Which of the following statements is INCORRECT? I. Human kidneys can produce urine nearly six times more concentrated than the initial filtrate formed. II. An increase in body fluid volume can switch on the osmoreceptors and stimulate ADH. III. Substances like glucose, amino acids, N a+ , etc., in the filtrate, are reabsorbed actively by the renal tubule whereas the nitrogenous wastes are absorbed by passive transport IV. Each kidney has nearly one million complex tubular structures called nephrons which are the functional units.

Question

Which of the following statements is INCORRECT? I. Human kidneys can produce urine nearly six times more concentrated than the initial filtrate formed. II. An increase in body fluid volume can switch on the osmoreceptors and stimulate ADH. III. Substances like glucose, amino acids, N a+ , etc., in the filtrate, are reabsorbed actively by the renal tubule whereas the nitrogenous wastes are absorbed by passive transport IV. Each kidney has nearly one million complex tubular structures called nephrons which are the functional units. (A) I and II (B) III and IV (C) I, II and III (D) II, III and IV

Tardigrade Admin · Accepted Answer

Kidneys are the main organs of excretion. Each kidney contains around one million nephrons that take part in the formation of urine and thus these are regarded as functional units. Urine formation involves three steps: ultrafiltration, tubular reabsorption, and tubular secretion. Ultrafiltration produces around 180 liters of filtrate per day, but the urine produced is only 1.5 liters. This means that around 99% of filtrate is reabsorbed by the kidneys. Counter current mechanisms and hormones like ADH plays an important role in this process. ADH is an antidiuretic hormone that acts on DCT and bring about reabsorption of water and thus amount of water loss through urine is reduced.