Given below is a highly simplified diagram of the human kidney cut open longitudinally. Answer the questions that follow.
(a) Define excretion.
(b) Name the functional units of the kidneys.
(c) Why does the cortex of the kidney show a dotted appearance?
(d) Mention two functions of the kidney.
(e) Write two differences in the composition of the blood flowing through the blood vessels, 'A' and 'B'.
(a) The process of removal of chemical wastes especially nitrogenous waste from the body is known as excretion.
(b) Nephrons
(c) As the cortex region contains numerous nephrons or kidney tubules, therefore, it shows a dotted appearance.
(d) Kidneys help in removing wastes or excretion and osmoregulation.
(e) The blood vessel ‘B’ is the renal artery and the blood vessel ‘A’ is the renal vein.
So the blood vessel ‘B’ contains oxygenated blood with a high concentration of urea and glucose whereas the blood vessel ‘A’ contains deoxygenated blood with a low concentration of urea and glucose as compared to the renal artery.