Organs Involved in Excretion and the Formation of Urine

Organs Involved in Excretion

Excretion is the process by which the waste products from cell metabolism are eliminated from the blood.

Kidneys

Kidneys eliminate toxic substances resulting from cell metabolism through the urine.

Lungs

Lungs expel carbon dioxide from cellular respiration.

Liver

Liver produces a liquid called bile that helps to eliminate waste from digestion through feces.

Sweat Glands

Sweat glands, exocrine glands of the skin, are responsible for sweat excretion. Sweat is a liquid that is very similar to urine, but more diluted.

Nephrons and the Formation of Urine

Nephrons are the basic functional units of the kidneys. Each kidney has about one million. Urine is a liquid made of water, salts, and waste. This is done using filtration and reabsorption. About 1.5 liters of urine are produced every day.

Glomerulus

A mass of tiny capillaries through which blood and waste products pass.

Bowman's Capsule

A sac surrounding the glomerulus. Most small molecules like water and salts are filtered into Bowman's capsule from the capillaries.

Proximal Convulted Tubule (PCT)

Useful substances such as glucose, amino acids, ions, vitamins, and filtered water are reabsorbed here.

Collecting Duct

This duct collects urine and channels it into the renal pelvis. From there, urine is transported into the ureter.

Loop of Henle

It reabsorbs ions and some water.

Distal Convoluted Tubule (DCT)

Ions are reabsorbed there.