Question

Name the excretory unit of a kidney.

Answer 1

Hint: It is a thin walled, coiled duct lined by a single layer of epithelial cells and it starts with a cup -like structure called a bowman's capsule. It's a structural and functional unit of kidney. Main function is filtration of blood, reabsorption and secretion.

Complete answer:-
To answer this question you must know about the kidney and the parts it consists of.
The kidney is composed of the outer cortex and inner medulla, urine is collected into the renal pelvis and passed through the ureter. There are millions of microscopic tubes called uriniferous(renal) tubules of nephrons and it is the excretory unit of the kidney.
Nephron is thin walled coiled duct lined by the single layer of epithelial cells, it is the structural and functional unit of kidney, its proximal end has no opening whereas the distal end opens into a collecting tubule. All collecting tubules then open into the ureter. The main function of Nephron is to convert blood into urine by using 4 mechanisms: filtration, reabsorption, secretion and excretion.
Nephron consist malpighian body which maintain the blood circulation under high pressure and facilitate ultrafiltration during urine formation, it has a cup shaped structure called as bowman’s capsule and within the cup shaped structure of bowman’s capsule lies a network of capillaries called glomerulus which is formed by afferent arteriole and there is a another blood vessel efferent arteriole carries blood away from the glomerulus.

Note:-
Kidneys not only do excretion it also helps to adjust the potassium, sodium and chlorine ion concentration and regulation of acid base balance i.e pH of the body fluids. There are around 1,000,000 nephrons in every human kidney.