PLASMA ELECTROLYTES: FUNCTIONS, VALUES ​​AND ALTERATIONS - ANATOMY AND PHYSIOLOGY - 2025

The plasma electrolytes are a group of ions (electrically charged elements) that are found in blood and perform many tasks in the body. The balance of these electrolytes is essential for the normal functioning of the organs of the human body.

All humans need electrolytes to survive. Many processes of the body require the action of a small electrical charge, which is provided by electrolytes. These ions interact with each other and with the cells that make up the various tissues, nerves and muscles.

An electrolyte imbalance occurs when the plasma levels of any electrolyte are too high or too low, which generates a series of alterations in the body that are reflected as symptoms or signs of some disease.

Features

As previously mentioned, serum electrolytes fulfill a huge number of physiological tasks in the body. The most important electrolytes with some of their respective tasks are listed below:

Sodium (Na +)

Sodium is the most abundant cation (positively charged ion) outside the cell. One of its most important functions is the regulation of the amount of water in the body.

A maxim of medicine is that water follows sodium wherever it goes, whether it is inside or outside cells or blood vessels.

Many organic processes in the brain, central nervous system, and muscles require electrical signals to perform. The constant entry and exit of sodium from the cells into the plasma and vice versa generates that very important electrical signal.

The transmission of cardiac impulses for normal heart function is also mediated by sodium. Heartbeat is highly dependent on serum sodium levels being within normal ranges.

Potassium (K +)

Potassium is the most abundant intracellular cation. It has an inverse relationship with sodium, through the sodium-potassium pump in the cell membrane, so it performs vital tasks in controlling the heartbeat and in the functioning of the muscles.

It has a role in the osmotic balance and in the fluid balance between the intracellular and the extracellular space. As it is the positive ion with the greatest presence within the cell, its exchange with sodium is essential to maintain the acid-base balance and the pH of the body.

Chlorine (Cl-)

Chlorine is the largest anion (negatively charged ion) in the extracellular space. Like its two predecessors, it has a significant role in maintaining balanced fluids within the body. It is closely linked with sodium, so its levels rise or fall depending on the behavior of the aforementioned sodium.

Helps in the work and maintenance of the joints and tendons. It also participates in the acid-base balance and in the regulation of body fluids.

It is part of the hydrochloric acid that intervenes in the digestion of food and its influence on the proper functioning of the liver has been studied.

Bicarbonate (HCO3-)

The bicarbonate anion is the first compound ion with significant participation in the body. By its formula it is understood that it has hydrogen, carbon and oxygen in its composition, but it tends to join with other elements to fulfill its various tasks.

The main function of bicarbonate is to act as a buffer or buffer substance. These mixtures help maintain the acid-base balance in the body by regulating pH values. In its form of sodium bicarbonate, it acts by neutralizing gastric acid and serves as a transport for the elimination of carbon dioxide.

Effects of bicarbonate on vascular musculature have been described to increase or decrease the caliber of vessels and blood flow. Likewise, the kidneys and lungs are very sensitive to serum levels of bicarbonate and some of their functions depend on their levels in the blood.

Calcium (Ca +) and phosphorus (P-)

Calcium is the most abundant mineral in the body, with phosphorus being the second. Their presence in bones and teeth gives them that particular condition, but their functions in the acid-base balance are not so important. However, they fulfill many vital tasks in the body.

Among the metabolic tasks of calcium and phosphorus we have the transmembrane transport of other ions and the release of neurotransmitters.

Calcium is necessary for muscle contraction and heartbeat, as well as for blood clotting. Phosphorus is part of ATP, the main energy provider in the body.

Magnesium (Mg +)

Magnesium is the second most important intracellular cation after potassium. Its most recognized function is acting as a coenzyme in many organic chemical reactions.

In addition, it works by stabilizing DNA and RNA chains, forming glycogen, absorbing calcium and vitamin C, and helping muscles function.

Normal values

The plasma levels of the different electrolytes can vary depending on the laboratory that performs them or the reagents used to measure it. The most recognized values ​​are listed below, expressed in the most frequently used units:

Sodium

135 - 145 mEq / L

Potassium

3.5 - 5.3 mEq / L

Chlorine

98 - 107 mEq / L

Calcium

4.5 - 5.5 mEq / L

Magnesium

1.4 - 2.5 mEq / L

Match

2.5 - 4.5 mg / dL

Baking soda

22 - 30 mmol / L

These values ​​are considered normal in healthy adults. The ranges can be modified in children, pregnant women and older adults.

Alterations

Abnormal plasma levels of serum electrolytes have many consequences in the body. The most frequent general symptoms due to these alterations are:

- Cardiac arrhythmias.

- Fatigue.

- Seizures.

- Nausea and vomiting.

- Diarrhea or constipation.

- Muscle weakness and cramps.

- Irritability.

- Confusion.

- Headaches.

Electrolyte imbalances are named by adding the prefixes "hypo" and "hyper," depending on whether the values ​​are lower or higher than normal. Thus, when calcium levels are altered they are indicated as hypocalcemia or hypercalcemia or if it is magnesium it would be hypomagnesemia or hypermagnesemia.

In the case of sodium, the correct terms are hyponatremia and hypernatremia, since in Latin it is known as natrium. In the case of potassium, they must be hypokalemia and hyperkalemia due to its Latin origin kalium.

References

1. NIH: US National Library of Medicine (2015). Electrolytes. Recovered from: medlineplus.gov
2. Felman, Adam (2017). Everything you need to know about electrolytes. Recovered from: medicalnewstoday.com
3. Holland, Kimberly (2017). All About Electrolyte Disorders. Recovered from: healthline.com
4. Terry, J (1994). The Major Electrolytes: sodium, potassium and chloride. Journal of Intravenous Nursery, 17 (5), 240-247.
5. Wedro, Benjamin (2017). Electrolytes. Recovered from: emedicinehealth.com
6. Salzman, Andrea; Lampert, Lynda and Edwards, Tracy (2018). Electrolyte Imbalance + Normal Ranges and Disturbances for Common Electrolytes. Recovered from: ausmed.com