The human body maintains a delicate internal balance, including the regulation of acidity and alkalinity, known as pH levels. Significant deviations from normal pH can lead to serious conditions like acidosis or alkalosis.
Understanding pH and Homeostasis
pH measures how acidic or alkaline a solution is, ranging from 0 (acidic) to 14 (alkaline), with 7 being neutral. Blood pH in the human body is tightly regulated between 7.35 and 7.45. Even small deviations disrupt cellular processes.
Maintaining stable pH is crucial because enzymes and proteins function properly only within a specific pH environment. If pH is too high or low, these molecules lose effectiveness, impairing bodily functions. The body’s ability to maintain stable internal conditions is called homeostasis.
Acidosis: Causes and Effects
Acidosis occurs when blood pH falls below 7.35, becoming too acidic. This imbalance results from excess acid production or the body’s inability to remove acids. Causes include severe diarrhea, which leads to bicarbonate loss, and kidney failure, where kidneys cannot excrete excess acids.
Lung diseases like emphysema or chronic bronchitis can also cause acidosis by impairing carbon dioxide removal, leading to carbonic acid buildup. Symptoms of acidosis include fatigue, nausea, vomiting, and deep, rapid breathing (Kussmaul breathing). Confusion and drowsiness can also occur.
Alkalosis: Causes and Effects
Alkalosis occurs when blood pH rises above 7.45, becoming too alkaline. This results from excessive acid loss or bicarbonate accumulation. Common causes include hyperventilation, which expels too much carbon dioxide, reducing carbonic acid and increasing alkalinity.
Severe vomiting can also induce alkalosis by causing significant stomach acid loss. Overuse of certain diuretics, which promote acid and electrolyte excretion, can contribute. Symptoms of alkalosis include muscle twitching, numbness or tingling in hands and feet, lightheadedness, and muscle cramps or spasms.
How the Body Maintains pH Balance
The body regulates pH using several mechanisms. Chemical buffer systems, like the bicarbonate-carbonic acid buffer, act rapidly. They absorb excess hydrogen ions (acids) or release them when alkalinity increases, minimizing pH changes.
The respiratory system, primarily the lungs, regulates pH by controlling blood carbon dioxide levels. Carbon dioxide forms carbonic acid in blood. If blood becomes too acidic, breathing increases to expel more carbon dioxide, reducing acid. If blood becomes too alkaline, breathing slows to retain carbon dioxide, increasing acidity.
The renal system (kidneys) provides a slower, more powerful pH balance mechanism. Kidneys regulate pH by adjusting hydrogen ion excretion and bicarbonate reabsorption or excretion. They excrete excess acid or conserve bicarbonate when acidic, and excrete bicarbonate when alkaline. These systems work cooperatively to maintain stable pH.
Distinguishing Types and Symptoms
Acidosis and alkalosis are categorized into two types: respiratory and metabolic. Respiratory types result from lung issues managing carbon dioxide. Metabolic types stem from problems with bicarbonate levels or other acid/base production and excretion.
Respiratory Acidosis
Respiratory acidosis occurs when lungs cannot adequately remove carbon dioxide, increasing carbonic acid. Causes include severe asthma or opioid overdose. A person might exhibit shallow breathing and confusion.
Respiratory Alkalosis
Respiratory alkalosis results from hyperventilation, expelling too much carbon dioxide. This is often triggered by anxiety or high altitudes. Symptoms can include lightheadedness and tingling.
Metabolic Acidosis
Metabolic acidosis results from non-carbonic acid accumulation or bicarbonate loss. Examples include uncontrolled diabetes (ketoacidosis) or kidney failure. Individuals often compensate by increasing breathing rate to expel more carbon dioxide, leading to deep, rapid breaths (Kussmaul breathing).
Metabolic Alkalosis
Metabolic alkalosis is caused by excessive stomach acid loss from prolonged vomiting or too much bicarbonate ingestion. Symptoms may include muscle weakness and cramps.
Distinguishing between these types often requires specific blood tests, as symptoms can sometimes overlap.