What functions do the electrolytes do in the body (Part 1.) ?😤

Electrolytes have the ability to maintain the osmotic pressure of body fluids the normal distribution of body fluids. There are composed of various anions and cations. Potassium, sodium, and chlorine are the three important electrolytes that are most relevant to the diseases and are most closely connected to the patient's life. Firstly, let's talk about potassium and the others will talk in the next two issue.

Potassium

Potassium is the most important cation distributed in the intracellular fluid. It has important physiological functions in maintaining the osmotic pressure of the intracellular fluid, acid-base balance, and maintaining the irritability of muscles and nerves.

1. Normal blood K⁺ concentration

The normal concentration of serum  K⁺  is about 3.5-5.5 mmol/L, the plasma K⁺ is about 0.5 mmol/L lower than the serum K⁺, because when the blood coagulates, K⁺ in platelets and other blood cells will release a few number to the serum.

2. Hyperkalemia and its causes

    a.) The cells are dismantled and potassium ions are forced to flow out to the external fluid. 

The K⁺ concentration of the intracellular fluid is 150.0 mmol/L, which is about 40 times the serum K⁺ concentration. When tissue cells are destroyed (such as    large-area burns, crush injuries), the K⁺ ions in the cells will be flow out to the serum, it result the increasing in blood K⁺. If the upper limit (5.5 mmol/L) is exceeded, it is hyperkalemia. It can lead to heart block, circulatory failure, cardiac arrest in diastole and finally die. 

There are some reasons lead to hemolysis. It can cause false increasing in blood K⁺ which is quite common. Therefore, when the samples with elevated K⁺, it is necessary to check whether the patient's sample is hemolyzed.

    b.) Potassium ions from the outside

Too much K⁺ input from the outside can also cause hyperkalemia, such as the input of a large amount of potassium solution or a large amount of stored blood.

    c.) In acidosis, potassium ions are used to exchange protons

Based on the acid-base balance,  in acidosis, there are many pumps on the cell membrane that can pump a H⁺ of the external fluid into the cell, and then pump a K⁺ out in addition to the regulation of lungs and kidneys. Therefore, patients with acidosis are often accompanied by hyperkalemia. Similarly, when patients have hyperkalemia, there will be a reverse operation, K⁺ is pumped back, and H⁺ is pumped out, and acidosis occurs. Interestingly, hyperkalemia not only leads to metabolic acidosis, but also abnormal alkaline urine.

3. Hypokalemia and its causes

Hypokalemia is also very common in clinical. In hypokalemia, patients may have mental abnormalities, increased heart rate, heart failure, and cardiac arrest in systole. The main causes of hypokalemia are insufficient intake, excessive loss, and potassium from outside the cell into the cell.

Glucose and insulin can drive potassium into the cell. When too much glucose with insulin is input, insulin promotes glucose to enter the cell then synthesize glycogen, it also brings potassium in.

OH^- also has this ability. In alkalosis, H⁺ is needed to neutralize, it pump H⁺ out of the cell and K⁺ back to the cell. Alkalosis is accompanied by hypokalemia, which can also lead to metabolic alkalosis and abnormal aciduria.