Describe the process of urine formation in kidneys.
The process of urine formation occurs in the nephrons. The process of urine formation occurs through the following steps:
a) Glomerular Filtration: It is the first step in urine formation and occurs when the blood enters the glomerulus. The capillaries of the glomerulus offer resistance to the flow of the blood and thus the blood pressure is set up. Due to this glomerular blood pressure, water and dissolved salts, glucose, drugs, urea and uric acid move from the glomerulus to the inside of the Bowman’s capsule. The process by which the fluid is separated from the blood in the glomerulus is called the glomerular filtration and the filtered substances are called glomerular filtrate. In the glomerular filtration process, large molecules, blood and platelets are unable to pass through the capillary walls.
b) Tubular Reabsorption: Reabsorption of water and nutrients such as glucose, amino acids, and some salts like NaCl which are useful to the body occurs from the proximal tubule into the blood, this is selective reabsorption because the excess of salts, urea and uric acid are not absorbed. Water is reabsorbed along the whole length of the nephron especially in the loop of Henle.
c) Tubular Secretion: The third process by which the kidneys clean blood (regulating its composition and volume) is called tubular secretion and it involves substances being added to the tubular fluid. This removes excessive quantities of certain dissolved substances from the body and also maintains the blood at a normal healthy pH (which is typically in the range pH 7.35 to pH 7.45).
The process of urine formation occurs in the nephrons. The process of urine formation occurs through the following steps:
a) Glomerular Filtration: It is the first step in urine formation and occurs when the blood enters the glomerulus. The capillaries of the glomerulus offer resistance to the flow of the blood and thus the blood pressure is set up. Due to this glomerular blood pressure, water and dissolved salts, glucose, drugs, urea and uric acid move from the glomerulus to the inside of the Bowman’s capsule. The process by which the fluid is separated from the blood in the glomerulus is called the glomerular filtration and the filtered substances are called glomerular filtrate. In the glomerular filtration process, large molecules, blood and platelets are unable to pass through the capillary walls.
b) Tubular Reabsorption: Reabsorption of water and nutrients such as glucose, amino acids, and some salts like NaCl which are useful to the body occurs from the proximal tubule into the blood, this is selective reabsorption because the excess of salts, urea and uric acid are not absorbed. Water is reabsorbed along the whole length of the nephron especially in the loop of Henle.
c) Tubular Secretion: The third process by which the kidneys clean blood (regulating its composition and volume) is called tubular secretion and it involves substances being added to the tubular fluid. This removes excessive quantities of certain dissolved substances from the body and also maintains the blood at a normal healthy pH (which is typically in the range pH 7.35 to pH 7.45).
