Ans.The functional unit of the kidneys is called nephron. There are over one million nephrons in each kidney.
Parts of Nephron
There are two parts of a nephron i.e. renal corpuscle and renal tubule.
1) The renal corpuscle is not tubular and has two parts i.e. glomerulus and Bowman's capsule.
i) Glomerulus is a network of capillaries.
ii)Bowman's capsule is a cup-shaped structure that encloses glomerulus.
2) The renal tubule is the part of nephron which starts after Bowman's capsule. We can divide it into three parts i.e
i)Its first portion is called the proximal convoluted tubule.
ii) Next portion is U-shaped and is called the Loop of Henle.
iii) The last portion of renal tubule is the distal convoluted tubule.
The distal convoluted tubules of many nephrons open in a single collecting duct. Many collecting ducts join together to form several hundred papillary ducts which drain Into renal pelvis.