Question

When we say a nephrons is the structural and functional unit of the kidneys, we mean that
A. The kidney is made up of many nephrons.
B. The filtration of blood that occurs in the kidneys is because of what the nephrons do.
C. Urea formation occurs in the nephrons.
i) Only A and B
ii) Only A and B
iii) Only A and B
iv) A, B and C

Answer 1

Hint: Nephrons or uriniferous tubule is the structural and functional unit of the kidney. Each nephron consists of the glomerulus and the renal tubule. Nephrons are of two types: Cortical nephrons and juxta-medullary nephrons.

Complete answer:
The kidney is composed of many nephrons. The glomerulus and renal tubule are the part of nephrons. Glomerulus is a tuft of capillaries formed by the branching of afferent arterioles. Renal tubule begins with bowman’s capsule which encloses glomerulus. Bowman’s capsule is a blind double-walled cup shaped structure. Bowman’s capsule consists of an inner visceral and outer parietal membrane. Kidneys not only eliminate nitrogenous wastes but also help in the maintenance of ionic and acid-base balance of the body fluids.
The first step in the formation of urine is the filtration of blood. It is carried out by the glomerulus and it is known as glomerular filtration. The nephrons are responsible for the filtration of blood and formation of urine. For removing the waste product of the body, formation of urine takes place. The urine is formed in the kidney through filtration of blood.
The formation of urea takes place in the liver. The protein is digested and converted to ammonia which is further converted to the urea in the liver.

So the correct answer is option i) .

Note: 180 litres of glomerular filtrate is formed by the kidneys per day in a normal healthy individual. Uremia is the condition in which concentration of urea is increased in blood. Hematuria is the presence of blood in the urine.