Kidneys help to regulate the volume of fluid and various metabolites waste products in the body. Normally, kidney filter about 180 L of fluid daily but the volume actually excreted out is only a litre or two a day. Patients with kidney failures can be saved by dialysis and kidney transplant.

(a) Write the structure and function of Bowman's capsule.

(b) Although kidneys filter a large amount (about 180 L daily) of fluids, still the excretion from the body is only about a litre or two. Why?

(c) What is excretion? Why is it necessary for any living organism?

OR

(c) State two similarities between lungs and kidneys.

(a) Bowman's capsule is a double-walled cup-like structure. It is a part of nephron, the functional unit of kidney. The inner wall of the capsule is in close contact with a network of blood capillaries called glomerulus. The space between the inner and outer wall of the capsule is called Bowman's space. The structure helps in the filtration of blood. The waste products and excess fluids from the blood are filtered into the Bowman's space through the glomerulus.

(b) Although kidneys filter a large amount (about 180 L daily) of fluids, still the excretion from the body is only about a litre or two a day because most of the filtered fluid is reabsorbed back into the blood from the renal tubules.

(c) Excretion is the removal of waste products from the body. It is necessary for any living organism because the waste products are toxic in nature and can harm the body if they are not removed. The excretory system helps in the removal of these waste products from the body.