Excretory System - Nephron Structure

The functions on what the parts inside the nephrons do in order to filter out wastes.

Nephron

basic filtering unit of the kidney. Each kidney has about a million of them, and they clean the blood by removing waste and balancing water, salt, and other substances.

Glomerulus

cluster of tiny blood vessels where blood pressure forces small particles out of the blood and into the Bowman's capsule. Big things like proteins and blood cells stay in the blood.

Loop of Henle

helps concentrate the urine. It reabsorbs water in the descending part and salts in the ascending part, saving water in the body.

Afferent arteriole

brings blood into the glomerulus. It's wider than the efferent arteriole, which helps create pressure so fluid and small particles get pushed out of the blood and into the nephron.

Efferent Arteriole

carries blood away from the glomerulus after filtration. It’s narrower, which keeps pressure high in the glomerulus and helps control how much gets filtered. It also leads to capillaries that help reabsorb useful stuff from the nephron.

Bowmans Capsule

Glomerulus Capsule

surrounds a tiny ball of capillaries called the glomerulus. It catches the fluid that leaks out of the blood, which includes water, salts, glucose, and waste, starting the process of making urine.

Renal Corpuscle

part of the nephron where blood is first filtered. It includes the glomerulus (a ball of capillaries) and the Bowman's capsule (which surrounds it). Together, they filter out water, salts, and small molecules from the blood to start forming urine.

Proximal Convoluted Tube

reabsorbs useful stuff from the fluid, like glucose, amino acids, and lots of water and salts, sending them back into the blood so they’re not lost in urine

Distal Convoluted Tubule

It responds to hormones and helps balance potassium, sodium, and acid levels before the fluid becomes urine.

Peritubular capillaries

tiny blood vessels that wrap around the nephron tubules. They come from the efferent arteriole and help reabsorb water, nutrients, and useful substances from the tubules back into the blood after filtration.

Collecting duct

carries urine from many nephrons to the bladder. It adjusts the final water level in urine depending on body needs, making it more or less concentrated.

Ascending Limb

goes back up and does the opposite—it pumps salts (like sodium and chloride) out into the kidney but doesn’t let water follow. This helps make the kidney salty, which helps concentrate urine later.

Descending Limb

goes down into the kidney and lets water leave the tube, but not salts. This makes the fluid inside more concentrated as water is reabsorbed into the blood.

ureter

tubes composed of smooth muscle that transport urine from the kidneys to the urinary bladder.