Your body needs to maintain a balance of fluid and electrolytes to work properly. Learn how electrolytes and fluids interact and discover things that influence their balance, such as kidney function, thirst, hormones, medications and hydration levels.

Fluid and Electrolytes

The ocean has always fascinated me because it’s filled with some of the most interesting living things on the planet. Under the water, you’ll find everything from colorful tropical fish to scary looking octopi to enormous whales. All of these creatures rely on the salty water of the sea to survive. Salt, or more specifically sodium, is an electrolyte, which is a mineral that has an electric charge. It’s found dissolved in bodies of water, like the ocean, and, believe it or not, you. That’s right! Sodium is just one of the electrolytes found in your body’s fluids.

Electrolytes help with many things, like transmitting nerve impulses and maintaining proper muscle actions. So, it’s important that levels of electrolytes don’t get too high or too low. Because electrolytes are dissolved in body fluids, your body’s fluid balance and electrolyte balance are closely intertwined. In this lesson, you’ll learn about mechanisms that influence the fluid and electrolyte balance in your body.

Fluid Balance

Like the ocean, you hold a lot of water. In fact, well over half of your body weight is due to the fluids inside of you. In order to maintain fluid and electrolyte balance, the amount of water coming into your body must equal the water you lose through things like sweating, breathing, and going to the bathroom. This balancing act is orchestrated by a few mechanisms, including thirst, or the desire to drink. If your water level starts to drop, your thirst is stimulated. If your body has too much water, thirst is turned off. Another mechanism that helps with the regulation of body fluid is the communication that takes place between your pituitary gland and your kidneys, which are the paired organs that excrete urine. Your pituitary gland is an endocrine gland found at the base of your brain that secretes antidiuretic hormone. If the fluid level inside of you gets too low, it jumps into action. Antidiuretic hormone, which is also known as ADH or vasopressin, carries an order to your kidneys telling them to stop excreting urine. The action of this hormone is easy to recall if you remember that the prefix ‘anti’ means opposed and the suffix ‘diuretic’ refers to urination. So, antidiuretic hormone is secreted to oppose urination.

Earlier, I mentioned that fluid and electrolyte balance in the body are closely intertwined. This is very true. In fact, electrolytes help your body maintain normal fluid levels. Body water moves from one area to another, based on the concentration of electrolytes. If an area of your body has a lot of electrolytes, particularly sodium, water goes there to bring the electrolyte concentration down. To recall this, I always think that water likes salt, so, water follows salt wherever it goes.

Electrolyte Balance

Sodium is not the only electrolyte found in your body. Some of the other important electrolytes include potassium, chloride, calcium, and magnesium. Your kidneys are important regulators of electrolytes. If your body has too many of any type of electrolyte, it can filter more of them out of the blood and excrete them. If your body is low on a certain electrolyte, your kidneys can return them to your blood. Because of the role your kidneys play in retaining or eliminating electrolytes in water, it’s easy to see that a kidney disorder could throw off your body’s balance. There are also medications, such as diuretics, that could interfere with your body’s fluid and electrolyte balance. We already learned that the term ‘diuretic’ refers to urination. Diuretics, therefore, are a type of medication that encourages urination. These drugs make you urinate more often, by forcing your kidneys to excrete higher than normal amounts of sodium. Because water loves salt, water follows the extra sodium out through your urine.

Electrolyte balance can also be thrown off if factors lead you to become dehydrated. In other words, if something happens that causes the loss of a large amount of water from your body. Many people think of dehydration in association with excessive sweating on a hot summer’s day. This is one of the possible factors, but there are others. For instance, if you’ve ever been really sick, then you’re already familiar with some of the more common factors that can lead to dehydration, such as continual vomiting or diarrhea.

Lesson Summary

Let’s review. In this lesson, we learned about a few mechanisms that help to maintain a proper fluid balance in your body, including thirst, or the desire to drink, and the communication that takes place between your pituitary gland and your kidneys. Your pituitary gland is an endocrine gland found at the base of your brain that secretes antidiuretic hormone. That hormone carries an order to your kidneys telling them to stop excreting urine. We also learned that electrolytes help your body maintain normal fluid levels. An electrolyte is a mineral that has an electric charge. Your kidneys are important regulators of electrolytes. Other factors that can effect fluid and electrolyte balance in your body include a kidney disorder, diuretics, and dehydration.