Peritubular capillaries are tiny blood vessels in your kidneys. They filter waste from your blood so the waste can leave your body through urine (pee). Peritubular capillaries also reabsorb nutrients your body needs to work properly, such as minerals. You have millions of these capillaries inside your kidneys’ nephrons (filtering units).
Peritubular capillaries are tiny blood vessels in your kidneys. They deliver wastes to be secreted into urine (pee). They also reabsorb nutrients your body needs. Peritubular capillaries play an essential role in your urinary system.
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Peritubular capillaries help your urinary system get rid of waste. They move waste and excess water through your kidney’s nephrons (filtering units). The waste travels into your bladder and leaves your body through urine (pee).
Peritubular capillaries also reabsorb substances your body needs to work properly, such as amino acids, minerals and glucose (sugar in your blood). They supply blood and oxygen to the cells in a system of tubes in your kidneys as well.
Each one of your kidneys contains about one million nephrons (filtering units). The nephrons include a glomerulus (the filter), and a system of different types of tubes and proximal convoluted tabule (PTC) surround them.
Peritubular capillaries are so small that you can’t see them with the naked eye. You need a microscope to see them. They're a type of blood vessel called fenestrated capillaries. This means that each capillary has tiny pores (openings).
The pores make it easier for blood, fluids and substances (such as minerals) to move back and forth between the capillaries and the tissues surrounding them. Each pore has a membrane that opens and closes, allowing larger molecules to pass through easily.
Certain health conditions and diseases, including inflammation and vitamin D deficiency, can damage peritubular capillaries. This damage can lead to capillary rarefaction, or a loss in density in the capillaries. Density is the amount of mass an object has compared to its volume. The loss in density affects how they work.
Damaged peritubular capillaries aren’t very good at repairing themselves. Because damaged capillaries can’t work like they should, peritubular capillary rarefaction is associated with kidney disease and hypertension (high blood pressure). These conditions are very common. Nearly half of all adults in the United States have hypertension, and around 15% of adults have some type of chronic kidney disease. Untreated, kidney disease can lead to kidney failure.
Kidney disease can result from or occur along with several conditions, including:
You may not always be able to prevent damage to your peritubular capillaries. But you can lower your risk of kidney problems and other health conditions by focusing on staying healthy overall. This includes:
Call your provider if you have signs of kidney disease, including:
A note from Cleveland Clinic
Peritubular capillaries play an essential role in helping your urinary system filter waste from your blood. They also reabsorb useful nutrients that keep you healthy. You have millions of peritubular capillaries in your kidneys. These tiny blood vessels are so small that you need a microscope to see them. To keep these and other capillaries working like they should, focus on your overall health. Drink plenty of water, make smart dietary choices, see your provider for regular checkups and maintain a healthy weight.
Last reviewed by a Cleveland Clinic medical professional on 09/30/2021.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy