The Importance of Acid-Base Balance in Maintaining Homeostasis
Written by Draga Neskovic, BA Philosophy, Adult Education. Updated on March 12, 2023.
Our bodies use a variety of physiological adaptations to preserve homeostasis.
Body temperature control is probably the best-known example of homeostasis. Natural body temperature is around 98.6 °F (37 °C).
But there are a number of other processes our bodies conduct daily to help us maintain homeostasis and stay healthy and alive.
One of them is the acid-base balance. It is far less known but crucial to human survival.
Read along to discover phenomenons such as acid-base balance, acidity, and alkalinity, the mechanisms our bodies use to control them, acid-base disorders, and much more.
What Is Acid-Base Balance?
Acid-base balance describes the blood’s balance between acidity and alkalinity.
Acidity and alkalinity are determined by using a pH scale.
The pH scale spans from 0 (which means strongly acidic) to 14 (strongly alkaline, also known as basic). The value of 7, placed between the two extremes, is neutral.
Low pH values result from increased acidity, while higher pH indicates higher alkaline content.
The normal pH of our bodies has very narrow limits – between 7.35 and 7.45. Interestingly, the pH of our blood is around 7.40 (somewhat alkaline) and not 7 (neutral).
The reason is that the 7.40 pH is appropriate for a variety of biological activities, and the oxygenation of the blood is one of the most crucial.
Even a small alteration from the typical range might severely affect our organs and overall health. If the pH reaches above 7.8 or below 6.8, it usually leads to death.
Our body regulates the acid-base balance in the blood by using two main organs – lungs and kidneys.
Here is a simplified version of how our lungs help us maintain homeostasis repeatedly.
Carbon dioxide is an acidic byproduct of oxygen processing and is continuously created by the cells. From the cells, it moves through the blood to our lungs.
Finally, the lungs release it from the body. While it is still in the blood, the pH levels of the blood drop (which means acidity rises).
Since human bodies are complex, holistic entities, the lungs do not act alone. The brain adjusts the amount of carbon dioxide the lungs free by controlling the depth and rate of breathing.
Unlike the lungs (with the brain’s help), which can control and change the blood pH almost in seconds, the kidneys require more time to carry out the same process – up to several days.
By discharging extra acids or bases, the kidneys can modify the pH of the blood. They can adjust the amount of acid and base they eject, but, as mentioned above, it takes more time.
In the next section, we will explain the types of acid-base disorders.
Acid-Base Disorders
When the acid and base are not in balance, some issues appear.
When the blood contains high acid levels (or is low in base), the pH is lower than 7.35. This abnormality is called acidosis.
On the other hand, when there is too much base (or not enough acid) in the blood, the pH value will rise above 7.45. This is called alkalosis.
As mentioned before, the lungs and kidneys are key to maintaining acid-base balance. That is why acidosis and alkalosis can be both respiratory (lungs) and metabolic (kidneys).
Both acidosis and alkalosis are usually just symptoms of other, more severe health conditions and not actual diseases.
On the bright side, when there isn’t a dangerous illness behind the changes in the blood pH, our bodies work in a way that will lead the pH back to its regular value.
While metabolic systems make up for respiratory abnormalities, the respiratory system compensates for metabolic issues. This way, these mechanisms work as allies to adjust the blood’s acid-base balance.
The body’s capacity to adjust fails if the blood pH drastically changes. This calls for an urgent need to identify and treat the root cause of the acid-base disruption.
Respiratory Acidosis
Respiratory acidosis occurs when the lungs can not eliminate extra carbon dioxide, making the blood more acidic than it should be.
Some of the symptoms include lethargy, breathing difficulties, and confusion.
There are numerous reasons behind this acidosis, such as chronic lung problems, injuries or alterations to the chest, excessive sedative use, obesity, etc.
In order to lower the risk of respiratory acidosis, avoid smoking, try to keep fit by eating healthy and engaging in physical activity, and do not take sedatives unless they were prescribed by your doctor.
Metabolic Acidosis
Your body either produces too much acid, or your kidneys can not effectively eliminate it, resulting in metabolic acidosis.
Symptoms are the same as those of respiratory acidosis.
There are three varieties of metabolic acidosis:
- Diabetic acidosis – caused by unregulated type 1 diabetes
- Hyperchloremic acidosis – can occur after, for example, diarrhea due to excessive sodium bicarbonate loss
- Lactic acidosis – appears when lactic acid builds up in excess. It can be caused by a wide variety of reasons, including hypoglycemia (low blood sugar), kidney and liver issues, certain medications, and alcohol…
Respiratory Alkalosis
Respiratory alkalosis occurs when the blood has low levels of carbon dioxide.
Some causes include hyperventilation during panic attacks, pneumonia, pulmonary embolism, etc.
The symptoms are nausea, vomiting, lightheadedness, muscle spasms, and shaking hands…
Metabolic Alkalosis
Metabolic alkalosis is the medical term for when your blood contains too much bicarbonate.
It can be split into two primary groups that aid in determining the cause: those that are chloride responsive and those that are not.
The symptoms are the same as those of respiratory alkalosis.
One of the common causes of metabolic alkalosis is prolonged vomiting.
Conclusion
Acid-base balance describes the blood’s balance between acidity and alkalinity.
The normal pH value of our blood is around 7.40.
The respiratory (lungs) and renal (kidneys) system aid in the maintenance of the acid-base balance.
The deviations from the typical acid-base balance include acidosis (respiratory and metabolic) and alkalosis (respiratory and metabolic).
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