What Are Kidneys?

If you were to list the most important organs in the human body, you would probably list your brain, your heart and your lungs. But did you know your kidneys are just as vital as these major organs? Every human needs a least one kidney to live.

Most people are born with two kidneys and if you’ve ever seen a kidney bean – yes, those beans you put in your nachos, then you already know what a kidney looks like. Each kidney is about 13 centimetres long and about 8 centimetres wide — around the size of a computer mouse, or the size of your clenched fist.

To find your kidneys, simply put your hands on your hips, then slide your hands up until you can feel your ribs. Now if you put your thumbs on your back, you will know where your kidneys are. You can’t feel them, but they are there.

What Do Kidneys Do?

Kidneys have a very important role to keep your body healthy. One of their main jobs is to filter waste out of your blood. But how does the waste get in your blood? Well, your blood delivers nutrients to your body. Chemical reactions in the cells of your body break down the nutrients. Some of the waste is the result of these chemical reactions while some of it is just stuff your body doesn’t need because it already has enough. The waste has to go somewhere; this is where the kidneys come in.

Through the renal artery, blood is carried into your kidney. Fun fact, anything in the body that is related to kidneys is called ‘renal’ which is why you will hear this word a lot. The average person has 1 to 1½ gallons of blood circulating through their body which the kidneys filter around 40 times a day! More than 1 million tiny filters inside the kidneys remove the waste. These filters, called nephrons (say: NEH-fronz), are so small you can only see them with a high-powered microscope.

How Is Pee Made?

The waste your kidneys remove mixes with water, which is also filtered out of your kidney. This turns into urine (pee). This urine then moves down a long, skinny tube called the ureter (say: yu-REE-ter) to your bladder, a sac that holds your pee.

When the bladder is about halfway full, your body releases signals to the brain to tell you to go to the bathroom. When you pee, the urine travels from your bladder, out of your body, through a tube called the urethra (say: yu-REE-thruh)

The kidneys, the bladder, and their tubes are called the urinary system. Here’s a list of all of the parts of the urinary system:

• the kidneys: filters that remove waste from your blood and make urine
• the ureters: tubes that carry urine from each kidney to your bladder
• the bladder: a sac that collects the urine
• the urethra: a tube that carries your urine from your bladder out of your body

What’s Homeostasis?

The kidneys not only filter pee, but they also control and balance the volume of fluids and minerals in your body. This balance in your body is called homeostasis (say: hoh-mee-oh-STAY-sus).

Fluids such as water play a big role in maintaining homeostasis (balance) in your body. And your kidneys play an important role in the way water travels through your body.

Water leaves your body in more ways than just peeing. For example, it leaves your body through your skin when you sweat, through your mouth when you breath and even when you poop.

When you’re thirsty, your brain is telling you to drink more fluids to keep your body balanced. If you don’t have enough fluids in your body, your brain tells your kidneys by sending them a hormone. This hormone tells the kidney to hold onto some of the fluids it usually filters out. This means when you drink plenty of fluids, your brain doesn’t need to send out this hormone meaning your kidney will let go of more fluids.

Have you ever gone to the bathroom and your pee was a darker colour than usual? This is a sign that you’re not drinking enough water! It can also mean you are sweating too much so there is not enough water travelling through your body to your kidneys. Remember, your pee is made up of water, as well as the waste that is filtered out of your blood so when you drink more water, your pee become lighter in colour!

So, make sure you drink plenty of water!

What Else Do Kidneys Do?

As you can see, kidney are very important organs that are constantly working. Not only do your kidneys filter your blood and balance fluid every second of every day, but they also constantly react to hormones the brain sends them. Kidneys can even make their own hormones. This includes hormones that tell your body to produce more red blood cells, another very important part of your health.

Now you know what kidneys are, what they do, why they are important and how to take care of them!