acid-base

Acid-Base Balance — The Big Picture

The body constantly produces acid as a byproduct of normal metabolism (CO2 from cellular respiration, ketones, lactic acid)

Acid-Base Balance — The Big Picture

It must keep the blood's hydrogen ion (H+) concentration — its pH — within a razor-thin normal range

Acid-Base Balance — The Big Picture

Even small pH shifts disrupt enzymes, oxygen transport, and nerve/muscle function

Acid-Base Balance — The Big Picture

Two organ systems do the correcting: the LUNGS (fast — adjust CO2 by changing the rate/depth of breathing) and the KIDNEYS (slow — adjust bicarbonate, HCO3-)

Acid-Base Balance — The Big Picture

Every acid-base disorder is one of these two systems pushing pH in one direction, with the other system trying to compensate

Acid-Base Balance — The Big Picture

If you know which system caused the problem (respiratory

Normal Blood pH

7.35 – 7.45

Normal Blood pH

< 7.35 → Acidosis (too much acid / too little base)

Normal Blood pH

7.45 → Alkalosis (too much base / too little acid)

Normal Blood pH

A stable pH is necessary for proper enzyme function

Normal Blood pH

A stable pH is necessary for oxygen transport (hemoglobin binding)

Normal Blood pH

A stable pH is necessary for nerve and muscle activity

Normal Blood pH

A stable pH is necessary for electrolyte balance

Normal Blood pH

Even a small deviation from normal can cause serious physiologic problems or death

Sources of Acids & Bases — Cell metabolism

Example: CO2 → H2CO3 (carbonic acid)

Sources of Acids & Bases — Cell metabolism

Effect on pH: Lowers pH (acidic)

Sources of Acids & Bases — Fat breakdown

Example: Ketone bodies

Sources of Acids & Bases — Fat breakdown

Effect on pH: Acidic

Sources of Acids & Bases — Anaerobic metabolism

Example: Lactic acid

Sources of Acids & Bases — Anaerobic metabolism

Effect on pH: Acidic

Sources of Acids & Bases — Protein metabolism

Example: Sulfuric, phosphoric acids

Sources of Acids & Bases — Protein metabolism

Effect on pH: Acidic

Sources of Acids & Bases — Bicarbonate (HCO3-)

Example: Produced by metabolism or ingested

Sources of Acids & Bases — Bicarbonate (HCO3-)

Effect on pH: Raises pH (basic)