higher OH⁻ concentration.

Normal pH Range in Blood

Typically between 7.35 to 7.45.

Arterial Blood pH

Approximately 7.45.

Venous Blood pH

Slightly lower, about 7.35.

What are Chemical Buffers?

Substances that neutralize small amounts of added acid or base, preventing sharp pH changes.

Example of a chemical buffer in blood

Bicarbonate buffers.

Respiratory Mechanism in pH control

Involves the removal of CO₂ from blood, which is a component of carbonic acid.

Role of breathing rate in pH balance

Increased respiration expels more CO₂, reducing acidity; decreased respiration retains CO₂, increasing acidity.

Kidney function in pH regulation

Kidneys excrete or retain acids and bases, adjusting the pH over hours to days.

Respiratory Acidosis

Results from conditions causing CO₂ retention, such as hypoventilation.

Metabolic Acidosis

Due to a bicarbonate deficit, often from chronic diarrhea or renal failure.

Respiratory Alkalosis

Occurs from excessive CO₂ loss, often due to hyperventilation.

Metabolic Alkalosis

Results from an excess of bicarbonate, commonly due to severe vomiting or overuse of diuretics.

Metabolic Acidosis Compensation

The body adjusts by increasing breathing to expel more CO₂.

Uncompensated vs. Compensated States in pH balance

In uncompensated, the ratio of bicarbonate to carbonic acid is disturbed; in compensated, the ratio remains constant at 20:1.