Take Time To Appreciate Your Kidneys
Since March is National Kidney Month, take a few moments to learn, and maybe appreciate, more about your kidneys:
WHAT ARE KIDNEYS?
Kidneys are two of the most important organs in your body. They filter your blood and help rid your body of waste products. Each kidney is about the size of a mobile phone. They have a unique shape - kidney beans are so named for their similar shape. Your kidneys are located just under your back ribs, but you cannot feel them with your hands. Inside each kidney there are about a million nephrons, which are tiny filters that catch what your body doesn't need to send it out as waste.
WHAT DO KIDNEYS DO?
1) Kidneys get rid of waste products carried in the blood.
As part of your body's waste disposal system, kidneys seek out the minerals, vitamins and other nutrients you get from food and send off into urine anything that is not needed. The urine they make is sent to the bladder through tubes called the ureters, and when your bladder feels full enough the brain tells you it's time to rid yourself of the urine.
2) Kidneys balance the volume of fluid in the body.
The blood volume in an adult body is approximately 7 percent of body weight. An average adult with a weight of 150 to 180 pounds will contain approximately 1.2 - 1.5 gallons of blood (children have smaller amounts, depending on their size). All of this gets filtered through the kidneys many times a day. When fluid volume in your body goes down, perhaps as a result of sweating a lot of fluid through your skin or maybe from not drinking enough water, your kidneys will not produce as much urine until the amount of fluid in your body goes up. Kidneys help maintain the proper levels of electrolytes (such as sodium and potassium), and the amount of electrolytes in the body influences the amount of fluid in the body. When electrolyte levels are high, the body retains more water, which in turn increases the volume of the blood. (See #3 below. More blood volume results in higher blood pressure. So the kidneys maintain blood pressure by indirectly controlling the amount of blood in the body.)
3) Kidneys can affect your blood pressure.
Kidneys make a hormone which can constrict the arteries of the body, causing your blood pressure to rise whenever a higher pressure is needed to ensure blood reaches all parts of your body. While filtering wastes and extra fluids from blood, the kidneys use a lot of blood vessels. Over time, uncontrolled high blood pressure can cause arteries around the kidneys to narrow, weaken, or harden, and those damaged arteries may not be able to deliver enough blood to kidney tissues. Your kidneys monitor blood pressure by measuring the amount of blood flow they receive through special cells in the arteries that feed into the kidneys. So, when blood flow to the kidney is reduced, your body can interpret this as low blood pressure (even when blood pressure throughout the body is actually normal or even elevated), triggering excretion of a hormone called renin to act to elevate blood pressure. Work with your medical team to carefully monitor and best understand how to manage your blood pressure.
4) Kidneys produce active vitamin D.
Healthy kidneys are rich with vitamin D receptors and play a major role in turning vitamin D into its active form. Vitamin D helps your body absorb calcium, which is needed for making strong bones and teeth, from dairy products and other foods you eat.
5) Kidneys help with red blood cells.
Red blood cells are made inside your bones, in the bone marrow. A hormone made by the kidneys tells your body when to make more red blood cells. (Hemoglobin is the protein inside red blood cells that carries oxygen around the body. Red blood cells also remove carbon dioxide from your body, transporting it to the lungs for you to exhale.) Healthy kidneys also stop red blood cells from going into your urine. So, if you ever see blood in your urine, be sure to talk with your physician.