Question

There is a pair of bean-shaped organs P in the human body towards the back, just above the waist. A waste product Q formed by the decomposition of unused proteins in the liver is brought into organ P through blood by an artery R. The numerous tiny filters S present in organ P clean the dirty blood by removing the waste product Q. The clean blood goes into circulation through a vein T. The waste substance Q, other waste salts, and excess water form a yellowish liquid U which goes from organ P into a bag-like structure V through two tubes W. This liquid is then thrown out of the body through a tube X.
(a) What is (i) organ P, and (ii) waste substance Q?
(b) Name (i) artery R, and (ii) vein T.
(c) What are tiny filters S known as?
(d) Name (i) liquid U (ii) structure V (iii) tubes W, and (iv) tube X.

Answer 1

(a)
(i)  Kidneys are bean shaped organs in the human body, towards the back of the body, just above the waist. Hence, organs P are kidneys.
(ii)  Urea is the waste product that is formed by the decomposition of unused proteins in the liver. Hence, the waste substance Q represents urea. 

(b)
(i) Urea (substance Q) is brought into kidney (organ P) through blood by an artery called renal artery. Hence, R represents renal artery.
(ii) The numerous tiny filters called nephrons (S) present in the kidneys (organ P), clean the dirty blood by removing the waste product Q (urea). The clean blood then goes into circulation through T, i.e. renal vein. Hence, vein T represents the renal vein.

(c) The tiny filters S are known as nephrons.

(d) The waste substance Q (urea), other waste salts and excess water form a yellowish liquid called urine (U). Urine goes from organ P (kidney) into a bag-like structure V, i.e. urinary bladder, through two tubes W, called ureters. This urine is then thrown out of the body     through tube X, called urethra.
Hence, (i) the liquid U is urine, (ii) structure V is urinary bladder, (iii) tubes W is ureters, and (iv) tube X is the urethra.