ACIDS AND BASES IN THE HUMAN BODY
In case you did not get a chance to study the following concepts during your Biology class, here
are just some of the very many important ACIDS and BASES vital to human health and
biochemistry. Needless to say, acid-base chemistry is much bigger and more significant than
laboratory experiments and titrations! This handout will also introduce you to conditions
associated with pH problems in blood through the presentation of ACIDOSIS and ALKALOSIS.
Here are some of the places that acids and bases can be found in the human body:
1. DNA is a complex NUCLEIC ACID found in cells that contains four unique nitrogen-based
BASES: adenine, cytosine, guanine and thymine. Differing combinations of these four bases
determine the genetic characteristics of all human life.
2. AMINO ACIDS are the building blocks of proteins! The majority of amino acids consist of both
a carboxylic acid (-COOH) and an amino (-NH2) functional group attached to the same tetrahedral
3. LACTIC ACID is an acid produced when sugars are processed by the body. The production of
too much lactic acid can cause serious health issues and even death.
4. Vitamin C has the chemical name ASCORBIC ACID and Aspirin and other pain relief
remedies are also organic acids. Here is the chemical structure of Aspirin:
5. BLOOD is naturally buffered to a pH of 7.35 – 7.45 in healthy humans. While our bodies
naturally work to keep a healthy acid-base balance, problems can arise when acidic or basic
compounds are too concentrated or not present in high enough concentrations. The blood's
acid-base balance is precisely controlled, because even a minor deviation from the normal range
can severely affect many organs. The body uses different mechanisms to control the blood's
acid-base balance such as the release of CO2 from the lungs, adjusted kidney function for
excretion of substances and controlled buffering of blood via concentrations of the bicarbonate
6. Acidosis and alkalosis are the two abnormalities of acid-base balance. In acidosis, the blood
has too much acid (or too little base), resulting in a decrease in blood pH. In alkalosis, the blood
has too much base (or too little acid), resulting in an increase in blood pH. Acidosis and alkalosis
are not diseases, but rather are conditions that result for a variety of reasons.
Acidosis is excessive blood acidity caused by an overabundance of acid in the blood or a loss of
bicarbonate from the blood (metabolic acidosis), or by a buildup of carbon dioxide in the blood
that results from poor lung function or slow breathing (respiratory alkalosis).
If an increase in acid overwhelms the body's pH buffering systems, the blood will become acidic.
As the blood pH drops, the parts of the brain that regulates breathing are stimulated to produce
faster and deeper breathing, which increases the amount of carbon dioxide exhaled.
The kidneys also try to compensate by excreting more acid in the urine. However, both
mechanisms can be overwhelmed if the body continues to produce too much acid, leading to
severe acidosis and eventually coma.
Metabolic acidosis develops when the amount of acid in the body is increased through ingestion
of a substance that is, or can be metabolized to, an acid—such as wood alcohol (methanol),
antifreeze (ethylene glycol), or large doses of aspirin (acetylsalicylic acid). Other problems occur
when the kidneys are not functioning normally and are therefore not able to excrete sufficient
amounts of acid in the urine. In addition, a person can develop respiratory acidosis if overly
sedated from opioids (narcotics) and strong sleeping medications that slow respiration.
A person with mild metabolic acidosis may have no symptoms but usually experiences nausea,
vomiting, and fatigue. Breathing becomes deeper and slightly faster (as the body tries to correct
the acidosis by expelling more carbon dioxide). As the acidosis worsens, the person begins to
feel extremely weak and drowsy and may feel confused and increasingly nauseated. Eventually,
blood pressure can fall, leading to shock, coma, and death.