GENERAL HISTOLOGY

Detailed explanation-1: -Purines, creatinine and allantoin are nitrogenous wastes produced inside the body. Citrulline is not a nitrogenous waste.

Detailed explanation-2: -Nitrogenous waste products include urea, uric acid, and creatinine which are excreted as urine and sweat by the kidneys and the sweat glands respectively. Lungs and liver do not excrete nitrogenous wastes.

Detailed explanation-3: -Nitrogenous wastes which are removed by the kidneys are urea and ammonia. Urea is the main excretory product that is filtered and excreted out from the blood by the kidneys. Ammonia is mostly converted into urea in the liver and excreted out in the urine.

Detailed explanation-4: -Nitrogenous wastes tend to form toxic ammonia, which raises the pH of body fluids. The formation of ammonia itself requires energy in the form of ATP and large quantities of water to dilute it out of a biological system.