Describe the role of liver,lungs,and skin in excretion.

(N/A) The liver,lungs,and skin play a significant role in the process of excretion.
Role of the liver:
The liver is the largest gland in vertebrates. It aids in the excretion of cholesterol,steroid hormones,vitamins,drugs,and other waste materials via bile. Urea is synthesized in the liver through the ornithine cycle. Ammonia,a toxic substance,is rapidly converted into urea in the liver and subsequently eliminated from the body. Additionally,the liver breaks down decomposed hemoglobin into bile pigments known as bilirubin and biliverdin.
Role of the lungs:
The lungs assist in removing gaseous waste materials,primarily carbon dioxide $(CO_2)$,from the body during respiration.
Role of the skin:
The skin contains various glands that facilitate the excretion of waste products through pores. It possesses two primary types of glands: sweat glands and sebaceous glands.
Sweat glands are highly vascular and tubular structures that filter waste products from the blood and excrete them as sweat. Sweat helps in the removal of excess salt $(NaCl)$,water,and small amounts of urea from the body.
Sebaceous glands are branched glands that secrete an oily substance known as sebum,which contains waxes,sterols,and fatty acids.