What are the functions of sodium in our body?

Hint: The electrolyte which helps to maintain water content and helps to maintain blood pressure, muscles and nerve system is known as sodium. So sodium is an important chemical element which is added in our daily routine life in particular amounts. ECF is the important body compartment which has some ions. The ions are $Na^+$, $Cl^-$ and $HCO^{3-}$. Sodium level is calculated by the PNR concept. It is called a real function curve or salt loading curve.

Complete answer:
Sodium is a chemical element. It is an electrolyte which helps to maintain the water balance in the human body. Muscles and nerve systems are properly maintained by sodium. Blood pressure is also maintained properly by sodium. The body fluids are maintained properly by using sodium as a small ingredient in food. Sodium is available in the blood and lymph fluid. The main duty of sodium is controlling blood volume in our blood, maintaining fluid levels in the body. Sodium maintains blood pressure by attracting the water and holding the water. It is also used for osmotic pressure that is passing the fluids to and from the cells. The PNR concept is graphically represented by renal sodium excretion at a function of arterial pressure. It is nearly related to one tablespoon of salt. The daily sodium intake must be $150$mmol. The sodium ion is absorbed by the body via two mechanisms one is by being permeable between the interstitial cell and other is by being membrane with glucose and amino acids. Nephron absorbs the sodium in three regions. They are PCT, TALH, and DCT. High levels of sodium may cause major problems in our body. It leads to heart failure, lung cancer, and kidney failure. Blood tests are done to measure the sodium level in the body.

Note:
The recommended value for sodium in the human body is $2300$ milligrams or less. The FDA recommended this value. Normal sodium concentration $135 - 145$ meq/l. Sodium level is increased in our body then it is called hypernatremia. The low level of sodium in our body is called hyponatremia. So the value of sodium will affect the human body whether it is low or high. So it is maintained properly otherwise it is injurious to health.