Which renal structure filters the blood

Two ureters. These narrow tubes carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.

This triangle-shaped, hollow organ is located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to two cups of urine for two to five hours. Common Diseases and Disorders. When you select "Subscribe" you will start receiving our email newsletter.

Use the links at the bottom of any email to manage the type of emails you receive or to unsubscribe. See our privacy policy for additional details. Learn Site. The Kidneys Are Retroperitoneal Organs in the Abdomen The kidneys are located behind the peritoneum, and so are called retroperitoneal organs.

The Kidneys Are Composed of Three Main Sections Each kidney consists of an outer renal cortex, an inner renal medulla, and a renal pelvis. Get our awesome anatomy emails! About News Contact. All Rights Reserved. All these jobs make the kidneys essential to keeping the body working as it should. Blood travels to each kidney through the renal artery. The artery enters the kidney at the hilus pronounced: HY-luss , the indentation in middle of the kidney that gives it its bean shape.

The artery then branches so blood can get to the nephrons pronounced: NEH-fronz — 1 million tiny filtering units in each kidney that remove the harmful substances from the blood. Each of the nephrons contain a filter called the glomerulus pronounced: gluh-MER-yuh-lus. The fluid that is filtered out from the blood then travels down a tiny tube-like structure called a tubule pronounced: TOO-byool.

The tubule adjusts the level of salts, water, and wastes that will leave the body in the urine. Filtered blood leaves the kidney through the renal vein and flows back to the heart. Pee leaves the kidneys and travels through the ureters to the bladder. The bladder expands as it fills. When the bladder is full, nerve endings in its wall send messages to the brain. There are, on average, eight renal pyramids in each kidney. The renal pyramids along with the adjoining cortical region are called the lobes of the kidney.

The renal pelvis leads to the ureter on the outside of the kidney. On the inside of the kidney, the renal pelvis branches out into two or three extensions called the major calyces , which further branch into the minor calyces.

The ureters are urine-bearing tubes that exit the kidney and empty into the urinary bladder. Figure 2. The internal structure of the kidney is shown. Because the kidney filters blood, its network of blood vessels is an important component of its structure and function. The arteries, veins, and nerves that supply the kidney enter and exit at the renal hilum.

Renal blood supply starts with the branching of the aorta into the renal arteries which are each named based on the region of the kidney they pass through and ends with the exiting of the renal veins to join the inferior vena cava. The renal arteries split into several segmental arteries upon entering the kidneys. Each segmental artery splits further into several interlobar arteries and enters the renal columns, which supply the renal lobes.

The interlobar arteries split at the junction of the renal cortex and medulla to form the arcuate arteries. Cortical radiate arteries , as the name suggests, radiate out from the arcuate arteries. The cortical radiate arteries branch into numerous afferent arterioles, and then enter the capillaries supplying the nephrons.

Veins trace the path of the arteries and have similar names, except there are no segmental veins. As mentioned previously, the functional unit of the kidney is the nephron, illustrated in Figure 3. Each kidney is made up of over one million nephrons that dot the renal cortex, giving it a granular appearance when sectioned sagittally.