Question

Describe the mechanism of urine formation in human excretory system. Draw a labelled diagram to illustrate your answer.

Answer 1

Kidneys are the main excretory organs of the human body. There are about millions of nephron in each kidney. Each nephron contains a renal corpuscle and a renal tubule. The renal corpuscle consists of capillaries called the glomerulus, enclosed by a capsule called Bowman’s capsule. The blood containing wastes (like urea) enters the glomerulus. The glomerulus filters the blood. During filtration, the filtrate (containing substances such as glucose, amino acids, salts, water, and urea) present in the blood passes through the renal tubule, where substances needed by the body are reabsorbed, while wastes such as urea are collected and excreted in the urine. The nephron carries urine into the kidney’s collecting tubule, from which it is transported to the ureter. From the ureter, the urine passes into the urinary bladder. The urinary bladder stores urine until it is expelled from the body through an opening called the urethra.