Since urea formation takes place in liver.

Complete reabsorption by active transport takes places for glucose in the proximal convoluted tubules.

Under fasting conditions and in uncontrolled diabetes,the liver produces large amount of ketone bodies like acetoacetate, dihydroxy butyrate. The presence of excess ketone bodies in blood or urine is termed ketonemic and ketonuria respectively.

(i)Glomerular capillary pressure (45 mm Hg) favours filteration.
(ii)The colloidal osmotic pressure (due to plasma proteins, particularly albumin) acts against filteration.Its value is ~20 mmHg.
(iii)The filterate pressure due to the glomerular filterate filled in the Bowman’s capsule also acts against filteration. Its value is ~10 mmHg.
Net filteration pressure
= 45 – (20 + 10) mm Hg
= 15 mm of Hg (10 – 20 mm of Hg)

Urea NH₂ – CO – NH₂ is formed from two molecules of ammonia and one molecule of carbon dioxide. Amolecule of ammonia combines with carbondioxide to form carbonyl phosphate. It reacts with ornithine to form citrulline. Citrulline accepts another molecule of NH₄⁺ giving rise to arginine. Arginine is hydrolysed into urea and ornithine with the help of enzyme arginase.

Some animals have dual behaviour of excretion eg.earthworm. It excretes ammonia (hence called ammonotelic) when enough water is available but excretes urea (ureotelic) in dry conditions.

Bowman’s glands are located in the olfactory epithelium of our nose.

Lysozyme is an antibacterial agent which is secreted by the major salivary glands.