There are 3 different stages in urine formation that lead to the filtration of blood by the nephrons.
The following steps include –
Glomerular filtration – The first step begins when the blood is filtered by the glomerulus.
The afferent and efferent arterioles entering the glomerulus have a difference in their diameter which leads to an increase in blood pressure within the glomerulus.
This pressure leads to filtration.
The filtrate then enters the bowman’s capsule where it is named glomerular filtrate.
Tubular reabsorption – As the filtrate passes down to the proximal convoluted tubule, Henle’s loop, distal convoluted tubule the essential nutrients are reabsorbed.
The filtrate as it comes to the collecting duct, ADH acts on it which leads to the reabsorption of excess water thereby reducing the urine volume.
Tubular secretion – When the filtrate is in the proximal convoluted tubule, uric acid, and creatinine are secreted in it.
As the filtrate goes to the distal part, urea, potassium, and hydrogen ions are secreted in it.
Final Answer
Thus there are 3 main steps in urine formation – glomerular filtration, tubular reabsorption & secretion.