Urology Cancers: All about bladder, kidney, prostate, and Cancers

The kidneys are best known for filtering blood and making urine, but they also serve as important hormone-producing organs. These hormones are chemical messengers that help control essential body functions beyond the urinary system. One of the most important hormones made by the kidneys is erythropoietin (often shortened to EPO). This hormone tells your bone marrow to produce red blood cells. When oxygen levels in your blood drop—such as at high altitude or due to illness—your kidneys release more erythropoietin to help increase the number of red blood cells and improve oxygen delivery throughout the body. Another key hormone is renin, which helps regulate blood pressure. When blood pressure drops too low, the kidneys release renin into the bloodstream. This triggers a chain reaction called the renin-angiotensin-aldosterone system (RAAS). It causes blood vessels to narrow and helps the body retain salt and water, both of which raise blood pressure to a safer level. The kidneys are also...

Most people know that the kidneys filter blood and make urine, but not everyone realizes they also play a vital role in keeping bones healthy. The kidneys help maintain bone strength by managing key minerals and activating vitamin D—both essential for strong, healthy bones. One of the most important ways the kidneys support bone health is by activating vitamin D. The form of vitamin D you get from food or sunlight is inactive. Your kidneys convert it into its active form, known as calcitriol, which helps your body absorb calcium from the diet. Without enough active vitamin D, your body cannot absorb the calcium it needs, no matter how much you consume. The kidneys also help regulate the levels of calcium and phosphorus in the blood. These minerals are crucial for building and maintaining bone tissue. When there is too much phosphorus or too little calcium, your body may take calcium from your bones to make up the difference, which can weaken them over time. To prevent this, the kidneys...

Your kidneys are constantly working to keep the right amount of water and salt in your body. Whether you are sweating on a hot day, drinking lots of fluids, or not drinking enough water, your kidneys adjust automatically to maintain balance. This ability to respond to changing fluid levels is essential for your health and survival. When you are dehydrated, the body needs to hold on to water. In response, the brain releases a hormone called antidiuretic hormone (ADH), which tells the kidneys to conserve water. The kidneys then produce less urine, and the urine becomes darker and more concentrated. This helps prevent further water loss and keeps your blood volume and pressure stable. In contrast, when you take in too much fluid, the kidneys increase urine production to get rid of the excess. The urine becomes clearer and more diluted. This prevents the buildup of water and helps avoid swelling or dangerously low sodium levels in the blood. Salt levels also play a role. When you eat a hig...

Your kidneys do much more than make urine. They filter your blood, balance your fluids, control blood pressure, and support bone and red blood cell health. But how exactly do they do all this? This page is your one-stop resource for understanding how the kidneys work—one question at a time. Whether you are curious about how much urine is normal, what kidneys remove from the blood, or what happens with only one kidney, you will find simple, science-backed answers here. Each topic below links to a short article that explains one key question in plain language. These articles are designed for anyone to understand—no medical background needed. As new articles are published, they will be added to the list below. Bookmark this page and check back often for the latest updates. What do the kidneys do in the human body? How do the kidneys filter blood? Where are the kidneys located in the body? Can you live a normal life with one kidney? How much urine do healthy kidneys produce in a day? What ...

Your body is made up of about 60 percent water, and keeping that fluid in balance is vital for every cell, tissue, and organ. The kidneys play a central role in this process. They constantly monitor and adjust the amount of fluid in your body by controlling how much water and salt are excreted in the urine. When you drink more water than your body needs, your kidneys respond by producing more urine to get rid of the excess. When you are dehydrated, they conserve water by concentrating the urine and producing less of it. This automatic adjustment helps maintain the right fluid levels in your blood and tissues. In addition to water, your kidneys also regulate electrolytes—minerals like sodium, potassium, and calcium—that are dissolved in body fluids. These electrolytes help control everything from nerve signals to muscle contractions. Too much or too little of any of them can disrupt important body functions. The kidneys carefully balance these levels by increasing or decreasing how much...

Inside each of your kidneys are tiny working units called nephrons—and each kidney has about one million of them. These microscopic structures are the key players in filtering blood, removing waste, and producing urine. Each nephron has two main parts: the glomerulus, which is a small group of blood vessels that acts like a filter, and the tubule, which processes the filtered fluid. As blood passes through the glomerulus, waste products, extra water, and small molecules like salts are filtered out. The fluid then moves through the tubule, where the body reabsorbs what it still needs and sends the rest out as urine. Together, the nephrons in both kidneys filter about 180 liters (48 gallons) of blood per day. They adjust what to keep and what to remove based on your body’s needs at any given moment. This constant adjustment helps maintain the right balance of fluids, salts, and other important substances in your blood. Interestingly, not all nephrons are active at the same time. Some sta...

GFR stands for glomerular filtration rate, and it is one of the most important numbers used to assess how well your kidneys are working. It tells you how much blood your kidneys filter each minute, helping detect early signs of kidney function decline. In a healthy adult, the GFR is typically around 90 to 120 milliliters per minute (mL/min). This means the kidneys are filtering that amount of blood every minute. If your GFR is lower than normal, it may suggest that your kidneys are not removing waste from the blood as efficiently as they should. GFR is not measured directly but is estimated using a blood test, usually based on your creatinine level, along with other factors like age, sex, and body size. The result is called estimated GFR or eGFR, and it is a routine part of most kidney function tests. Here is what eGFR can indicate: A value above 90 is usually considered normal (if no other signs of kidney issues are present). A value between 60 and 89 may still be normal but should be...